7天学习opengl入门

http://blog.csdn.net/slience_perseverance/article/details/8096233

10月13号下午3:00队长给我开了一个会，10.14号开始学习opengl

今天10月21号，期间，虽然有时候课程很满，但每天都至少写一个程序。

当然，这些只是我7天来业余时间的学习，我觉得这个网址不错，大家如果也想学习opengl，并且具有一定的C语言C++基础，入门课程推荐大家去学习这个网址http://www.cnblogs.com/crazyxiaom/articles/2073586.html

我的这些代码等都是从这个网址学习的，推荐你还是去这个网址学习，那更全更准确。

PS：“今天”（发表文章的今天）把我入门学习的资料送给一块儿学习的同学了，看着那厚厚的一叠折折状状的资料，我穿越了，我很清晰的看到了我接下来的学习生活--将会更加投入，将会有更厚更厚的资料进入我的大脑！

10.14

今天写了15个程序。这些是画二维图形的基础。

开始的时候犯了一个错误，以为坐标范围是像素点呢，后来才知道坐标范围是-1~1；（0,0）在中心。

第三个程序到第15个程序都是在练习glBegin（）的使用，最后可以画一个近似圆的多边形。

GL_POINTS，GL_LINES，GL_LINE_STRIP，GL_LINE_LOOP，GL_TRIANGLES，GL_TRIANGLE_STRIP，GL_TRIANGLE_FAN

GL_POLYGON

1.

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/GLUT.H>
2. void myDisplay(void){
3. glClear(GL_COLOR_BUFFER_BIT);
4. glRectf(-0.5f, -0.4f, 0.5f, 0.5f);
5. glFlush();
6. }
7. int main(int argc, char *argv[])
8. {
9. glutInit(&argc,argv);
10. glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);
11. glutInitWindowPosition(100, 100);
12. glutInitWindowSize(400, 400);
13. glutCreateWindow("opengl??1");
14. glutDisplayFunc(&myDisplay);
15. glutMainLoop();
16. return 0;
17. }
18. </strong></span>

2.

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay(){
3. glClearColor(1.0, 1.0, 1.0, 0.0);
4. glClear(GL_COLOR_BUFFER_BIT);
5. glColor3f(1.0, 0.0, 0.0);
6. glRectf(-0.5f,-0.5f,0.5f,0.5f);
7. glFlush();
8. }
9. int main(int argc, char* argv[]){
10. glutInit(&argc, argv);
11. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
12. glutInitWindowPosition(400, 400);
13. glutInitWindowSize(200, 200);
14. glutCreateWindow("独立");
15. glutDisplayFunc(myDisplay);
16. glutMainLoop();
17. return 0;
18. }</strong></span>

3.

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1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay(){
3. glClearColor(1.0,1.0,1.0,0.0);
4. glClear(GL_COLOR_BUFFER_BIT);
5. glBegin(GL_POINTS);
6. glVertex2i(100, 100);
7. glVertex2i(50, 50);
8. glVertex2i(70, 70);
9. glVertex2f(0.3f, 0.3f);
10. glVertex2f(-0.3f, -0.3f);
11. glVertex2f(0.5f, 0.5f);
12. glVertex2d(0.2,0.5);
13. glVertex2d(-0.4, -0.6);
14. glVertex2d(0.3,0.6);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("study02");
25. glutDisplayFunc(&myDisplay);
26. glutMainLoop();
27. return 0;
28. }
29. </strong></span>

4.

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1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay(){
3. glClearColor(1.0,1.0,1.0,0.0);
4. glClear(GL_COLOR_BUFFER_BIT);
5. glColor3f(1.0,0.0,0.0);
6. glBegin(GL_LINES);
7. //glVertex2i(100, 100);
8. //glVertex2i(50, 50);
9. //glVertex2i(70, 70);
10. glVertex2f(0.3f, 0.3f);
11. glVertex2f(-0.3f, -0.3f);
12. glVertex2f(0.5f, 0.5f);
13. glVertex2d(0.2,0.5);
14. glVertex2d(-0.4, -0.6);
15. glVertex2d(0.3,0.6);
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("study03");
26. glutDisplayFunc(&myDisplay);
27. glutMainLoop();
28. return 0;
29. }
30. </strong></span>

5.

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_LINE_STRIP);
8. glVertex2f(0.1f, 0.8f);
9. glVertex2f(-0.1f, -0.8f);
10. glVertex2f(0.1f, -0.8f);
11. glVertex2f(-0.1f, 0.8f);
12. glVertex2f(0.1f, 0.9f);
13. glVertex2f(0.4f, 0.8f);
14. glEnd();
15. glFlush();
16. }
17. int main(int argc, char* argv[])
18. {
19. glutInit(&argc, argv);
20. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
21. glutInitWindowPosition(400,400);
22. glutInitWindowSize(400,400);
23. glutCreateWindow("Study04");
24. glutDisplayFunc(myDisplay);
25. glutMainLoop();
26. return 0;
27. }</strong></span>

6.1

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_LINE_LOOP);
8. glVertex2f(0.2f, 0.2f);
9. glVertex2f(-0.2f, 0.2f);
10. glVertex2f(-0.2f, -0.2f);
11. glVertex2f(0.2f, -0.2f);
12. //glVertex2f(0.1f, 0.9f);
13. //glVertex2f(0.4f, 0.8f);
14. glEnd();
15. glFlush();
16. }
17. int main(int argc, char* argv[])
18. {
19. glutInit(&argc, argv);
20. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
21. glutInitWindowPosition(400,400);
22. glutInitWindowSize(400,400);
23. glutCreateWindow("Study04");
24. glutDisplayFunc(myDisplay);
25. glutMainLoop();
26. return 0;
27. }</strong></span>

7

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_TRIANGLES);
8. //glVertex2f(0.2f, 0.2f);
9. //glVertex2f(-0.2f, 0.2f);
10. //glVertex2f(-0.2f, -0.2f);
11. glVertex2f(0.8f, 0.4f);
12. glVertex2f(0.4f, 0.8f);
13. glVertex2f(0.0f, 0.0f);
14. //glVertex2f(0.1f, 0.9f);
15. //glVertex2f(0.4f, 0.8f);
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

7.1

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_TRIANGLES);
8. glVertex2f(0.2f, 0.2f);
9. glVertex2f(-0.2f, 0.2f);
10. glVertex2f(-0.2f, -0.2f);
11. glEnd();
12. glBegin(GL_TRIANGLES);
13. glVertex2f(0.8f, 0.4f);
14. glVertex2f(0.4f, 0.8f);
15. glVertex2f(0.0f, 0.0f);
16. //glVertex2f(0.1f, 0.9f);
17. //glVertex2f(0.4f, 0.8f);
18. glEnd();
19. glFlush();
20. }
21. int main(int argc, char* argv[])
22. {
23. glutInit(&argc, argv);
24. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
25. glutInitWindowPosition(400,400);
26. glutInitWindowSize(400,400);
27. glutCreateWindow("Study04");
28. glutDisplayFunc(myDisplay);
29. glutMainLoop();
30. return 0;
31. }</strong></span>

7.2

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_TRIANGLES);
8. glVertex2f(0.2f, 0.2f);
9. glVertex2f(-0.2f, 0.2f);
10. glVertex2f(-0.2f, -0.2f);
11. glVertex2f(0.8f, 0.4f);
12. glVertex2f(0.4f, 0.8f);
13. glVertex2f(0.0f, 0.0f);
14. //glVertex2f(0.1f, 0.9f);
15. //glVertex2f(0.4f, 0.8f);
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

7.3

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_TRIANGLES);
8. glVertex2f(0.2f, 0.2f);
9. glVertex2f(-0.2f, 0.2f);
10. glVertex2f(-0.2f, -0.2f);
11. glVertex2f(0.8f, 0.4f);
12. glVertex2f(0.4f, 0.8f);
13. glVertex2f(0.0f, 0.0f);
14. glVertex2f(0.1f, 0.9f);
15. glVertex2f(0.4f, 0.8f);
16. glVertex2f(0.9f,0.3f);
17. glEnd();
18. glFlush();
19. }
20. int main(int argc, char* argv[])
21. {
22. glutInit(&argc, argv);
23. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
24. glutInitWindowPosition(400,400);
25. glutInitWindowSize(400,400);
26. glutCreateWindow("Study04");
27. glutDisplayFunc(myDisplay);
28. glutMainLoop();
29. return 0;
30. }</strong></span>

8.

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_TRIANGLE_STRIP);
8. glVertex2f(0.0f,0.0f);
9. glVertex2f(0.4f,0.8f);
10. glVertex2f(0.8f,0.4f);
11. glVertex2f(0.8f,0.5f);
12. glVertex2f(-0.1f,0.9f);
13. glEnd();
14. glFlush();
15. }
16. int main(int argc, char* argv[])
17. {
18. glutInit(&argc, argv);
19. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
20. glutInitWindowPosition(400,400);
21. glutInitWindowSize(400,400);
22. glutCreateWindow("Study04");
23. glutDisplayFunc(myDisplay);
24. glutMainLoop();
25. return 0;
26. }</strong></span>

9.

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_TRIANGLE_FAN);
8. glVertex2f(0.0f,0.0f);
9. glVertex2f(0.4f,0.8f);
10. glVertex2f(0.8f,0.4f);
11. glVertex2f(0.8f,-0.5f);
12. glVertex2f(0.1f,-0.9f);
13. glEnd();
14. glFlush();
15. }
16. int main(int argc, char* argv[])
17. {
18. glutInit(&argc, argv);
19. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
20. glutInitWindowPosition(400,400);
21. glutInitWindowSize(400,400);
22. glutCreateWindow("Study04");
23. glutDisplayFunc(myDisplay);
24. glutMainLoop();
25. return 0;
26. }</strong></span>

10.

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_POLYGON);
8. glVertex2f(0.0f,0.0f);
9. glVertex2f(0.8f,0.4f);
10. glVertex2f(0.4f,0.8f);
11. glVertex2f(0.8f,-0.5f);
12. glVertex2f(0.1f,-0.9f);
13. glEnd();
14. glFlush();
15. }
16. int main(int argc, char* argv[])
17. {
18. glutInit(&argc, argv);
19. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
20. glutInitWindowPosition(400,400);
21. glutInitWindowSize(400,400);
22. glutCreateWindow("Study04");
23. glutDisplayFunc(myDisplay);
24. glutMainLoop();
25. return 0;
26. }</strong></span>

11.

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(1.0,0.0,0.0);
7. glBegin(GL_QUADS);
8. glVertex2f(0.2f, 0.2f);
9. glVertex2f(0.2f, -0.2f);
10. glVertex2f(-0.2f,-0.2f);
11. glVertex2f(-0.2f,0.2f);
12. glVertex2f(0.3f, 0.3f);
13. glVertex2f(0.3f, 0.7f);
14. glVertex2f(0.7f,1.0f);
15. glVertex2f(0.7f,0.3f);
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

12

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const int n = 20;
4. const GLfloat R = 0.5f;
5. const GLfloat Pi = 3.14159265358979f;
6. void myDisplay()
7. {
8. glClearColor(1.0,1.0,1.0,0.0);
9. glClear(GL_COLOR_BUFFER_BIT);
10. glColor3f(1.0,0.0,0.0);
11. glBegin(GL_POLYGON);
12. for(int i=0;i<n;++i)
13. {
14. glVertex2f(R*cos(2*Pi/n*i), R*sin(2*Pi/n*i));
15. }
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

12.1

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const int n = 30;
4. const GLfloat R = 0.5f;
5. const GLfloat Pi = 3.14159265358979f;
6. void myDisplay()
7. {
8. glClearColor(1.0,1.0,1.0,0.0);
9. glClear(GL_COLOR_BUFFER_BIT);
10. glColor3f(1.0,0.0,0.0);
11. glBegin(GL_POLYGON);
12. for(int i=0;i<n;++i)
13. {
14. glVertex2f(R*cos(2*Pi/n*i), R*sin(2*Pi/n*i));
15. }
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

12.2

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const int n = 50;
4. const GLfloat R = 0.5f;
5. const GLfloat Pi = 3.14159265358979f;
6. void myDisplay()
7. {
8. glClearColor(1.0,1.0,1.0,0.0);
9. glClear(GL_COLOR_BUFFER_BIT);
10. glColor3f(1.0,0.0,0.0);
11. glBegin(GL_POLYGON);
12. for(int i=0;i<n;++i)
13. {
14. glVertex2f(R*cos(2*Pi/n*i), R*sin(2*Pi/n*i));
15. }
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

13

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1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat R = 0.5f;
4. const GLfloat Pi = 3.14159265358979f;
5. void myDisplay()
6. {
7. GLfloat PointA[2] = {0,R};
8. GLfloat PointB[2] = {R*cos(162*Pi/180),R*sin(162*Pi/180)};
9. GLfloat PointC[2] = {R*cos(234*Pi/180),R*sin(234*Pi/180)};
10. GLfloat PointD[2] = {R*cos(306*Pi/180),R*sin(306*Pi/180)};
11. GLfloat PointE[2] = {R*cos(18*Pi/180),R*sin(18*Pi/180)};
12. glClearColor(1.0,1.0,1.0,0.0);
13. glClear(GL_COLOR_BUFFER_BIT);
14. glColor3f(1.0,0.0,0.0);
15. glBegin(GL_LINE_LOOP);
16. glVertex2fv(PointA);
17. glVertex2fv(PointC);
18. glVertex2fv(PointE);
19. glVertex2fv(PointB);
20. glVertex2fv(PointD);
21. glEnd();
22. glFlush();
23. }
24. int main(int argc, char* argv[])
25. {
26. glutInit(&argc, argv);
27. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
28. glutInitWindowPosition(400,400);
29. glutInitWindowSize(400,400);
30. glutCreateWindow("Study04");
31. glutDisplayFunc(myDisplay);
32. glutMainLoop();
33. return 0;
34. }</strong></span>

10.15

以下程序诸个描述

14.用很多线段的连线去模拟一个正玄函数线。用多条短的线段去模拟复杂的曲线或弧线似乎是一个很好的思维，在这思维下可以画出很多复杂的函数曲线

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. void myDisplay()
5. {
6. GLfloat x;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glColor3f(0.0,0.0,1.0);
10. glBegin(GL_LINES);
11. glVertex2f(-1.0f, 0.0f);
12. glVertex2f(1.0f, 0.0f);
13. glVertex2f(0.0f, -1.0f);
14. glVertex2f(0.0f, 1.0f);
15. glEnd();
16. glBegin(GL_LINE_STRIP);
17. for(x=-1.0f/factor;x<1.0f/factor;x+=0.01)
18. {
19. glVertex2f(x*factor, sin(x)*factor);
20. }
21. glEnd();
22. glFlush();
23. }
24. int main(int argc, char* argv[])
25. {
26. glutInit(&argc, argv);
27. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
28. glutInitWindowPosition(400,400);
29. glutInitWindowSize(400,400);
30. glutCreateWindow("Study04");
31. glutDisplayFunc(myDisplay);
32. glutMainLoop();
33. return 0;
34. }</strong></span>

15.上周上机实验时设置点的大小总是不通过，今天发现设置点的大小不是那么难。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. void myDisplay()
5. {
6. GLfloat x;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glColor3f(0.0,0.0,1.0);
10. glPointSize(5.0f);
11. glBegin(GL_POINTS);
12. glVertex2f(0.0f, 0.0f);
13. glVertex2f(0.4f, 0.4f);
14. glVertex2f(-0.2f,0.3f);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("Study04");
25. glutDisplayFunc(myDisplay);
26. glutMainLoop();
27. return 0;
28. }</strong></span>

15.1 这是一个点的大小设置的有点夸张的程序

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. void myDisplay()
5. {
6. GLfloat x;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glColor3f(0.0,0.0,1.0);
10. glPointSize(50.0f);
11. glBegin(GL_POINTS);
12. glVertex2f(0.0f, 0.0f);
13. glVertex2f(0.4f, 0.4f);
14. glVertex2f(-0.2f,0.3f);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("Study04");
25. glutDisplayFunc(myDisplay);
26. glutMainLoop();
27. return 0;
28. }</strong></span>

16.设置了线宽

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. void myDisplay()
5. {
6. GLfloat x;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glColor3f(0.0,0.0,1.0);
10. glLineWidth(5.0f);
11. glBegin(GL_LINE_STRIP);
12. glVertex2f(0.0f, 0.0f);
13. glVertex2f(0.4f, 0.4f);
14. glVertex2f(-0.2f,0.3f);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("Study04");
25. glutDisplayFunc(myDisplay);
26. glutMainLoop();
27. return 0;
28. }</strong></span>

16.1 设置了夸张的线宽

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. void myDisplay()
5. {
6. GLfloat x;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glColor3f(0.0,0.0,1.0);
10. glLineWidth(50.0f);
11. glBegin(GL_LINE_STRIP);
12. glVertex2f(0.0f, 0.0f);
13. glVertex2f(0.4f, 0.4f);
14. glVertex2f(-0.2f,0.3f);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("Study04");
25. glutDisplayFunc(myDisplay);
26. glutMainLoop();
27. return 0;
28. }</strong></span>

17. 画圆。圆心和周长上的点的连线，线加粗。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. class screenPt
5. {
6. private :
7. GLint x,y;
8. public:
9. screenPt()
10. {
11. x=y=0;
12. }
13. void setCoords(GLint xCoordValue,GLint yCoordValue)
14. {
15. x=xCoordValue;
16. y=yCoordValue;
17. }
18. GLint getx() const
19. {
20. return x;
21. }
22. GLint gety() const
23. {
24. return y;
25. }
26. void incrementx()
27. {
28. x++;
29. }
30. void decrementy()
31. {
32. y--;
33. }
34. };
35. void line(GLint x1, GLint y1, GLint x2, GLint y2){
36. glClearColor(1.0,1.0,1.0,0.0);
37. glClear(GL_COLOR_BUFFER_BIT);
38. glColor3f(1.0, 0.0, 0.0);
39. glLineWidth(5.0f);
40. glBegin(GL_LINES);
41. glVertex2f(x1/200.0f, y1/200.0f);
42. glVertex2f(x2/200.0f, y2/200.0f);
43. //glEnd();
44. glFlush();
45. }
46. void circleMidpoint(GLint xc,GLint yc,GLint radius)
47. {
48. screenPt circPt;
49. GLint p=1-radius;
50. circPt.setCoords(0,radius);
51. void circlePlotPoints (GLint,GLint,screenPt);
52. circlePlotPoints(xc, yc, circPt);
53. while(circPt.getx()<circPt.gety())
54. {
55. circPt.incrementx();
56. if(p<0)
57. p+=2*circPt.getx() +1;
58. else
59. {
60. circPt.decrementy();
61. p+=2*(circPt.getx()-circPt.gety())+1;
62. }
63. circlePlotPoints(xc,yc,circPt);
64. }
65. }
66. void circlePlotPoints(GLint xc,GLint yc,screenPt circPt)
67. {
68. line(xc, yc, xc+circPt.getx(),yc+circPt.gety());
69. line(xc, yc, xc-circPt.getx(),yc+circPt.gety());
70. line(xc, yc, xc+circPt.getx(),yc-circPt.gety());
71. line(xc, yc, xc-circPt.getx(),yc-circPt.gety());
72. line(xc, yc, xc+circPt.gety(),yc+circPt.getx());
73. line(xc, yc, xc-circPt.gety(),yc+circPt.getx());
74. line(xc, yc, xc+circPt.gety(),yc-circPt.getx());
75. line(xc, yc, xc-circPt.gety(),yc-circPt.getx());
76. }
77. void  Mycircle(void)
78. {
79. circleMidpoint(100,80,50);
80. glEnd();
81. glFlush();
82. }
83. int main(int argc, char* argv[])
84. {
85. glutInit(&argc, argv);
86. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
87. glutInitWindowPosition(400,400);
88. glutInitWindowSize(400,400);
89. glutCreateWindow("Study04");
90. glutDisplayFunc(&Mycircle);
91. glutMainLoop();
92. return 0;
93. }
94. </strong></span>

17.1 画圆。圆心和周长上的点的连线，线稍细。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. const GLfloat factor = 0.1f;
4. class screenPt
5. {
6. private :
7. GLint x,y;
8. public:
9. screenPt()
10. {
11. x=y=0;
12. }
13. void setCoords(GLint xCoordValue,GLint yCoordValue)
14. {
15. x=xCoordValue;
16. y=yCoordValue;
17. }
18. GLint getx() const
19. {
20. return x;
21. }
22. GLint gety() const
23. {
24. return y;
25. }
26. void incrementx()
27. {
28. x++;
29. }
30. void decrementy()
31. {
32. y--;
33. }
34. };
35. void line(GLint x1, GLint y1, GLint x2, GLint y2){
36. glClearColor(1.0,1.0,1.0,0.0);
37. glClear(GL_COLOR_BUFFER_BIT);
38. glColor3f(1.0, 0.0, 0.0);
39. glLineWidth(1.0f);
40. glBegin(GL_LINES);
41. glVertex2f(x1/200.0f, y1/200.0f);
42. glVertex2f(x2/200.0f, y2/200.0f);
43. //glEnd();
44. glFlush();
45. }
46. void circleMidpoint(GLint xc,GLint yc,GLint radius)
47. {
48. screenPt circPt;
49. GLint p=1-radius;
50. circPt.setCoords(0,radius);
51. void circlePlotPoints (GLint,GLint,screenPt);
52. circlePlotPoints(xc, yc, circPt);
53. while(circPt.getx()<circPt.gety())
54. {
55. circPt.incrementx();
56. if(p<0)
57. p+=2*circPt.getx() +1;
58. else
59. {
60. circPt.decrementy();
61. p+=2*(circPt.getx()-circPt.gety())+1;
62. }
63. circlePlotPoints(xc,yc,circPt);
64. }
65. }
66. void circlePlotPoints(GLint xc,GLint yc,screenPt circPt)
67. {
68. line(xc, yc, xc+circPt.getx(),yc+circPt.gety());
69. line(xc, yc, xc-circPt.getx(),yc+circPt.gety());
70. line(xc, yc, xc+circPt.getx(),yc-circPt.gety());
71. line(xc, yc, xc-circPt.getx(),yc-circPt.gety());
72. line(xc, yc, xc+circPt.gety(),yc+circPt.getx());
73. line(xc, yc, xc-circPt.gety(),yc+circPt.getx());
74. line(xc, yc, xc+circPt.gety(),yc-circPt.getx());
75. line(xc, yc, xc-circPt.gety(),yc-circPt.getx());
76. }
77. void  Mycircle(void)
78. {
79. circleMidpoint(100,80,50);
80. glEnd();
81. glFlush();
82. }
83. int main(int argc, char* argv[])
84. {
85. glutInit(&argc, argv);
86. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
87. glutInitWindowPosition(400,400);
88. glutInitWindowSize(400,400);
89. glutCreateWindow("Study04");
90. glutDisplayFunc(&Mycircle);
91. glutMainLoop();
92. return 0;
93. }
94. </strong></span>

18. 设置线的模式

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong><span style="white-space:pre">    </span>glEnable(GL_LINE_STIPPLE);//激活模式选择
2. glLineStipple(2,0x3333);//单位线，虚实匹配</strong></span>

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include <GL/glut.h>
2. #include<math.h>
3. void myDisplay()
4. {
5. glClearColor(1.0,1.0,1.0,0.0);
6. glClear(GL_COLOR_BUFFER_BIT);
7. glColor3f(0.0,0.0,1.0);
8. glEnable(GL_LINE_STIPPLE);
9. glLineStipple(2,0x3333);
10. glLineWidth(3.0f);
11. glBegin(GL_LINES);
12. glVertex2f(-1.0f, 0.0f);
13. glVertex2f(1.0f, 0.0f);
14. glVertex2f(0.0f, -1.0f);
15. glVertex2f(0.0f, 1.0f);
16. glEnd();
17. glFlush();
18. }
19. int main(int argc, char* argv[])
20. {
21. glutInit(&argc, argv);
22. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
23. glutInitWindowPosition(400,400);
24. glutInitWindowSize(400,400);
25. glutCreateWindow("Study04");
26. glutDisplayFunc(myDisplay);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

19.练习一下程序的基本流程。不能看书，自己敲完。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(0.0,0.0,1.0);
7. glLineWidth(5.0f);
8. glBegin(GL_LINES);
9. glVertex2f(0.0f, 0.0f);
10. glVertex2f(0.6f,0.8f);
11. glEnd();
12. glFlush();
13. }
14. int main(int argc, char* argv[])
15. {
16. glutInit(&argc, argv);
17. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
18. glutInitWindowPosition(400,400);
19. glutInitWindowSize(400,400);
20. glutCreateWindow("study");
21. glutDisplayFunc(myDisplay);
22. glutMainLoop();
23. return 0;
24. }</strong></span>

20.opengl中面是具有两面的，opengl画点的顺序不变，但从面的两个面来看这些点的相连顺序相反。设置不同的目标方向，出现的面就不同。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(0.0,0.0,1.0);
7. glPolygonMode(GL_FRONT,GL_FILL); //设置正面为填充模式
8. glPolygonMode(GL_BACK,GL_LINE);  //设置反面为线性模式
9. glFrontFace(GL_CCW);
10. glBegin(GL_POLYGON);
11. glVertex2f(-0.5f, -0.5f);
12. glVertex2f(0.0f,-0.5f);
13. glVertex2f(0.0f,0.0f);
14. glVertex2f(-0.5f,0.0f);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("study");
25. glutDisplayFunc(myDisplay);
26. glutMainLoop();
27. return 0;
28. }</strong></span>

20.

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>//glEnable(GL_CULL_FACE);
2. glCullFace(GL_FRONT);</strong></span>

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(0.0,0.0,1.0);
7. glPolygonMode(GL_FRONT,GL_FILL); //设置正面为填充模式
8. glPolygonMode(GL_BACK,GL_LINE);  //设置反面为线性模式
9. glFrontFace(GL_CW);
10. glBegin(GL_POLYGON);
11. glVertex2f(-0.5f, -0.5f);
12. glVertex2f(0.0f,-0.5f);
13. glVertex2f(0.0f,0.0f);
14. glVertex2f(-0.5f,0.0f);
15. glEnd();
16. glFlush();
17. }
18. int main(int argc, char* argv[])
19. {
20. glutInit(&argc, argv);
21. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
22. glutInitWindowPosition(400,400);
23. glutInitWindowSize(400,400);
24. glutCreateWindow("study");
25. glutDisplayFunc(myDisplay);
26. glutMainLoop();
27. return 0;
28. }</strong></span>

21 面具有两个面，可以剔除一个面，当面被挡着时可以剔除一个面。

glEnable(GL_CULL_FACE);//opengl是一个状态机，需要激活才能使用一些功能

glCullFace(GL_FRONT);//剔除正面

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>//glEnable(GL_CULL_FACE);
2. glCullFace(GL_FRONT);</strong></span>

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(0.0,0.0,1.0);
7. glPolygonMode(GL_FRONT,GL_FILL); //设置正面为填充模式
8. glPolygonMode(GL_BACK,GL_LINE);  //设置反面为线性模式
9. glFrontFace(GL_CCW);
10. glBegin(GL_POLYGON);
11. glVertex2f(-0.5f, -0.5f);
12. glVertex2f(0.0f,-0.5f);
13. glVertex2f(0.0f,0.0f);
14. glVertex2f(-0.5f,0.0f);
15. glEnd();
16. glColor3f(1.0,0.0,0.0);
17. //glEnable(GL_CULL_FACE);
18. glCullFace(GL_FRONT);
19. glBegin(GL_POLYGON);
20. glVertex2f(-0.5f, -0.5f);
21. glVertex2f(0.0f,-0.5f);
22. glVertex2f(0.0f,0.0f);
23. glVertex2f(-0.5f,0.0f);
24. glEnd();
25. glDisable(GL_CULL_FACE);
26. glFlush();
27. }
28. int main(int argc, char* argv[])
29. {
30. glutInit(&argc, argv);
31. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
32. glutInitWindowPosition(400,400);
33. glutInitWindowSize(400,400);
34. glutCreateWindow("study");
35. glutDisplayFunc(myDisplay);
36. glutMainLoop();
37. return 0;
38. }</strong></span>

21.1剔除了一个面后，被挡的面出现

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClearColor(1.0,1.0,1.0,0.0);
5. glClear(GL_COLOR_BUFFER_BIT);
6. glColor3f(0.0,0.0,1.0);
7. glPolygonMode(GL_FRONT,GL_FILL); //设置正面为填充模式
8. glPolygonMode(GL_BACK,GL_LINE);  //设置反面为线性模式
9. glFrontFace(GL_CCW);
10. glBegin(GL_POLYGON);
11. glVertex2f(-0.5f, -0.5f);
12. glVertex2f(0.0f,-0.5f);
13. glVertex2f(0.0f,0.0f);
14. glVertex2f(-0.5f,0.0f);
15. glEnd();
16. glColor3f(1.0,0.0,0.0);
17. glEnable(GL_CULL_FACE);
18. glCullFace(GL_FRONT);
19. glBegin(GL_POLYGON);
20. glVertex2f(-0.5f, -0.5f);
21. glVertex2f(0.0f,-0.5f);
22. glVertex2f(0.0f,0.0f);
23. glVertex2f(-0.5f,0.0f);
24. glEnd();
25. glDisable(GL_CULL_FACE);
26. glFlush();
27. }
28. int main(int argc, char* argv[])
29. {
30. glutInit(&argc, argv);
31. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
32. glutInitWindowPosition(400,400);
33. glutInitWindowSize(400,400);
34. glutCreateWindow("study");
35. glutDisplayFunc(myDisplay);
36. glutMainLoop();
37. return 0;
38. }</strong></span>

22 画板，镂空的实现

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong><span style="white-space:pre">    </span>glEnable(GL_POLYGON_STIPPLE);激活多面体镂空模式
2. glPolygonStipple(Mask); 镂空数组</strong></span>

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #include<stdio.h>
3. #include<STDLIB.H>
4. void myDisplay()
5. {
6. static GLubyte Mask[128];
7. FILE *fp;
8. fp = fopen("mmmm.bmp", "rb");
9. if(!fp)
10. exit(0);
11. if(fseek(fp, -(int)sizeof(Mask),SEEK_END))
12. exit(0);
13. if(!fread(Mask,sizeof(Mask),1,fp))
14. exit(0);
15. fclose(fp);
16. glClearColor(1.0,1.0,1.0,0.0);
17. glClear(GL_COLOR_BUFFER_BIT);
18. glColor3f(0.0,0.0,1.0);
19. glEnable(GL_POLYGON_STIPPLE);
20. glPolygonStipple(Mask);
21. glRectf(-0.5f,-0.5f,0.0f,0.0f);
22. glDisable(GL_POLYGON_STIPPLE);
23. glRectf(0.0f,0.0f,0.5f,0.5f);
24. glFlush();
25. }
26. int main(int argc, char* argv[])
27. {
28. glutInit(&argc, argv);
29. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
30. glutInitWindowPosition(400,400);
31. glutInitWindowSize(400,400);
32. glutCreateWindow("study");
33. glutDisplayFunc(myDisplay);
34. glutMainLoop();
35. return 0;
36. }</strong></span>

23 默认光滑模式

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #include<math.h>
3. const GLdouble Pi = 3.1415926536;
4. void myDisplay()
5. {
6. int i;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glBegin(GL_TRIANGLE_FAN);
10. glColor3f(0.0,0.0,1.0);
11. glVertex2f(0.0f,0.0f);
12. for(i=0;i<=8;++i)
13. {
14. glColor3f(i&0x04, i&0x02, i&0x01);
15. glVertex2f((float)cos(i*Pi/4), (float)sin(i*Pi/4));
16. }
17. glEnd();
18. glFlush();
19. }
20. int main(int argv, char* argc[])
21. {
22. glutInit(&argv, argc);
23. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
24. glutInitWindowPosition(400,400);
25. glutInitWindowSize(400,400);
26. glutCreateWindow("study");
27. glutDisplayFunc(myDisplay);
28. //Sleep(10*1000);
29. glutMainLoop();
30. return 0;
31. }</strong></span>

23.1 设置了清除色

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #include<math.h>
3. const GLdouble Pi = 3.1415926536;
4. void myDisplay()
5. {
6. int i;
7. glClearColor(1.0,1.0,1.0,0.0);
8. glClear(GL_COLOR_BUFFER_BIT);
9. glBegin(GL_TRIANGLE_FAN);
10. //glColor3f(0.0,0.0,1.0);
11. glVertex2f(0.0f,0.0f);
12. for(i=0;i<=8;++i)
13. {
14. glColor3f(i&0x04, i&0x02, i&0x01);
15. glVertex2f((float)cos(i*Pi/4), (float)sin(i*Pi/4));
16. }
17. glEnd();
18. glFlush();
19. }
20. int main(int argv, char* argc[])
21. {
22. glutInit(&argv, argc);
23. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
24. glutInitWindowPosition(400,400);
25. glutInitWindowSize(400,400);
26. glutCreateWindow("study");
27. glutDisplayFunc(myDisplay);
28. //Sleep(10*1000);
29. glutMainLoop();
30. return 0;
31. }</strong></span>

23.2 

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>glShadeModel(GL_FLAT);采用平板展现模式---其对应光滑渐变模式</strong></span>

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #include<math.h>
3. const GLdouble Pi = 3.1415926536;
4. void myDisplay()
5. {
6. int i;
7. glShadeModel(GL_FLAT);
8. glClearColor(1.0,1.0,1.0,0.0);
9. glClear(GL_COLOR_BUFFER_BIT);
10. glBegin(GL_TRIANGLE_FAN);
11. //glColor3f(0.0,0.0,1.0);
12. glVertex2f(0.0f,0.0f);
13. for(i=0;i<=8;++i)
14. {
15. glColor3f(i&0x04, i&0x02, i&0x01);
16. glVertex2f((float)cos(i*Pi/4), (float)sin(i*Pi/4));
17. }
18. glEnd();
19. glFlush();
20. }
21. int main(int argv, char* argc[])
22. {
23. glutInit(&argv, argc);
24. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
25. glutInitWindowPosition(400,400);
26. glutInitWindowSize(400,400);
27. glutCreateWindow("study");
28. glutDisplayFunc(myDisplay);
29. //Sleep(10*1000);
30. glutMainLoop();
31. return 0;
32. }</strong></span>

24 今天是周一，明天周二，计算机图形学上机实验，不能太给老是丢人，就勉强自己写了个三维的，借用隔壁同学的方法使它旋转起来了，发现这方法竟然是下一天的课程，呵呵

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #include<windows.h>
3. #include<math.h>
4. static int day = 200;
5. void myDisplay()
6. {
7. glEnable(GL_DEPTH_TEST); //启动深度测试
8. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //清空深度缓冲和颜色缓冲
9. glMatrixMode(GL_PROJECTION); //操作投影矩阵
10. glLoadIdentity(); //进行变换前通常把当前矩阵设置为单位矩阵
11. gluPerspective(75,1,1,400000000); //设置可视空间，得到透视效果（可视角，高宽比，最近可视距离，最远可视距离）
12. glMatrixMode(GL_MODELVIEW); //设置当前操作的矩阵为“模型视图矩阵”
13. glLoadIdentity(); //把当前矩阵设置为单位矩阵
14. gluLookAt(0,-200000000,200000000,0,0,0,0,0,1); //设定观察点位置（观察点位置，目标位置，观察者上方向）
15. glColor3f(1.0f,0.0f,0.0f);
16. //glRotatef(day/360.0*360.0, 0.0f,0.0f,-1.0f);
17. glutSolidSphere(69600000,50,50);
18. glColor3f(0.0f,0.0f,1.0f);
19. glRotatef(day, 0.0f,0.0f,-1.0f);
20. glTranslatef(150000000,0.0f,0.0f);
21. glutSolidSphere(15945000,50,50);
22. glColor3f(1.0f,1.0f,0.0f);
23. glRotatef(day/30.0*360.0-day,0.0f,0.0f,-1.0f);
24. glTranslatef(38000000,0.0f,0.0f);
25. glutSolidSphere(4345000,50,50);
26. glutSwapBuffers();
27. }
28. void play()
29. {
30. day++;
31. if(day >= 360)
32. day = 0;
33. myDisplay();
34. Sleep(100);
35. glutPostRedisplay();
36. }
37. int main(int argv, char* argc[])
38. {
39. glutInit(&argv, argc);
40. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
41. glutInitWindowPosition(400,400);
42. glutInitWindowSize(400,400);
43. glutCreateWindow("study");
44. glutDisplayFunc(play);
45. glutMainLoop();
46. return 0;
47. }</strong></span>

10.16

今天只有晚上有时间了，白天都满课

25 光照，材质等，不是很懂，光照必须要会用！

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #define WIDTH 400
3. #define HEIGHT 400
4. static GLfloat angle = 0.0f;
5. void myDisplay()
6. {
7. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
8. //创建透视效果视图
9. glMatrixMode(GL_PROJECTION); //操作投影矩阵
10. glLoadIdentity();  //当前矩阵设置为单位矩阵
11. gluPerspective(90.0f, 1.0f,1.0f,20.0f);  //得到透视效果
12. glMatrixMode(GL_MODELVIEW); //操作“模型视图”矩阵
13. glLoadIdentity();
14. gluLookAt(0.0,0.0,-10.0,0.0,0.0,0.0,0.0,1.0,0.0);
15. //定义太阳光源，它是一种白色光源
16. {
17. GLfloat sun_light_position[] = {0.0f,0.0f,0.0f,1.0f};
18. GLfloat sun_light_ambient[] = {0.0f,0.0f,0.0f,1.0f};
19. GLfloat sun_light_diffuse[] = {1.0f,1.0f,1.0f,1.0f};
20. GLfloat sun_light_specular[] = {1.0f,1.0f,1.0f,1.0f};
21. glLightfv(GL_LIGHT0, GL_POSITION, sun_light_position);
22. glLightfv(GL_LIGHT0, GL_AMBIENT, sun_light_ambient);
23. glLightfv(GL_LIGHT0, GL_DIFFUSE, sun_light_diffuse);
24. glLightfv(GL_LIGHT0, GL_SPECULAR, sun_light_specular);
25. glEnable(GL_LIGHT0);
26. glEnable(GL_LIGHTING);
27. glEnable(GL_DEPTH_TEST);
28. }
29. //定义太阳的材质并绘制太阳
30. {
31. GLfloat sun_mat_ambient[] = {0.0f,0.0f,0.0f,1.0f};
32. GLfloat sun_mat_diffuse[] = {0.0f,0.0f,0.0f,1.0f};
33. GLfloat sun_mat_specular[] = {0.0f,0.0f,0.0f,1.0f};
34. GLfloat sun_mat_emission[] = {0.5f,0.0f,0.0f,1.0f};
35. GLfloat sun_mat_shininess = 0.0f;
36. glMaterialfv(GL_FRONT, GL_AMBIENT, sun_mat_ambient); //环境变量
37. glMaterialfv(GL_FRONT, GL_DIFFUSE, sun_mat_diffuse); //散射模式
38. glMaterialfv(GL_FRONT, GL_SPECULAR, sun_mat_specular); //镜面反射
39. glMaterialfv(GL_FRONT, GL_EMISSION, sun_mat_emission); //发射，散发喷射
40. glMaterialf(GL_FRONT, GL_SHININESS, sun_mat_shininess);
41. glutSolidSphere(2.0,40,32);
42. }
43. //定义地球材质并绘制地球
44. {
45. GLfloat earth_mat_ambient[] = {0.0f,0.0f,0.5f,1.0f};
46. GLfloat earth_mat_diffuse[] = {0.0f,0.0f,0.5f,1.0f};
47. GLfloat earth_mat_specular[] = {0.0f,0.0f,1.0f,1.0f};
48. GLfloat earth_mat_emission[] = {0.0f,0.0f,0.0f,1.0f};
49. GLfloat earth_mat_shininess = 30.0f;
50. glMaterialfv(GL_FRONT, GL_AMBIENT, earth_mat_ambient); //环境变量
51. glMaterialfv(GL_FRONT, GL_DIFFUSE, earth_mat_diffuse); //散射模式
52. glMaterialfv(GL_FRONT, GL_SPECULAR, earth_mat_specular); //镜面反射
53. glMaterialfv(GL_FRONT, GL_EMISSION, earth_mat_emission); //发射，散发喷射
54. glMaterialf(GL_FRONT, GL_SHININESS, earth_mat_shininess);
55. glRotatef(angle,0.0f,-1.0f,0.0f);
56. glTranslatef(5.0f,0.0f,0.0f);
57. glutSolidSphere(1.5,40,32);
58. }
59. glutSwapBuffers();
60. }
61. void myIdle()
62. {
63. angle += 1.0f;
64. if(angle >= 360.0f)
65. angle = 0.0f;
66. myDisplay();
67. }
68. int main(int argc, char* argv[])
69. {
70. glutInit(&argc, argv);
71. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
72. glutInitWindowPosition(200,200);
73. glutInitWindowSize(WIDTH, HEIGHT);
74. glutCreateWindow("opengl光照演示");
75. glutDisplayFunc(&myDisplay);
76. glutIdleFunc(&myIdle); //回调
77. glutMainLoop();
78. return 0;
79. }</strong></span>

10.17

今天周三，满课，且晚上还有数据库上机实验，自己电脑不能用，中午看过这课后借同学的手机敲了代码练习

26 列表的使用（一次编译，多次使用，节省效率）、glutIdleFunc(&myIdle)调用cpu空闲资源且控制旋转角度，注意矩阵的push和pop

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. #include<math.h>
3. #include<windows.h>
4. #define WIDTH 400
5. #define HEIGHT 400
6. #define ColoredVertex(c,v) do{glColor3fv(c);glVertex3fv(v);}while(0)
7. GLfloat angle=0.0f;
8. void myDisplay()
9. {
10. static int list = 0;
11. if(list == 0)
12. {
13. GLfloat
14. PointA[] = {0.5f,-sqrt(6.0f)/12,-sqrt(3.0f)/6},
15. PointB[] = {-0.5f,-sqrt(6.0f)/12,-sqrt(3.0f)/6},
16. PointC[] = {0.0f,-sqrt(6.0f)/12,sqrt(3.0f)/3},
17. PointD[] = {0.0f,sqrt(6.0f)/4,0};
18. GLfloat
19. ColorR[] = {1,0,0},
20. ColorG[] = {0,1,0},
21. ColorB[] = {0,0,1},
22. ColorY[] = {1,1,0};
23. list = glGenLists(1);
24. glNewList(list,GL_COMPILE);
25. glBegin(GL_TRIANGLES);
26. ColoredVertex(ColorR,PointA);
27. ColoredVertex(ColorG,PointB);
28. ColoredVertex(ColorB,PointC);
29. ColoredVertex(ColorR,PointA);
30. ColoredVertex(ColorB,PointC);
31. ColoredVertex(ColorY,PointD);
32. ColoredVertex(ColorB,PointC);
33. ColoredVertex(ColorG,PointB);
34. ColoredVertex(ColorY,PointD);
35. ColoredVertex(ColorG,PointB);
36. ColoredVertex(ColorR,PointA);
37. ColoredVertex(ColorY,PointD);
38. glEnd();
39. glEndList();
40. glEnable(GL_DEPTH_TEST);
41. }
42. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
43. glPushMatrix();
44. glRotatef(angle,1,0.5,0);
45. glCallList(list);
46. glPopMatrix();
47. glutSwapBuffers();
48. }
49. void myIdle()
50. {
51. ++angle;
52. if(angle >= 360.0f)
53. angle = 0.0f;
54. Sleep(1000/10);
55. myDisplay();
56. }
57. int main(int argc, char* argv[])
58. {
59. glutInit(&argc,argv);
60. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
61. glutInitWindowPosition(200,200);
62. glutInitWindowSize(400,400);
63. glutCreateWindow("study");
64. glutDisplayFunc(&myDisplay);
65. glutIdleFunc(&myIdle);
66. glutMainLoop();
67. return 0;
68. }</strong></span>

10.18

今天学颜色的混合，会有半透明的效果

27. glBlendFunc(GL_ONE,GL_ZERO);完全使用源色

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClear(GL_COLOR_BUFFER_BIT);
5. glEnable(GL_BLEND);
6. glBlendFunc(GL_ONE,GL_ZERO);
7. glColor4f(1,0,0,0.5);
8. glRectf(-1,-1,0.5,0.5);
9. glColor4f(0,1,0,0.5);
10. glRectf(-0.5,-0.5,1,1);
11. glutSwapBuffers();
12. }
13. void myIdle()
14. {
15. myDisplay();
16. }
17. int main(int argc, char* argv[])
18. {
19. glutInit(&argc,argv);
20. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
21. glutInitWindowPosition(200,200);
22. glutInitWindowSize(400,400);
23. glutCreateWindow("study");
24. myDisplay();
25. glutDisplayFunc(&myDisplay);
26. glutIdleFunc(&myIdle);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

27.1两种颜色混合

glBlendFunc(GL_ONE, GL_ONE);，则表示完全使用源颜色和目标颜色，最终的颜色实际上就是两种颜色的简单相加。例如红色(1, 0, 0)和绿色(0, 1, 0)相加得到(1, 1, 0)，结果为黄色

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClear(GL_COLOR_BUFFER_BIT);
5. glEnable(GL_BLEND);
6. glBlendFunc(GL_ONE,GL_ONE);  //改动
7. glColor4f(1,0,0,0.5);
8. glRectf(-1,-1,0.5,0.5);
9. glColor4f(0,1,0,0.5);
10. glRectf(-0.5,-0.5,1,1);
11. glutSwapBuffers();
12. }
13. void myIdle()
14. {
15. myDisplay();
16. }
17. int main(int argc, char* argv[])
18. {
19. glutInit(&argc,argv);
20. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
21. glutInitWindowPosition(200,200);
22. glutInitWindowSize(400,400);
23. glutCreateWindow("study");
24. myDisplay();
25. glutDisplayFunc(&myDisplay);
26. glutIdleFunc(&myIdle);
27. glutMainLoop();
28. return 0;
29. }</strong></span>

27.2

GL_ONE_MINUS_SRC_ALPHA：表示用1.0减去源颜色的alpha值来作为因子。
GL_ONE_MINUS_DST_ALPHA：表示用1.0减去目标颜色的alpha值来作为因子。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. void myDisplay()
3. {
4. glClear(GL_COLOR_BUFFER_BIT);
5. glEnable(GL_BLEND);
6. glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);  //改动
7. glColor4f(1,0,0,0.5);
8. glRectf(-1,-1,0.5,0.5);
9. glColor4f(0,1,0,0.5);
10. glRectf(-0.5,-0.5,1,1);
11. glutSwapBuffers();
12. }
13. void myIdle()
14. {
15. myDisplay();
16. }
17. int main(int argc, char* argv[])
18. {
19. glutInit(&argc,argv);
20. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
21. glutInitWindowPosition(200,200);
22. glutInitWindowSize(400,400);
23. glutCreateWindow("study");
24. myDisplay();
25. glutDisplayFunc(&myDisplay);
26. glutIdleFunc(&myIdle);
27. glutMainLoop();
28. return 0;
29. }
30. </strong></span>

28 光源，绘制半透明物体，注意深度测试的控制

在进行三维混合时，不仅要考虑源因子和目标因子，还应该考虑深度缓冲区。必须先绘制所有不透明的物体，再绘制半透明的物体。在绘制半透明物体时前，还需要将深度缓冲区设置为只读形式，否则可能出现画面错误。

[cpp] view plaincopy

1. <span style="font-size:18px;"><strong>#include<GL/glut.h>
2. //在1,1,-1处设置白色的光源
3. void setLight()
4. {
5. static const GLfloat light_position[] = {1.0f,1.0f,-1.0f,1.0f};
6. static const GLfloat light_ambient[] = {0.2f,0.2f,0.2f,1.0f};
7. static const GLfloat light_diffuse[] = {1.0f,1.0f,1.0f,1.0f};
8. static const GLfloat light_specular[] = {1.0f,1.0f,1.0f,1.0f};
9. glLightfv(GL_LIGHT0,GL_POSITION, light_position);
10. glLightfv(GL_LIGHT0,GL_AMBIENT, light_ambient);
11. glLightfv(GL_LIGHT0,GL_DIFFUSE, light_diffuse);
12. glLightfv(GL_LIGHT0,GL_SPECULAR, light_specular);
13. glEnable(GL_LIGHT0);
14. glEnable(GL_LIGHTING);
15. glEnable(GL_DEPTH_TEST);
16. }
17. //设置材质
18. void setMatirial(const GLfloat mat_diffuse[4], GLfloat mat_shininess)
19. {
20. static const GLfloat mat_specular[] = {0.0f,0.0f,0.0f,1.0f};
21. static const GLfloat mat_emission[] = {0.0f,0.0f,0.0f,1.0f};
22. glMaterialfv(GL_FRONT,GL_AMBIENT_AND_DIFFUSE,mat_diffuse);
23. glMaterialfv(GL_FRONT,GL_SPECULAR,mat_specular);
24. glMaterialfv(GL_FRONT,GL_EMISSION,mat_emission);
25. glMaterialf(GL_FRONT,GL_SHININESS,mat_shininess);
26. }
27. void myDisplay()
28. {
29. //定义一些材质颜色
30. const static GLfloat red_color[] = {1.0f,0.0f,0.0f,1.0f};
31. const static GLfloat green_color[] = {0.0f,1.0f,0.0f,0.3333f};
32. const static GLfloat blue_color[] = {0.0f,0.0f,1.0f,0.5f};
33. //清除屏幕
34. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
35. //设置光源
36. setLight();
37. //启动混合并设置混合因子
38. glEnable(GL_BLEND);
39. glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
40. //以(0,0,0.5)为中心，绘制一个半径为0.3的不透明红色球体（离观察者最远）
41. setMatirial(red_color, 30.0);
42. glPushMatrix();
43. glTranslatef(0.0f,0.0f,0.5f);
44. glutSolidSphere(0.3,30,30);
45. glPopMatrix();
46. //绘制半透明物体
47. glDepthMask(GL_FALSE);
48. //以(0.2,0,-0.5)为中心，绘制一个半径为0.2的半透明蓝色球体（离观察者最近）
49. setMatirial(blue_color, 30.0);
50. glPushMatrix();
51. glTranslatef(0.2f,0.0f,-0.5f);
52. glutSolidSphere(0.2,30,30);
53. glPopMatrix();
54. //以(0.1,0,0)为中心，绘制一个半径为0.15的半透明绿色球体（在两球体之间）
55. setMatirial(green_color, 30.0);
56. glPushMatrix();
57. glTranslatef(0.1,0,0);
58. glutSolidSphere(0.15,30,30);
59. glPopMatrix();
60. //深度缓冲区恢复为可读可写模式
61. glDepthMask(GL_TRUE);
62. glutSwapBuffers();
63. }
64. void myIdle()
65. {
66. myDisplay();
67. }
68. int main(int argc, char* argv[])
69. {
70. glutInit(&argc,argv);
71. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
72. glutInitWindowPosition(200,200);
73. glutInitWindowSize(400,400);
74. glutCreateWindow("study");
75. myDisplay();
76. glutDisplayFunc(&myDisplay);
77. //glutIdleFunc(&myIdle);
78. glutMainLoop();
79. return 0;
80. }</strong></span>

10.19

29 读取bmp图片的宽度和高度值，代码跟下一个程序开头类似

主代码：

[cpp] view plaincopy

1. <pre name="code" class="cpp"><span style="font-size:18px;"><strong>static GLint ImageWidth;
2. static GLint ImageHeight;</strong></span></pre>
3. <pre></pre>
4. <p></p>
5. <pre></pre>
6. <pre name="code" class="cpp"><span style="font-size:18px;"><strong>//打开文件
7. FILE* pFile = fopen("1234.bmp", "rb");
8. if(pFile == 0)
9. exit(0);
10. //读取图象的大小信息
11. fseek(pFile, 0x0012, SEEK_SET);
12. fread(&ImageWidth,sizeof(ImageWidth),1,pFile);
13. fread(&ImageHeight,sizeof(ImageHeight),1,pFile);</strong></span></pre><br>
14. <p></p>
15. <p><span style="font-size:18px"><strong><img src="http://img.my.csdn.net/uploads/201210/27/1351343996_9120.png" alt=""><br>
16. </strong></span></p>
17. <p><span style="font-size:18px"><strong><br>
18. </strong></span></p>
19. <p><span style="font-size:18px"><strong>30 读取bmp图片文件--存像素数值，画出来</strong></span></p>
20. <p><span style="font-size:18px"><strong></strong></span></p>
21. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#include<GL/glut.h>
22. #include<stdio.h>
23. #include<stdlib.h>
24. #define FileName "1234.bmp"
25. static GLint ImageWidth;
26. static GLint ImageHeight;
27. static GLint PixelLength;
28. static GLubyte* PixelData;
29. void display()
30. {
31. /*清除屏幕并不必要
32. * 每次绘制时，画面都覆盖整个屏幕
33. * 因此无论是否清除屏幕，结果都一样
34. */
35. //glClear(GL_COLOR_BUFFER_BIT);
36. //绘制像素
37. glDrawPixels(ImageWidth,ImageHeight,
38. GL_BGR_EXT,GL_UNSIGNED_BYTE,PixelData);
39. //完成绘制
40. glutSwapBuffers();
41. }
42. int main(int argc, char* argv[])
43. {
44. //打开文件
45. FILE* pFile = fopen("1234.bmp", "rb");
46. if(pFile == 0)
47. exit(0);
48. //读取图象的大小信息
49. fseek(pFile, 0x0012, SEEK_SET);
50. fread(&ImageWidth,sizeof(ImageWidth),1,pFile);
51. fread(&ImageHeight,sizeof(ImageHeight),1,pFile);
52. //计算像素数据长度
53. PixelLength = ImageWidth*3;
54. while(PixelLength%4 != 0)
55. ++PixelLength;
56. PixelLength *= ImageHeight;
57. //读取像素数据
58. PixelData = (GLubyte*)malloc(PixelLength);
59. if(PixelData == 0)
60. exit(0);
61. fseek(pFile,54,SEEK_SET);
62. fread(PixelData,PixelLength,1,pFile);
63. //关闭文件
64. fclose(pFile);
65. //初始化GLUT并运行
66. glutInit(&argc,argv);
67. glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
68. glutInitWindowPosition(200,200);
69. glutInitWindowSize(ImageWidth,ImageHeight);
70. glutCreateWindow(FileName);
71. glutDisplayFunc(&display);
72. glutMainLoop();
73. free(PixelData);
74. return 0;
75. }</span></strong></pre>
76. <p></p>
77. <p><img src="http://img.my.csdn.net/uploads/201210/27/1351343956_5014.png" alt=""><br>
78. </p>
79. <p><strong><span style="font-size:18px"><br>
80. </span></strong></p>
81. <p><strong><span style="font-size:18px">31 像素的拷贝<span style="color:rgb(0,0,255); font-family:georgia,Verdana,Helvetica,Arial; line-height:19px; text-indent:26px">glCopyPixels（）--坐标点坐标，宽度值、高度值、GL_COLOR</span></span></strong></p>
82. <p></p>
83. <pre name="code" class="cpp"><span style="font-size:18px;"><strong>#include<GL/glut.h>
84. #include<iostream>
85. using namespace std;
86. #define WindowWidth 400
87. #define WindowHeight 400
88. /*函数grab
89. * 抓取窗口中的像素
90. * 假设窗口宽度为WindowWidth，高度为WindowHeight
91. */
92. #define BMP_Header_Length 54
93. void grap()
94. {
95. FILE* pDummyFile;
96. FILE* pWritingFile;
97. GLubyte* pPixelData;
98. GLubyte BMP_Header[BMP_Header_Length];
99. GLint i, j;
100. GLint PixelDataLength;
101. //计算像素数据的实际长度
102. i = WindowWidth * 3;  //得到每一行的像素数据长度
103. while(i%4 != 0)   //补充数据知道i是4的倍数
104. ++i;          //本来还有更快的算法，但这里追求直观，对速度没有太高要求
105. PixelDataLength = i*WindowHeight; //内存字节大小
106. //分配内存和打开文件
107. pPixelData = (GLubyte*)malloc(PixelDataLength);
108. if(pPixelData == 0)
109. exit(0);
110. pDummyFile = fopen("dummy.bmp", "rb");
111. if(pDummyFile == 0)
112. exit(0);
113. pWritingFile = fopen("grab.bmp", "wb");
114. if(pWritingFile == 0)
115. exit(0);
116. //读取像素
117. glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
118. glReadPixels(0,0,WindowWidth, WindowHeight,
119. GL_BGR_EXT,GL_UNSIGNED_BYTE,pPixelData);
120. //把dummy.bmp的头文件复制为新文件的文件头
121. fread(BMP_Header,sizeof(BMP_Header),1,pDummyFile);
122. fwrite(BMP_Header,sizeof(BMP_Header),1,pWritingFile);
123. fseek(pWritingFile,0x0012,SEEK_SET);
124. i = WindowWidth;
125. j = WindowHeight;
126. fwrite(&i,sizeof(i),1,pWritingFile);
127. fwrite(&j,sizeof(j),1,pWritingFile);
128. //写入像素数据
129. fseek(pWritingFile,0,SEEK_END);
130. fwrite(pPixelData,PixelDataLength,1,pWritingFile);
131. //释放内存和关闭文件
132. fclose(pDummyFile);
133. fclose(pWritingFile);
134. free(pPixelData);
135. }
136. void myDisplay()
137. {
138. glClear(GL_COLOR_BUFFER_BIT);
139. glBegin(GL_TRIANGLES);
140. glColor3f(1.0,0.0,0.0); glVertex2f(0.0f,0.0f);
141. glColor3f(0.0,1.0,0.0); glVertex2f(1.0f,0.0f);
142. glColor3f(0.0,0.0,1.0); glVertex2f(0.5f,1.0f);
143. glEnd();
144. glPixelZoom(-0.5f,-0.5f);
145. glRasterPos2i(1,1);
146. glCopyPixels(WindowWidth/2,WindowHeight/2,
147. WindowWidth/2,WindowHeight/2,GL_COLOR);
148. glutSwapBuffers();
149. grap();
150. }
151. void myIdle()
152. {
153. cout<<"doing"<<endl;
154. grap();
155. return;
156. }
157. int main(int argc, char* argv[])
158. {
159. glutInit(&argc, argv);
160. glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
161. glutInitWindowPosition(400,400);
162. glutInitWindowSize(400,400);
163. glutCreateWindow("Study04");
164. glutDisplayFunc(&myDisplay);
165. glutMainLoop();
166. cout<<"ok"<<endl;
167. return 0;
168. }</strong></span></pre>
169. <p></p>
170. <p><span style="font-size:18px"><strong><img src="http://img.my.csdn.net/uploads/201210/27/1351343928_8023.png" alt=""></strong></span></p>
171. <p><span style="font-size:18px"><strong>10.20 纹理测试</strong></span></p>
172. <p><span style="font-size:18px"><strong>32.1<span style="font-family:georgia,Verdana,Helvetica,Arial; line-height:19px; text-indent:26px; background-color:rgb(255,255,255)">纹理的使用方法，只要指定每一个顶点在纹理图象中所对应的像素位置，OpenGL就会自动计算顶点以外的其它点在纹理图象中所对应的像素位置</span></strong></span></p>
173. <p><span style="font-size:18px"><strong></strong></span></p>
174. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#define WindowWidth 400
175. #define WindowHeight 400
176. #define WindowTitle "OpenGL纹理测试"
177. #include<GL/glut.h>
178. #include<stdio.h>
179. #include<stdlib.h>
180. /*函数grap
181. *抓取窗口中的像素
182. *假设窗口宽度为WindowWidth，高度为WindowHeight
183. */
184. #define BMP_Header_Length 54
185. void grap()
186. {
187. FILE* pDummyFile;
188. FILE* pWritingFile;
189. GLubyte* pPixelData;
190. GLubyte BMP_Header[BMP_Header_Length];
191. GLint i,j;
192. GLint PixelDataLength;
193. //计算像素数据的实际长度
194. i = WindowWidth * 3;  //得到每一行的像素数据长度
195. while(i%4 == 0)
196. ++i;
197. PixelDataLength = i * WindowHeight;
198. //分配内存和打开文件
199. pPixelData = (GLubyte*)malloc(PixelDataLength);
200. if(pPixelData == 0)
201. exit(0);
202. pDummyFile = fopen("dummy.bmp","rb");
203. if(pDummyFile == 0)
204. exit(0);
205. pWritingFile = fopen("grap.bmp","wb");
206. if(pWritingFile == 0)
207. exit(0);
208. //读取像素
209. glPixelStorei(GL_UNPACK_ALIGNMENT,4);
210. glReadPixels(0,0,WindowWidth,WindowHeight,
211. GL_BGR_EXT,GL_UNSIGNED_BYTE,pPixelData);
212. //把dummy.bmp的文件头复制为新文件的文件头
213. fread(BMP_Header,sizeof(BMP_Header),1,pDummyFile);
214. fwrite(BMP_Header,sizeof(BMP_Header),1,pWritingFile);
215. fseek(pWritingFile,0x0012,SEEK_SET);
216. i = WindowWidth;
217. j = WindowHeight;
218. fwrite(&i,sizeof(i),1,pWritingFile);
219. fwrite(&j,sizeof(j),1,pWritingFile);
220. //写入像素数据
221. fseek(pWritingFile,54,SEEK_SET);
222. fwrite(pPixelData,PixelDataLength,1,pWritingFile);
223. //释放内存并关闭文件
224. fclose(pDummyFile);
225. fclose(pWritingFile);
226. free(pPixelData);
227. }
228. /* 函数power_of_two
229. * 检查一个整数是否为2的整数次方，如果是，返回1，否则返回0
230. * 实际上只要查看其二进制位中有多少个1，如果正好有1个，返回1，否则返回0
231. * 在“查看其二进制位中有多少个”时使用了一个小技巧
232. * 使用n &= （n-1）可以使得n中的减少一个
233. */
234. int power_of_two(int n)
235. {
236. if(n <= 0)
237. return 0;
238. return (n&(n-1)) == 0;
239. }
240. /* 函数load_texture
241. * 读取一个BMP文件作为纹理
242. * 如果失败，返回0，如果成功，返回纹理编号
243. */
244. GLuint load_texture(const char* file_name)
245. {
246. GLint width,height,total_bytes;
247. GLubyte* pixels=0;
248. GLuint last_texture_ID,texture_ID=0;
249. //打开文件，如果失败，返回
250. FILE* pFile=fopen(file_name,"rb");
251. if(pFile == 0)
252. return 0;
253. //读取文件中图像的宽度和高度
254. fseek(pFile,0x0012,SEEK_SET);
255. fread(&width,4,1,pFile);
256. fread(&height,4,1,pFile);
257. fseek(pFile,BMP_Header_Length,SEEK_SET);
258. //计算每行像素所占的字节数，并根据此数据计算总像素字节数
259. {
260. GLint line_bytes = width*3;
261. while(line_bytes % 4  !=  0)
262. ++line_bytes;
263. total_bytes = line_bytes*height;
264. }
265. //根据总像素字节数分配内存
266. pixels = (GLubyte*)malloc(total_bytes);
267. if(pixels == 0)
268. {
269. fclose(pFile);
270. return 0;
271. }
272. //读取像素数据
273. if(fread(pixels,total_bytes,1,pFile) <= 0)
274. {
275. free(pixels);
276. fclose(pFile);
277. return 0;
278. }
279. //在旧版本的OpenGL中
280. //如果图像宽度和高度不是2的整数次方，则需要进行缩放
281. //这里并没有检查openGL版本，出于对版本兼容性的考虑，按旧版本处理
282. //另外，无论是旧版本还是新版本
283. //当图像的宽度和高度超过当前openGL实现所支持的最大值时，也要进行缩放
284. {
285. GLint max;
286. glGetIntegerv(GL_MAX_TEXTURE_SIZE,&max);
287. if(!power_of_two(width) || !power_of_two(height) || width>max || height>max)
288. {
289. const GLint new_width = 256;
290. const GLint new_height = 256; //规定缩放后新的大小为256的正方形
291. GLint new_line_bytes,new_total_bytes;
292. GLubyte* new_pixels=0;
293. //计算每行所需要的字节数和总字节数
294. new_line_bytes = new_width * 3;
295. while(new_line_bytes % 4  != 0)
296. ++new_line_bytes;
297. new_total_bytes = new_line_bytes * new_height;
298. //分配内存
299. new_pixels = (GLubyte*)malloc(new_total_bytes);
300. if(new_pixels == 0)
301. {
302. free(pixels);
303. fclose(pFile);
304. return 0;
305. }
306. //进行像素缩放
307. gluScaleImage(GL_RGB,
308. width,height,GL_UNSIGNED_BYTE,pixels,
309. new_width,new_height,GL_UNSIGNED_BYTE,new_pixels);
310. //释放原来的像素数据，把pixels指向新的像素数据，并重新设置width和height
311. free(pixels);
312. pixels = new_pixels;
313. width = new_width;
314. height = new_height;
315. }
316. }
317. //分配一个新的纹理编号
318. glGenTextures(1,&texture_ID);
319. if(texture_ID == 0)
320. {
321. free(pixels);
322. fclose(pFile);
323. return 0;
324. }
325. //绑定新的纹理，载入纹理并设置纹理参数
326. //在绑定前，先获得原来绑定的纹理编号，以便在最后进行恢复
327. glGetIntegerv(GL_TEXTURE_BINDING_2D,(int*)&last_texture_ID);
328. glBindTexture(GL_TEXTURE_2D,texture_ID);
329. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR);
330. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
331. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_REPEAT);
332. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_REPEAT);
333. glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,width,height,0,
334. GL_BGR_EXT,GL_UNSIGNED_BYTE,pixels);
335. glBindTexture(GL_TEXTURE_2D,last_texture_ID);
336. //之前为pixels分配的内存可在使用glTexImage2D后释放
337. //因为此时像素数据已经被openGL另行保存了一份（可能被保存在专门的图形硬件中）
338. free(pixels);
339. return texture_ID;
340. }
341. /* 两个纹理对象的编号
342. */
343. GLuint texGround;
344. GLuint texWall;
345. void display()
346. {
347. //清除屏幕
348. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
349. //设置视角
350. glMatrixMode(GL_PROJECTION);
351. glLoadIdentity();
352. gluPerspective(75,1,1,21);
353. glMatrixMode(GL_MODELVIEW);
354. glLoadIdentity();
355. gluLookAt(1,5,5,0,0,0,0,0,1);
356. //使用“地”纹理绘制土地
357. glBindTexture(GL_TEXTURE_2D,texWall);
358. glBegin(GL_QUADS);
359. glTexCoord2f(0.0f,0.0f); glVertex3f(-8.0f,-8.0f,0.0f);
360. glTexCoord2f(0.0f,5.0f); glVertex3f(-8.0f,8.0f,0.0f);
361. glTexCoord2f(5.0f,5.0f); glVertex3f(8.0f,8.0f,0.0f);
362. glTexCoord2f(5.0f,0.0f); glVertex3f(8.0f,-8.0f,0.0f);
363. glEnd();
364. //使用“墙”纹理绘制栅栏
365. glBindTexture(GL_TEXTURE_2D,texWall);
366. glBegin(GL_QUADS);
367. glTexCoord2f(0.0f,0.0f); glVertex3f(-6.0f,-3.0f,0.0f);
368. glTexCoord2f(0.0f,1.0f); glVertex3f(-6.0f,-3.0f,1.5f);
369. glTexCoord2f(5.0f,1.0f); glVertex3f(6.0f,-3.0f,1.5f);
370. glTexCoord2f(5.0f,0.0f); glVertex3f(6.0f,-3.0f,0.0f);
371. glEnd();
372. //旋转后再绘制一个
373. glRotatef(-90,0,0,1);
374. glBegin(GL_QUADS);
375. glTexCoord2f(0.0f,0.0f); glVertex3f(-6.0f,-3.0f,0.0f);
376. glTexCoord2f(0.0f,1.0f); glVertex3f(-6.0f,-3.0f,1.5f);
377. glTexCoord2f(5.0f,1.0f); glVertex3f(6.0f,-3.0f,1.5f);
378. glTexCoord2f(5.0f,0.0f); glVertex3f(6.0f,-3.0f,0.0f);
379. glEnd();
380. //交换缓冲区，并保存像素数据到文件
381. glutSwapBuffers();
382. grap();
383. }
384. int main(int argc, char* argv[])
385. {
386. glutInit(&argc,argv);
387. glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
388. glutInitWindowPosition(200,200);
389. glutInitWindowSize(WindowWidth,WindowHeight);
390. glutCreateWindow(WindowTitle);
391. glutDisplayFunc(&display);
392. //在这里做一些初始化
393. glEnable(GL_DEPTH_TEST);
394. glEnable(GL_TEXTURE_2D);
395. texGround = load_texture("ground.bmp");
396. texWall = load_texture("wall.bmp");
397. //开始显示
398. glutMainLoop();
399. return 0;
400. }</span></strong></pre><img src="http://img.my.csdn.net/uploads/201210/27/1351344610_2938.png" alt=""><br>
401. <p><br>
402. </p>
403. <p><strong><span style="font-size:18px">32 跟上个程序原理一样，上一个载入的都是墙的坐标，所以图像也不是很正确</span></strong></p>
404. <p></p>
405. <p><span style="font-size:18px"><strong></strong></span></p>
406. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#define WindowWidth 400
407. #define WindowHeight 400
408. #define WindowTitle "OpenGL纹理测试"
409. #include<GL/glut.h>
410. #include<stdio.h>
411. #include<stdlib.h>
412. /*函数grap
413. *抓取窗口中的像素
414. *假设窗口宽度为WindowWidth，高度为WindowHeight
415. */
416. #define BMP_Header_Length 54
417. void grap()
418. {
419. FILE* pDummyFile;
420. FILE* pWritingFile;
421. GLubyte* pPixelData;
422. GLubyte BMP_Header[BMP_Header_Length];
423. GLint i,j;
424. GLint PixelDataLength;
425. //计算像素数据的实际长度
426. i = WindowWidth * 3;  //得到每一行的像素数据长度
427. while(i%4 == 0)
428. ++i;
429. PixelDataLength = i * WindowHeight;
430. //分配内存和打开文件
431. pPixelData = (GLubyte*)malloc(PixelDataLength);
432. if(pPixelData == 0)
433. exit(0);
434. pDummyFile = fopen("dummy.bmp","rb");
435. if(pDummyFile == 0)
436. exit(0);
437. pWritingFile = fopen("grap.bmp","wb");
438. if(pWritingFile == 0)
439. exit(0);
440. //读取像素
441. glPixelStorei(GL_UNPACK_ALIGNMENT,4);
442. glReadPixels(0,0,WindowWidth,WindowHeight,
443. GL_BGR_EXT,GL_UNSIGNED_BYTE,pPixelData);
444. //把dummy.bmp的文件头复制为新文件的文件头
445. fread(BMP_Header,sizeof(BMP_Header),1,pDummyFile);
446. fwrite(BMP_Header,sizeof(BMP_Header),1,pWritingFile);
447. fseek(pWritingFile,0x0012,SEEK_SET);
448. i = WindowWidth;
449. j = WindowHeight;
450. fwrite(&i,sizeof(i),1,pWritingFile);
451. fwrite(&j,sizeof(j),1,pWritingFile);
452. //写入像素数据
453. fseek(pWritingFile,54,SEEK_SET);
454. fwrite(pPixelData,PixelDataLength,1,pWritingFile);
455. //释放内存并关闭文件
456. fclose(pDummyFile);
457. fclose(pWritingFile);
458. free(pPixelData);
459. }
460. /* 函数power_of_two
461. * 检查一个整数是否为2的整数次方，如果是，返回1，否则返回0
462. * 实际上只要查看其二进制位中有多少个1，如果正好有1个，返回1，否则返回0
463. * 在“查看其二进制位中有多少个”时使用了一个小技巧
464. * 使用n &= （n-1）可以使得n中的减少一个
465. */
466. int power_of_two(int n)
467. {
468. if(n <= 0)
469. return 0;
470. return (n&(n-1)) == 0;
471. }
472. /* 函数load_texture
473. * 读取一个BMP文件作为纹理
474. * 如果失败，返回0，如果成功，返回纹理编号
475. */
476. GLuint load_texture(const char* file_name)
477. {
478. GLint width,height,total_bytes;
479. GLubyte* pixels=0;
480. GLuint last_texture_ID,texture_ID=0;
481. //打开文件，如果失败，返回
482. FILE* pFile=fopen(file_name,"rb");
483. if(pFile == 0)
484. return 0;
485. //读取文件中图像的宽度和高度
486. fseek(pFile,0x0012,SEEK_SET);
487. fread(&width,4,1,pFile);
488. fread(&height,4,1,pFile);
489. fseek(pFile,BMP_Header_Length,SEEK_SET);
490. //计算每行像素所占的字节数，并根据此数据计算总像素字节数
491. {
492. GLint line_bytes = width*3;
493. while(line_bytes % 4  !=  0)
494. ++line_bytes;
495. total_bytes = line_bytes*height;
496. }
497. //根据总像素字节数分配内存
498. pixels = (GLubyte*)malloc(total_bytes);
499. if(pixels == 0)
500. {
501. fclose(pFile);
502. return 0;
503. }
504. //读取像素数据
505. if(fread(pixels,total_bytes,1,pFile) <= 0)
506. {
507. free(pixels);
508. fclose(pFile);
509. return 0;
510. }
511. //在旧版本的OpenGL中
512. //如果图像宽度和高度不是2的整数次方，则需要进行缩放
513. //这里并没有检查openGL版本，出于对版本兼容性的考虑，按旧版本处理
514. //另外，无论是旧版本还是新版本
515. //当图像的宽度和高度超过当前openGL实现所支持的最大值时，也要进行缩放
516. {
517. GLint max;
518. glGetIntegerv(GL_MAX_TEXTURE_SIZE,&max);
519. if(!power_of_two(width) || !power_of_two(height) || width>max || height>max)
520. {
521. const GLint new_width = 256;
522. const GLint new_height = 256; //规定缩放后新的大小为256的正方形
523. GLint new_line_bytes,new_total_bytes;
524. GLubyte* new_pixels=0;
525. //计算每行所需要的字节数和总字节数
526. new_line_bytes = new_width * 3;
527. while(new_line_bytes % 4  != 0)
528. ++new_line_bytes;
529. new_total_bytes = new_line_bytes * new_height;
530. //分配内存
531. new_pixels = (GLubyte*)malloc(new_total_bytes);
532. if(new_pixels == 0)
533. {
534. free(pixels);
535. fclose(pFile);
536. return 0;
537. }
538. //进行像素缩放
539. gluScaleImage(GL_RGB,
540. width,height,GL_UNSIGNED_BYTE,pixels,
541. new_width,new_height,GL_UNSIGNED_BYTE,new_pixels);
542. //释放原来的像素数据，把pixels指向新的像素数据，并重新设置width和height
543. free(pixels);
544. pixels = new_pixels;
545. width = new_width;
546. height = new_height;
547. }
548. }
549. //分配一个新的纹理编号
550. glGenTextures(1,&texture_ID);
551. if(texture_ID == 0)
552. {
553. free(pixels);
554. fclose(pFile);
555. return 0;
556. }
557. //绑定新的纹理，载入纹理并设置纹理参数
558. //在绑定前，先获得原来绑定的纹理编号，以便在最后进行恢复
559. glGetIntegerv(GL_TEXTURE_BINDING_2D,(int*)&last_texture_ID);
560. glBindTexture(GL_TEXTURE_2D,texture_ID);
561. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR);
562. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
563. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_REPEAT);
564. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_REPEAT);
565. glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,width,height,0,
566. GL_BGR_EXT,GL_UNSIGNED_BYTE,pixels);
567. glBindTexture(GL_TEXTURE_2D,last_texture_ID);
568. //之前为pixels分配的内存可在使用glTexImage2D后释放
569. //因为此时像素数据已经被openGL另行保存了一份（可能被保存在专门的图形硬件中）
570. free(pixels);
571. return texture_ID;
572. }
573. /* 两个纹理对象的编号
574. */
575. GLuint texGround;
576. GLuint texWall;
577. void display()
578. {
579. //清除屏幕
580. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
581. //设置视角
582. glMatrixMode(GL_PROJECTION);
583. glLoadIdentity();
584. gluPerspective(75,1,1,21);
585. glMatrixMode(GL_MODELVIEW);
586. glLoadIdentity();
587. gluLookAt(1,5,5,0,0,0,0,0,1);
588. //使用“地”纹理绘制土地
589. glBindTexture(GL_TEXTURE_2D,texGround);
590. glBegin(GL_QUADS);
591. glTexCoord2f(0.0f,0.0f); glVertex3f(-8.0f,-8.0f,0.0f);
592. glTexCoord2f(0.0f,5.0f); glVertex3f(-8.0f,8.0f,0.0f);
593. glTexCoord2f(5.0f,5.0f); glVertex3f(8.0f,8.0f,0.0f);
594. glTexCoord2f(5.0f,0.0f); glVertex3f(8.0f,-8.0f,0.0f);
595. glEnd();
596. //使用“墙”纹理绘制栅栏
597. glBindTexture(GL_TEXTURE_2D,texWall);
598. glBegin(GL_QUADS);
599. glTexCoord2f(0.0f,0.0f); glVertex3f(-6.0f,-3.0f,0.0f);
600. glTexCoord2f(0.0f,1.0f); glVertex3f(-6.0f,-3.0f,1.5f);
601. glTexCoord2f(5.0f,1.0f); glVertex3f(6.0f,-3.0f,1.5f);
602. glTexCoord2f(5.0f,0.0f); glVertex3f(6.0f,-3.0f,0.0f);
603. glEnd();
604. //旋转后再绘制一个
605. glRotatef(-90,0,0,1);
606. glBegin(GL_QUADS);
607. glTexCoord2f(0.0f,0.0f); glVertex3f(-6.0f,-3.0f,0.0f);
608. glTexCoord2f(0.0f,1.0f); glVertex3f(-6.0f,-3.0f,1.5f);
609. glTexCoord2f(5.0f,1.0f); glVertex3f(6.0f,-3.0f,1.5f);
610. glTexCoord2f(5.0f,0.0f); glVertex3f(6.0f,-3.0f,0.0f);
611. glEnd();
612. //交换缓冲区，并保存像素数据到文件
613. glutSwapBuffers();
614. grap();
615. }
616. int main(int argc, char* argv[])
617. {
618. glutInit(&argc,argv);
619. glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
620. glutInitWindowPosition(200,200);
621. glutInitWindowSize(WindowWidth,WindowHeight);
622. glutCreateWindow(WindowTitle);
623. glutDisplayFunc(&display);
624. //在这里做一些初始化
625. glEnable(GL_DEPTH_TEST);
626. glEnable(GL_TEXTURE_2D);
627. texGround = load_texture("ground.bmp");
628. texWall = load_texture("wall.bmp");
629. //开始显示
630. glutMainLoop();
631. return 0;
632. }</span></strong></pre><img src="http://img.my.csdn.net/uploads/201210/27/1351344918_9096.png" alt=""><br>
633. <p><br>
634. </p>
635. <p><strong><span style="font-size:18px">33.alpha测试</span></strong></p>
636. <p></p>
637. <p></p>
638. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#define WindowWidth 400
639. #define WindowHeight 400
640. #define WindowTitle "OpenGL纹理测试"
641. #include<GL/glut.h>
642. #include<stdio.h>
643. #include<stdlib.h>
644. /*函数grap
645. *抓取窗口中的像素
646. *假设窗口宽度为WindowWidth，高度为WindowHeight
647. */
648. #define BMP_Header_Length 54
649. /* 函数power_of_two
650. * 检查一个整数是否为2的整数次方，如果是，返回1，否则返回0
651. * 实际上只要查看其二进制位中有多少个1，如果正好有1个，返回1，否则返回0
652. * 在“查看其二进制位中有多少个”时使用了一个小技巧
653. * 使用n &= （n-1）可以使得n中的减少一个
654. */
655. int power_of_two(int n)
656. {
657. if(n <= 0)
658. return 0;
659. return (n&(n-1)) == 0;
660. }
661. /* 函数load_texture
662. * 读取一个BMP文件作为纹理
663. * 如果失败，返回0，如果成功，返回纹理编号
664. */
665. GLuint load_texture(const char* file_name)
666. {
667. GLint width,height,total_bytes;
668. GLubyte* pixels=0;
669. GLuint last_texture_ID,texture_ID=0;
670. //打开文件，如果失败，返回
671. FILE* pFile=fopen(file_name,"rb");
672. if(pFile == 0)
673. return 0;
674. //读取文件中图像的宽度和高度
675. fseek(pFile,0x0012,SEEK_SET);
676. fread(&width,4,1,pFile);
677. fread(&height,4,1,pFile);
678. fseek(pFile,BMP_Header_Length,SEEK_SET);
679. //计算每行像素所占的字节数，并根据此数据计算总像素字节数
680. {
681. GLint line_bytes = width*3;
682. while(line_bytes % 4  !=  0)
683. ++line_bytes;
684. total_bytes = line_bytes*height;
685. }
686. //根据总像素字节数分配内存
687. pixels = (GLubyte*)malloc(total_bytes);
688. if(pixels == 0)
689. {
690. fclose(pFile);
691. return 0;
692. }
693. //读取像素数据
694. if(fread(pixels,total_bytes,1,pFile) <= 0)
695. {
696. free(pixels);
697. fclose(pFile);
698. return 0;
699. }
700. //在旧版本的OpenGL中
701. //如果图像宽度和高度不是2的整数次方，则需要进行缩放
702. //这里并没有检查openGL版本，出于对版本兼容性的考虑，按旧版本处理
703. //另外，无论是旧版本还是新版本
704. //当图像的宽度和高度超过当前openGL实现所支持的最大值时，也要进行缩放
705. {
706. GLint max;
707. glGetIntegerv(GL_MAX_TEXTURE_SIZE,&max);
708. if(!power_of_two(width) || !power_of_two(height) || width>max || height>max)
709. {
710. const GLint new_width = 256;
711. const GLint new_height = 256; //规定缩放后新的大小为256的正方形
712. GLint new_line_bytes,new_total_bytes;
713. GLubyte* new_pixels=0;
714. //计算每行所需要的字节数和总字节数
715. new_line_bytes = new_width * 3;
716. while(new_line_bytes % 4  != 0)
717. ++new_line_bytes;
718. new_total_bytes = new_line_bytes * new_height;
719. //分配内存
720. new_pixels = (GLubyte*)malloc(new_total_bytes);
721. if(new_pixels == 0)
722. {
723. free(pixels);
724. fclose(pFile);
725. return 0;
726. }
727. //进行像素缩放
728. gluScaleImage(GL_RGB,
729. width,height,GL_UNSIGNED_BYTE,pixels,
730. new_width,new_height,GL_UNSIGNED_BYTE,new_pixels);
731. //释放原来的像素数据，把pixels指向新的像素数据，并重新设置width和height
732. free(pixels);
733. pixels = new_pixels;
734. width = new_width;
735. height = new_height;
736. }
737. }
738. //分配一个新的纹理编号
739. glGenTextures(1,&texture_ID);
740. if(texture_ID == 0)
741. {
742. free(pixels);
743. fclose(pFile);
744. return 0;
745. }
746. //绑定新的纹理，载入纹理并设置纹理参数
747. //在绑定前，先获得原来绑定的纹理编号，以便在最后进行恢复
748. glGetIntegerv(GL_TEXTURE_BINDING_2D,(int*)&last_texture_ID);
749. glBindTexture(GL_TEXTURE_2D,texture_ID);
750. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR);
751. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
752. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_REPEAT);
753. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_REPEAT);
754. glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,width,height,0,
755. GL_BGR_EXT,GL_UNSIGNED_BYTE,pixels);
756. glBindTexture(GL_TEXTURE_2D,last_texture_ID);
757. //之前为pixels分配的内存可在使用glTexImage2D后释放
758. //因为此时像素数据已经被openGL另行保存了一份（可能被保存在专门的图形硬件中）
759. free(pixels);
760. return texture_ID;
761. }
762. /* 将当前纹理BGR格式转换为BGRA格式
763. * 纹理中像素的RGB值如果与指定rgb相差不超过absolute，则将Alpha设置为0.0，否则设置为1.0
764. */
765. void texture_colorKey(GLubyte r,GLubyte g,GLubyte b,GLubyte absolute)
766. {
767. GLint width,height;
768. GLubyte* pixels=0;
769. //获得纹理的大小信息
770. glGetTexLevelParameteriv(GL_TEXTURE_2D,0,GL_TEXTURE_WIDTH,&width);
771. glGetTexLevelParameteriv(GL_TEXTURE_2D,0,GL_TEXTURE_HEIGHT,&height);
772. //分配空间并获得纹理像素
773. pixels = (GLubyte*)malloc(width*height*4);
774. if(pixels == 0)
775. return;
776. glGetTexImage(GL_TEXTURE_2D,0,GL_BGRA_EXT,GL_UNSIGNED_BYTE,pixels);
777. //修改像素中的Alpha值
778. //其中pixels[i*4],pixels[i*4+1],pixels[i*4+2],pixels[i*4+3]
779. //分别表示第i个像素的蓝、绿、红、Alpha四种分量，0表示最小，255表示最大
780. {
781. GLint i;
782. GLint count = width*height;
783. for(i=0;i<count;++i)
784. {
785. if(abs(pixels[i*4]-b) <= absolute
786. && abs(pixels[i*4+1]-g) <= absolute
787. && abs(pixels[i*4+2]-r) <= absolute)
788. pixels[i*4+3] = 0;
789. else
790. pixels[i*4+3] = 255;
791. }
792. }
793. //将修改后的像素重新设置到纹理中，释放内存
794. glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,width,height,0,
795. GL_BGRA_EXT,GL_UNSIGNED_BYTE,pixels);
796. free(pixels);
797. }
798. void display()
799. {
800. static int initialized=0;
801. static GLuint texWindow=0;
802. static GLuint texPicture=0;
803. //执行初始化操作，包括：读取相片，读取相框，将相框由BGR颜色转换为BGRA，
804. //启用二维纹理
805. if(!initialized)
806. {
807. texPicture = load_texture("picture.bmp");
808. texWindow = load_texture("window.bmp");
809. glBindTexture(GL_TEXTURE_2D,texWindow);
810. texture_colorKey(255,255,255,10);
811. glEnable(GL_TEXTURE_2D);
812. initialized = 1;
813. }
814. glClear(GL_COLOR_BUFFER_BIT);
815. //绘制相片，此时不需要进行Alpha测试，所有的像素都进行绘制
816. glBindTexture(GL_TEXTURE_2D,texPicture);
817. glDisable(GL_ALPHA_TEST);
818. glBegin(GL_QUADS);
819. glTexCoord2f(0,0);  glVertex2f(-1.0f,-1.0f);
820. glTexCoord2f(0,1);  glVertex2f(-1.0f,1.0f);
821. glTexCoord2f(1,1);  glVertex2f(1.0f,1.0f);
822. glTexCoord2f(1,0);  glVertex2f(1.0f,-1.0f);
823. glEnd();
824. //绘制相框，此时进行Alpha测试，只绘制不透明部分的像素
825. glBindTexture(GL_TEXTURE_2D,texWindow);
826. glEnable(GL_ALPHA_TEST);
827. glAlphaFunc(GL_GREATER,0.5f);
828. glBegin(GL_QUADS);
829. glTexCoord2f(0,0);  glVertex2f(-1.0f,-1.0f);
830. glTexCoord2f(0,1);  glVertex2f(-1.0f,1.0f);
831. glTexCoord2f(1,1);  glVertex2f(1.0f,1.0f);
832. glTexCoord2f(1,0);  glVertex2f(1.0f,-1.0f);
833. glEnd();
834. //交换缓冲
835. glutSwapBuffers();
836. }
837. int main(int argc, char* argv[])
838. {
839. glutInit(&argc,argv);
840. glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
841. glutInitWindowPosition(200,200);
842. glutInitWindowSize(WindowWidth,WindowHeight);
843. glutCreateWindow("alpha-test");
844. glutDisplayFunc(&display);
845. //开始显示
846. glutMainLoop();
847. return 0;
848. }</span></strong></pre><span style="font-size:18px"><strong><img src="http://img.my.csdn.net/uploads/201210/27/1351345099_4328.png" alt=""><br>
849. </strong></span>
850. <p></p>
851. <p></p>
852. <p><span style="font-size:18px"><strong>10.21</strong></span></p>
853. <p><span style="font-size:18px"><strong>34. 模版测试。我的测试失败，具体的写法可以参考开头给的网址。</strong></span></p>
854. <p><span style="font-size:18px"><strong></strong></span></p>
855. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#include<GL/glut.h>
856. void draw_sphere()
857. {
858. //设置光源
859. glEnable(GL_LIGHTING);
860. glEnable(GL_LIGHT0);
861. {
862. GLfloat
863. pos[] = {5.0f,5.0f,0.0f,1.0f},
864. ambient[] = {0.0f,0.0f,1.0f,1.0f};
865. glLightfv(GL_LIGHT0,GL_POSITION,pos);
866. glLightfv(GL_LIGHT0,GL_AMBIENT,ambient);
867. }
868. //绘制一个球体
869. glColor3f(1,0,0);
870. glPushMatrix();
871. glTranslatef(0,0,2);
872. glutSolidSphere(0.5,20,20);
873. glPopMatrix();
874. }
875. void display()
876. {
877. glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
878. //设置观察点
879. glMatrixMode(GL_PROJECTION);  //采用投影矩阵
880. glLoadIdentity();
881. gluPerspective(60,1,5,25);  //投影区域，角度，宽高比，近距离，远距离
882. glMatrixMode(GL_MODELVIEW); //采用模型矩阵
883. glLoadIdentity();
884. gluLookAt(5,0,6.5,0,0,0,0,1,0);
885. glEnable(GL_DEPTH_TEST);
886. //绘制球体
887. //glDisable(GL_STENCIL_TEST);
888. draw_sphere();
889. //绘制一个平面镜。在绘制的同时注意设置模版缓冲
890. //另外，为了保证平面镜之后的镜像能够正确绘制，在绘制平面
891. //镜像时需要将深度缓冲区设置为只读的。
892. //在绘制时暂时关闭光照效果
893. glClearStencil(0);
894. glClear(GL_STENCIL_BUFFER_BIT);
895. glStencilFunc(GL_ALWAYS,1,0xFF);
896. glStencilOp(GL_KEEP,GL_KEEP,GL_REPLACE);
897. glEnable(GL_STENCIL_TEST);
898. glDisable(GL_LIGHTING);
899. glColor3f(0.5f,0.5f,0.5f);
900. glDepthMask(GL_FALSE);
901. glRectf(-1.5f,-1.5f,1.5f,1.5f);
902. glDepthMask(GL_TRUE);
903. //绘制一个与先前球体关于平面镜对称的球体，注意光源的位置也要发生对称改变
904. //因为平面镜是在X轴和Y轴所确定的平面，所以只要Z坐标取反即可实现对称
905. //为了保证球体的绘制范围被限制在平面镜内部，使用模版测试
906. glEnable(GL_STENCIL_TEST);
907. glStencilFunc(GL_EQUAL,1,0xFF);
908. glStencilOp(GL_KEEP,GL_KEEP,GL_REPLACE);
909. glScalef(1.0f,1.0f,-1.0f);
910. draw_sphere();
911. //交换缓冲
912. glutSwapBuffers();
913. }
914. int main(int argc, char* argv[])
915. {
916. glutInit(&argc,argv);
917. glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
918. glutInitWindowPosition(200,200);
919. glutInitWindowSize(400,400);
920. glutCreateWindow("study");
921. glutDisplayFunc(&display);
922. glutMainLoop();
923. return 0;
924. }</span></strong></pre><img src="http://img.my.csdn.net/uploads/201210/27/1351345241_6397.png" alt=""><br>
925. <p></p>
926. <p><span style="font-size:18px"><strong>35 这题只敲了代码，没插件就没有运行，也没有图，具体大家可以看开头的网址</strong></span></p>
927. <p></p>
928. <pre name="code" class="cpp"><span style="font-size:18px;"><strong>//#include"GLee.h"
929. #include<GL/glut.h>
930. #include<stdio.h>
931. void display()
932. {
933. glClear(GL_COLOR_BUFFER_BIT);
934. //if(GLEE_ARB_window_pos)
935. //{//如果支持GL_ARB_window_pos
936. //则使用glWindowPos2iARB函数，指定绘制位置
937. //  printf("支持GL_ARB_window_pos\n");
938. //  printf("使用glWindowPos函数\n");
939. //  glWindowPos2iARB(100,100);
940. //  }else{
941. GLint viewport[4];
942. GLdouble modelview[16],projection[16];
943. GLdouble x, y, z;
944. printf("不支持GL_ARB_window_pos\n");
945. printf("使用glRasterPos函数\n");
946. glGetIntegerv(GL_VIEWPORT,viewport);
947. glGetDoublev(GL_MODELVIEW_MATRIX,modelview);
948. glGetDoublev(GL_PROJECTION_MATRIX,projection);
949. gluUnProject(100,100,0.5,modelview,projection,viewport,&x,&y,&z);
950. glRasterPos3d(x,y,z);
951. //  }
952. {//绘制一个5*5的像素块
953. GLubyte pixels[5][4][4];
954. //把像素中的所有像素都设置为红色
955. int i,j;
956. for(i=0;i<5;++i)
957. for(j=0;j<5;++j)
958. {
959. pixels[i][j][0] = 255;
960. pixels[i][j][1] = 0;
961. pixels[i][j][2] = 0;
962. pixels[i][j][3] = 255;
963. }
964. glDrawPixels(5,5,GL_RGBA,GL_UNSIGNED_BYTE,pixels);
965. }
966. glutSwapBuffers();
967. }
968. int main(int argc,char* argv[])
969. {
970. glutInit(&argc,argv);
971. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
972. glutInitWindowPosition(100,100);
973. glutInitWindowSize(512,512);
974. glutCreateWindow("OpenGL");
975. glutDisplayFunc(&display);
976. glutMainLoop();
977. return 0;
978. }</strong></span></pre>
979. <p></p>
980. <p><span style="font-size:18px"><strong>36 显示字体 用的显示列表</strong></span></p>
981. <p><span style="font-size:18px"><strong></strong></span></p>
982. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#include<GL/glut.h>
983. #include<windows.h>
984. //ASCII字符总共只有0到127，一共128种字符
985. #define MAX_CHAR 128
986. void drawString(const char* str)
987. {
988. static int isFirstCall = 1;
989. static GLuint lists;
990. if(isFirstCall){//如果是第一次调用，执行初始化
991. //为每一个ASCII字符产生一个显示列表
992. isFirstCall = 0;
993. //申请MAX_CHAR个连续的显示列表编号
994. lists = glGenLists(MAX_CHAR);
995. //把每个字符的绘制命令都装到对应的显示列表中
996. wglUseFontBitmaps(wglGetCurrentDC(),0,MAX_CHAR,lists);
997. //调用每个字符对应的显示列表，绘制每个字符
998. for(;*str!=‘\0‘;++str)
999. glCallList(lists + *str);
1000. }
1001. }
1002. void display()
1003. {
1004. glClear(GL_COLOR_BUFFER_BIT);
1005. glColor3f(1.0f,0.0f,0.0f);
1006. glRasterPos2f(0.0f,0.0f);
1007. drawString("hello,world");
1008. glutSwapBuffers();
1009. }
1010. int main(int argc,char* argv[])
1011. {
1012. glutInit(&argc,argv);
1013. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
1014. glutInitWindowPosition(100,100);
1015. glutInitWindowSize(512,512);
1016. glutCreateWindow("OpenGL");
1017. glutDisplayFunc(&display);
1018. glutMainLoop();
1019. return 0;
1020. }</span></strong></pre><img src="http://img.my.csdn.net/uploads/201210/27/1351345370_9989.png" alt=""><br>
1021. <p></p>
1022. <p><span style="font-size:18px"><strong>37 字体设置</strong></span></p>
1023. <p><span style="font-size:18px"><strong></strong></span></p>
1024. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#include<GL/glut.h>
1025. #include<windows.h>
1026. //ASCII字符总共只有0到127，一共128种字符
1027. #define MAX_CHAR 128
1028. void drawString(const char* str)
1029. {
1030. static int isFirstCall = 1;
1031. static GLuint lists;
1032. if(isFirstCall){//如果是第一次调用，执行初始化
1033. //为每一个ASCII字符产生一个显示列表
1034. isFirstCall = 0;
1035. //申请MAX_CHAR个连续的显示列表编号
1036. lists = glGenLists(MAX_CHAR);
1037. //把每个字符的绘制命令都装到对应的显示列表中
1038. wglUseFontBitmaps(wglGetCurrentDC(),0,MAX_CHAR,lists);
1039. //调用每个字符对应的显示列表，绘制每个字符
1040. for(;*str!=‘\0‘;++str)
1041. glCallList(lists + *str);
1042. }
1043. }
1044. void selectFont(int size,int charset,const char* face){
1045. HFONT hFont=CreateFontA(size,0,0,0,FW_MEDIUM,0,0,0,
1046. charset,OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,
1047. DEFAULT_QUALITY,DEFAULT_PITCH | FF_SWISS,face);
1048. HFONT hOldFont = (HFONT)SelectObject(wglGetCurrentDC(),hFont);
1049. DeleteObject(hOldFont);
1050. }
1051. void display()
1052. {
1053. selectFont(48,ANSI_CHARSET,"Comic Sans MS");
1054. glClear(GL_COLOR_BUFFER_BIT);
1055. glColor3f(1.0f,0.0f,0.0f);
1056. glRasterPos2f(0.0f,0.0f);
1057. drawString("Hello,World!");
1058. glutSwapBuffers();
1059. }
1060. int main(int argc,char* argv[])
1061. {
1062. glutInit(&argc,argv);
1063. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
1064. glutInitWindowPosition(100,100);
1065. glutInitWindowSize(512,512);
1066. glutCreateWindow("OpenGL");
1067. glutDisplayFunc(&display);
1068. glutMainLoop();
1069. return 0;
1070. }</span></strong></pre><img src="http://img.my.csdn.net/uploads/201210/27/1351345437_6278.png" alt=""><br>
1071. <p></p>
1072. <p><span style="font-size:18px"><strong>38 显示汉字</strong></span></p>
1073. <p><span style="font-size:18px"><strong></strong></span></p>
1074. <pre name="code" class="cpp"><strong><span style="font-size:18px;">#include<GL/glut.h>
1075. #include<windows.h>
1076. //ASCII字符总共只有0到127，一共128种字符
1077. #define MAX_CHAR 128
1078. void drawCNString(const char* str)
1079. {
1080. int len,i;
1081. wchar_t* wstring;
1082. HDC hDC=wglGetCurrentDC();
1083. GLuint list = glGenLists(1);
1084. //计算字符个数
1085. //如果是双字节字符的（比如中文字符），两个字节才算一个字符
1086. //否则一个字节算一个字符
1087. len=0;
1088. for(i=0;str[i]!=‘\0‘;++i)
1089. {
1090. if(IsDBCSLeadByte(str[i]))
1091. ++i;
1092. ++len;
1093. }
1094. //将混合字符转化为宽字符
1095. wstring = (wchar_t*)malloc((len+1)*sizeof(wchar_t));
1096. MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,str,-1,wstring,len);
1097. wstring[len] = ‘\0‘;
1098. //逐个输出字符
1099. for(i=0;i<len;++i)
1100. {
1101. wglUseFontBitmapsW(hDC,wstring[i],1,list);
1102. glCallList(list);
1103. }
1104. //回收所有临时资源
1105. free(wstring);
1106. glDeleteLists(list,1);
1107. }
1108. void selectFont(int size,int charset,const char* face){
1109. HFONT hFont=CreateFontA(size,0,0,0,FW_MEDIUM,0,0,0,
1110. charset,OUT_DEFAULT_PRECIS,CLIP_DEFAULT_PRECIS,
1111. DEFAULT_QUALITY,DEFAULT_PITCH | FF_SWISS,face);
1112. HFONT hOldFont = (HFONT)SelectObject(wglGetCurrentDC(),hFont);
1113. DeleteObject(hOldFont);
1114. }
1115. void display()
1116. {
1117. glClear(GL_COLOR_BUFFER_BIT);
1118. selectFont(48,ANSI_CHARSET,"Comic Sans MS");
1119. glColor3f(1.0f,0.0f,0.0f);
1120. glRasterPos2f(-0.7f,0.4f);
1121. drawCNString("Hello,World!");
1122. selectFont(48,GB2312_CHARSET,"楷体_GB2312");
1123. glColor3f(1.0f,1.0f,0.0f);
1124. glRasterPos2f(-0.7f,-0.1f);
1125. drawCNString("当代中国汉字");
1126. selectFont(48,GB2312_CHARSET,"华文仿宋");
1127. glColor3f(0.0f,1.0f,0.0f);
1128. glRasterPos2f(-0.7f,-0.6f);
1129. drawCNString("傳統中國漢字");
1130. glutSwapBuffers();
1131. }
1132. int main(int argc,char* argv[])
1133. {
1134. glutInit(&argc,argv);
1135. glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
1136. glutInitWindowPosition(100,100);
1137. glutInitWindowSize(512,512);
1138. glutCreateWindow("OpenGL");
1139. glutDisplayFunc(&display);
1140. glutMainLoop();
1141. return 0;
1142. }</span></strong></pre><img src="http://img.my.csdn.net/uploads/201210/27/1351345485_1205.png" alt=""><br>
1143. <p></p>
1144. <p><span style="font-size:18px; color:#ff0000"><strong>OVER！</strong></span></p>
1145. <p><br>
1146. </p>