编写一个程序，该程序运行时可以用鼠标的一个按键调整立方体的方向，用另一个按键平移立方体，用第三个按键缩放立方体。
这是题目，我的程序不一定完全按照这个来。初学OpenGL，对那一堆坐标系表示十分混乱，慢慢看吧，有点头绪了。
（一）
1 #include <gl/glut.h>
2 #include <math.h>
3 #define GL_PI 3.1415f
4
5 GLfloat xRot = -35.0f;
6 GLfloat yRot = 15.0f;
7 GLfloat xMov = 0.0f;
8 GLfloat winW = 0.0f;
9 GLfloat winH = 0.0f;
10 GLfloat zoom = 1.0f;
11
12 void RenderScene(void)
13 {
14 glClear(GL_COLOR_BUFFER_BIT);
15
16 glPushMatrix();
17 glLoadIdentity();
18 glRotatef(xRot, 1.0f, 0.0f, 0.0f);
19 glRotatef(yRot, 0.0f, 1.0f, 0.0f);
20
21 // 底面
22 glBegin(GL_LINE_LOOP);
23 glVertex3f(0.0f+xMov, 0.0f, 0.0f);
24 glVertex3f(1.0f+xMov, 0.0f, 0.0f);
25 glVertex3f(1.0f+xMov, 0.0f, 1.0f);
26 glVertex3f(0.0f+xMov, 0.0f, 1.0f);
27 glEnd();
28
29 // 顶面
30 glBegin(GL_LINE_LOOP);
31 glVertex3f(0.0f+xMov, 1.0f, 1.0f);
32 glVertex3f(0.0f+xMov, 1.0f, 0.0f);
33 glVertex3f(1.0f+xMov, 1.0f, 0.0f);
34 glVertex3f(1.0f+xMov, 1.0f, 1.0f);
35 glEnd();
36
37 // 背面
38 glBegin(GL_LINE_LOOP);
39 glVertex3f(0.0f+xMov, 0.0f, 0.0f);
40 glVertex3f(1.0f+xMov, 0.0f, 0.0f);
41 glVertex3f(1.0f+xMov, 1.0f, 0.0f);
42 glVertex3f(0.0f+xMov, 1.0f, 0.0f);
43 glEnd();
44
45 // 前面
46 glBegin(GL_LINE_LOOP);
47 glVertex3f(1.0f+xMov, 0.0f, 1.0f);
48 glVertex3f(0.0f+xMov, 0.0f, 1.0f);
49 glVertex3f(0.0f+xMov, 1.0f, 1.0f);
50 glVertex3f(1.0f+xMov, 1.0f, 1.0f);
51 glEnd();
52
53 // 右面
54 glBegin(GL_LINE_LOOP);
55 glVertex3f(1.0f+xMov, 0.0f, 0.0f);
56 glVertex3f(1.0f+xMov, 0.0f, 1.0f);
57 glVertex3f(1.0f+xMov, 1.0f, 1.0f);
58 glVertex3f(1.0f+xMov, 1.0f, 0.0f);
59 glEnd();
60
61 // 左面
62 glBegin(GL_LINE_LOOP);
63 glVertex3f(0.0f+xMov, 0.0f, 0.0f);
64 glVertex3f(0.0f+xMov, 0.0f, 1.0f);
65 glVertex3f(0.0f+xMov, 1.0f, 1.0f);
66 glVertex3f(0.0f+xMov, 1.0f, 0.0f);
67 glEnd();
68
69 glPopMatrix();
70 glFlush();
71 }
72 void OnReshape(int w, int h)
73 {
74 GLfloat aspectRatio = (GLfloat)w/(GLfloat)h;
75 winW = w;
76 winH = h;
77
78 glViewport(0,0,w,h);
79 glMatrixMode(GL_PROJECTION);
80 glLoadIdentity();
81 if (w <= h)
82 {
83 glOrtho(-3.0f*zoom, 3.0f*zoom, -3.0f*zoom/aspectRatio, 3.0f*zoom/aspectRatio, -10.0f*zoom, 10.0f*zoom);
84 }
85 else{
86 glOrtho(-3.0f*zoom*aspectRatio, 3.0f*zoom*aspectRatio, -3.0f*zoom, 3.0f*zoom, -10.0f*zoom, 10.0f*zoom);
87 }
88 glMatrixMode(GL_MODELVIEW);
89 glLoadIdentity();
90 }
91 void OnMouse(int button, int state, int x, int y)
92 {
93 if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
94 {
95 xRot += 1;
96 yRot += 1;
97 glutPostRedisplay();
98 }
99 else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
100 {
101 xMov -= 0.1;
102 glutPostRedisplay();
103 }
104 else if (button == GLUT_MIDDLE_BUTTON && state == GLUT_DOWN)
105 {
106 zoom += 0.1;
107 OnReshape(winW,winH);
108 glutPostRedisplay();
109 }
110 }
111 void OnKeyUpDown(int key, int x, int y)
112 {
113 if (key == GLUT_KEY_UP){
114 zoom -= 0.1;
115 }
116 else if (key == GLUT_KEY_DOWN){
117 zoom += 0.1;
118 }
119 OnReshape(winW,winH);
120 glutPostRedisplay();
121 }
122
123 void SetupRC()
124 {
125 glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
126 glColor3f(0.0f, 1.0f, 0.0f);
127 }
128
129 void main(int argc, char **argv)
130 {
131 glutInit(&argc,argv);
132 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
133 glutCreateWindow("Cube");
134 glutDisplayFunc(RenderScene);
135 glutReshapeFunc(OnReshape);
136 glutMouseFunc(OnMouse);
137 glutSpecialFunc(OnKeyUpDown);
138
139 SetupRC();
140
141 glutMainLoop();
142 }
这个程序略长，显得有点笨。手工实现了平移和放大缩小的功能，值得记录一下。
（二）
1 #include <windows.h>
2 #include<gl/glut.h>
3 #include <math.h>
4 #include<stdio.h>
5
6 GLfloat angle=0.0f;
7 GLfloat translate_x=0.0f;
8 GLfloat zoom=1.0f;
9
10 void myDisplay()
11 {
12 glClear (GL_COLOR_BUFFER_BIT);
13 glColor3f (1.0f, 1.0f, 1.0f);
14 glPushMatrix();
15 {
16 glMatrixMode(GL_MODELVIEW); //切换到模型视图矩阵
17 glLoadIdentity();
18 glRotatef(angle,1.0f,0.0f,0.0f);
19 glRotatef(angle, 0.0f, 1.0f, 0.0f);
20 glTranslatef(translate_x,0.0f,0.0f);
21 glScalef (zoom, zoom, zoom);
22 glutWireCube(1.5); //画立方体
23 }
24 glPopMatrix();
25 glFlush();
26 }
27
28 void reshape(int w,int h)
29 {
30 glViewport (0, 0, (GLsizei) w, (GLsizei) h); //调整视口位置和大小
31 glMatrixMode (GL_PROJECTION);//切换到投影矩阵
32 glLoadIdentity();//加载单位阵至投影矩阵
33 if (w <= h){
34 glOrtho(-3.0f, 3.0f, -3.0f/(w/h), 3.0f/(w/h), -3.0f, 3.0f);
35 }
36 else{
37 glOrtho(-3.0f*w/h, 3.0f*w/h, -3.0f, 3.0f, -3.0f, 3.0f);
38 }
39
40 glMatrixMode (GL_MODELVIEW);
41 glLoadIdentity();
42 }
43
44 void OnMouse(int button, int state, int x, int y)
45 {
46 //鼠标左键
47 if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
48 {
49 angle += 10.0f;
50 glutPostRedisplay();
51 }
52 //鼠标右键
53 else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
54 {
55 translate_x+=0.1f;
56 glutPostRedisplay();
57 }
58 //鼠标滚轮
59 else if (state == GLUT_UP && button == GLUT_WHEEL_DOWN)
60 {
61 if(zoom>0)
62 zoom-=0.1f;
63 glutPostRedisplay();
64 }
65 else if(state == GLUT_UP && button == GLUT_WHEEL_UP)
66 {
67 zoom+=0.1f;
68 glutPostRedisplay();
69 }
70 }
71
72
73 int main(int argc, char** argv)
74 {
75 glutInit(&argc, argv);
76 glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
77 glutInitWindowPosition(100,100);
78 glutInitWindowSize(500,500);
79 glutCreateWindow("cube");
80
81 glutDisplayFunc(myDisplay);
82 glutReshapeFunc(reshape);
83 glutMouseFunc( OnMouse );
84 glutMainLoop();
85 return 0;
86 }
采用了OpenGL的一些库函数实现，投影还是采用平行投影，表示对透视投影函数gluPerspective以及视点变化函数gluLookAt不是很清楚。
（三）
1 #include <windows.h>
2 #include<gl/glut.h>
3 #include <math.h>
4 #include<stdio.h>
5
6 GLfloat angle=0.0f;
7 GLfloat translate_x=0.0f;
8 GLfloat zoom=1.0f;
9
10 void myDisplay()
11 {
12 glClear (GL_COLOR_BUFFER_BIT);
13 glColor3f (1.0f, 1.0f, 1.0f);
14 glPushMatrix();
15
16 glMatrixMode(GL_MODELVIEW); //切换到模型视图矩阵
17 glLoadIdentity();
18 gluLookAt (0.0f, 0.0f, 5.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f); //设置相机参数
19 glRotatef(angle, 0.0f, 1.0f, 0.0f);
20 glTranslatef(translate_x,0.0f,0.0f);
21 glScalef (zoom, zoom, zoom);
22 glutWireCube(0.5); //画立方体
23
24 glPopMatrix();
25 glFlush();
26 }
27
28 void reshape(int w,int h)
29 {
30 glViewport (0, 0, (GLsizei) w, (GLsizei) h); //调整视口位置和大小
31 glMatrixMode (GL_PROJECTION);//切换到投影矩阵
32 glLoadIdentity();//加载单位阵至投影矩阵
33 gluPerspective(30,w/h,5,20);
34 glMatrixMode (GL_MODELVIEW);
35 glLoadIdentity();
36 }
37
38 void OnMouse(int button, int state, int x, int y)
39 {
40 //鼠标左键
41 if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
42 {
43 angle += 10.0f;
44 glutPostRedisplay();
45 }
46 //鼠标右键
47 else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
48 {
49 //xMov -= 0.1;
50 translate_x+=0.1f;
51 glutPostRedisplay();
52 }
53 //鼠标滚轮
54 else if (state == GLUT_UP && button == GLUT_WHEEL_DOWN)
55 {
56 if(zoom>0)
57 zoom-=0.1f;
58 glutPostRedisplay();
59 }
60 else if(state == GLUT_UP && button == GLUT_WHEEL_UP)
61 {
62 zoom+=0.1f;
63 glutPostRedisplay();
64 }
65 }
66
67
68 int main(int argc, char** argv)
69 {
70 glutInit(&argc, argv);
71 glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
72 glutInitWindowPosition(100,100);
73 glutInitWindowSize(500,500);
74 glutCreateWindow("cube");
75
76 glutDisplayFunc(myDisplay);
77 glutReshapeFunc(reshape);
78 glutMouseFunc( OnMouse );
79 glutMainLoop();
80 return 0;
81 }
用的是透视投影。我的理解是gluPerspective()和gluLookAt()要配合使用，二者中的相机位置要一致。
时间： 2024-10-13 02:56:56