freeglut+glew一个小例子

1.GLEW介绍

GLEW是OpenGL常用的扩展库，可以在 http://glew.sourceforge.net/ 进行下载

2.实现

 1 #include <stdio.h>
 2
 3 #include <GL/glew.h>
 4 #include <GL/freeglut.h>
 5
 6 struct Vector3f
 7 {
 8     float x;
 9     float y;
10     float z;
11
12     Vector3f()
13     {
14     }
15
16     Vector3f(float _x, float _y, float _z)
17     {
18         x = _x;
19         y = _y;
20         z = _z;
21     }
22 };
23
24 GLuint VBO;
25
26 static void RenderSceneCB()
27 {
28     glClear(GL_COLOR_BUFFER_BIT);
29
30     glEnableVertexAttribArray(0);
31     glBindBuffer(GL_ARRAY_BUFFER, VBO);
32     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
33
34     glDrawArrays(GL_POINTS, 0, 1);
35
36     glDisableVertexAttribArray(0);
37
38     glutSwapBuffers();
39 }
40
41
42 static void InitializeGlutCallbacks()
43 {
44     glutDisplayFunc(RenderSceneCB);
45 }
46
47 static void CreateVertexBuffer()
48 {
49     Vector3f Vertices[1];
50     Vertices[0] = Vector3f(0.0f, 0.0f, 0.0f);
51
52     glGenBuffers(1, &VBO);
53     glBindBuffer(GL_ARRAY_BUFFER, VBO);
54     glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);
55 }
56
57
58 int main(int argc, char** argv)
59 {
60     glutInit(&argc, argv);
61     glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA);
62     glutInitWindowSize(1024, 768);
63     glutInitWindowPosition(100, 100);
64     glutCreateWindow("Tutorial 02");
65
66     InitializeGlutCallbacks();
67
68     // Must be done after glut is initialized!
69     GLenum res = glewInit();
70     if (res != GLEW_OK) {
71         fprintf(stderr, "Error: ‘%s‘\n", glewGetErrorString(res));
72         return 1;
73     }
74
75     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
76
77     CreateVertexBuffer();
78
79     glutMainLoop();
80
81     return 0;
82 }

Vector3f

首选定义一个自己的3D指标结构，方便信息表示

GLuint VBO;

用于存储定点缓存数据

glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);

设置缓存块，绑定缓存块，填充缓存块

glEnableVertexAttribArray(0);
glDisableVertexAttribArray(0);

在渲染前需要设置开启渲染管道属性，在渲染结束后需要关闭

glBindBuffer(GL_ARRAY_BUFFER, VBO);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);

glDrawArrays(GL_POINTS, 0, 1);//p1:绘制类型，p2:绘制Vertex起始位置，p3:绘制Vertex数目

在渲染前需要预先绑定已有数据，说明数据信息，绘制