下面就是glext为我们做的事：
(1), 根据显卡厂商对某个extension的具体说明来定义一些宏.
#define GL_ARRAY_BUFFER_ARB 0x8892 //具体的地址是在各个specification中定义的.
#define GL_STATIC_DRAW_ARB 0x88E4
(2), 声明一些函数指针的类型.
typedef void (APIENTRY * PFNGLBINDBUFFERARBPROC) (GLenum target, GLuint buffer);
typedef void (APIENTRY * PFNGLDELETEBUFFERSARBPROC) (GLsizei n, const GLuint *buffers);
typedef void (APIENTRY * PFNGLGENBUFFERSARBPROC) (GLsizei n, GLuint *buffers);
typedef void (APIENTRY * PFNGLBUFFERDATAARBPROC) (GLenum target, int size, const GLvoid *data, GLenum usage);
然后在我自己的实现中就需要做以下的事:
(3). 声明定义一些函数指针:
PFNGLGENBUFFERSARBPROC glGenBuffersARB = NULL;
PFNGLBINDBUFFERARBPROC glBindBufferARB = NULL;
PFNGLBUFFERDATAARBPROC glBufferDataARB = NULL;
PFNGLDELETEBUFFERSARBPROC glDeleteBuffersARB = NULL;
(4). 利用wglGetProcAddress函数取得各个函数的地址指针.
glBindBufferARB = (PFNGLBINDBUFFERARBPROC)wglGetProcAddress("glBindBufferARB");
glGenBuffersARB = (PFNGLGENBUFFERSARBPROC)wglGetProcAddress("glGenBuffersARB");
glBufferDataARB = (PFNGLBUFFERDATAARBPROC)wglGetProcAddress("glBufferDataARB");
而其实在glATI.h, wglATI.h, ATIExtensions.h, and ATIExtensions.c中也是这么做的.
那些glew, glee就将上面4步都给我们做了.
所以当使用extensions时候，
要么是下载glext回来，自己提供源代码实现(3, 4)两步.
要么是直接用glew or glee.
转载于:https://www.cnblogs.com/madfrog/archive/2010/06/25/1765243.html
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