GL_EXT_framebuffer_multisample
http://www.opengl.org/registry/specs/EXT/framebuffer_multisample.txt
GL_EXT_framebuffer_multisample
GL_RENDERBUFFER_SAMPLES_EXT 0x8CAB
GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT 0x8D56
GL_MAX_SAMPLES_EXT 0x8D57
void glRenderbufferStorageMultisampleEXT (GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height)
GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT 0x8D56
GL_MAX_SAMPLES_EXT 0x8D57