1GL_MESAX_texture_stack 2http://www.opengl.org/registry/specs/MESAX/texture_stack.txt 3GL_MESAX_texture_stack 4 GL_TEXTURE_1D_STACK_MESAX 0x8759 5 GL_TEXTURE_2D_STACK_MESAX 0x875A 6 GL_PROXY_TEXTURE_1D_STACK_MESAX 0x875B 7 GL_PROXY_TEXTURE_2D_STACK_MESAX 0x875C 8 GL_TEXTURE_1D_STACK_BINDING_MESAX 0x875D 9 GL_TEXTURE_2D_STACK_BINDING_MESAX 0x875E 10