#177 GL_ARB_draw_instanced initialization is incorrect

[Anonymous]

Regarding glew 1.7.0 (and maybe earlier versions??):

The code that does the GetProcAddress lookup for glDrawArraysInstancedARB and glDrawElementsInstancedARB is misplaced in the _glewInit_GL_ARB_instanced_arrays() function.

So if GL_ARB_instanced_arrays is not supported by the GL, the glDrawArrays/ElementsARB function pointers are never initialized and
we crash when trying to call them.

The attached patch fixes the glew.c file which we have in piglit. You can easily adapt it for your glew tree. Is there a generator script for this file?

[Nobody/Anonymous]

patch, as taken from the piglit project.

[Nigel Stewart]

Indeed. Seems off that these would be grouped into ARB_instanced_arrays rather than ARB_draw_instanced.

[Nigel Stewart]

http://www.opengl.org/registry/specs/ARB/instanced_arrays.txt
The instanced_arrays spec includes the following:

If ARB_draw_instanced is not supported, all references to gl_InstanceIDARB
should be removed from section 2.8.  This extension will introduce
the following additional New Procedures and Functions:

    void DrawArraysInstancedARB(enum mode, int first, sizei count,
            sizei primcount);
    void DrawElementsInstancedARB(enum mode, sizei count, enum type,
            const void *indices, sizei primcount);

---

So GLEW needs to initialize these two functions pointers iff GL_ARB_instanced_arrays or GL_ARB_draw_instanced is available.