Hi All

After several days of debugging

I guess it's unroll problem (correct me if not). I use old ATI card intentionally as "minimal" because users can have any. So should I avoid unroll anywhere just because "there are some cards where it won't work"? What are better solutions for this?

Thank you

You can try running the code below just after the suspecious OpenGL call was made for visualizing the error code.

void CheckGLError()
{
	GLenum code = glGetError();
	if (code != GL_NO_ERROR)
	{
		fprintf(stderr, "OpenGL error = %d\n", code );
		assert(false);
	}
}

This could help you isolate the source of the crash.

Are there any errors that occur but currently aren't detected in the lead up to thecrash in glDrawElements, such as during shader linking?

Radeon HD 2000-4000: OpenGL propietary drivers are no longer updated. They're known for being a bit buggy now. Pre-Radeon HD 2000 (i.e. ATI Radeon X1000 series): These cards are so bad it drove us crazy back in the day. Unrolling your loop 8 times could be hitting the limit of 256 instruction slots these cards had.

ATI Radeon HD 2600 XT 256 MB
OpenGL Version: 2.1 ATI-7.32.12

Wait, this is a Mac on OS X?

The OS X OpenGL drivers are generally bad. Bugs like these are common. Does the problem go away if MAX_TEXTURES has other values (try 1, 2, 4...)

What version of macOS are you using? Updates tend to contain graphics driver updates (including bug fixes).