Hey. I’m finally thinking of making the move to uniform buffers, but I’m a bit confused by the spec, specifically the limitations imposed by GL_MAX_UNIFORM_BLOCK_SIZE.
According to the wiki this limitation applies to the uniform buffer size.
[quote]There is also a limitation on the available storage per uniform buffer. This is queried through GL_MAX_UNIFORM_BLOCK_SIZE. This is in basic machine units (ie: bytes).
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That means that the biggest uniform buffer I can ever create is 16kbs, which would severely limit my ability to pack the uniforms for a large number of draw calls in the same buffer. Having model+view+projection matrices alone limits me to 85 draw calls without any other uniforms limits me to 85 draw calls per buffer. This is really annoying.
The spec however says this about GL_MAX_UNIFORM_BLOCK_SIZE:
[quote]Max size in basic machine units of a uniform block
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That would mean that I could create a uniform buffer as big as I want as long as no uniform block is bigger than 16kbs, which I won’t ever get close to. And indeed, the Nvidia driver throws no error when I create an almost 2GB big uniform buffer, just kindly informing me that it was placed in video memory.
The wiki must be wrong here, right? I just want to rule out that this is an Nvidia quirk.