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GL 4.4.12874 Texture array clear performance

Question asked by Taz1024 on Apr 25, 2014



I ran into an unexpected performance issue with clearing 2d texture arrays, so I tried some work-arounds. The huge differences in gpu time seem to indicate there's something wrong with the implementation of clears (clearbuffer, cleartexsubimage) for 2d arrays. Here are the results:


rgba16f, 64x64x192:

- glClearBufferfv(): 400us

- glClearTexSubImage: 400us

- Draw 192 slices: 136us

- Compute: 35us


depth24s8, 64x64x192:

- glClearBufferfi(): 334us

- glClearSubTexImage(): 334us

- Draw 192 slices: 27us

- Compute: no image store avail for depth-stencil =(


Also worth noting is that clearbuffer and clearsubteximage take about ~40us cpu setup time compared to compute setup of ~15us.