Assert when glDrawElements cannot draw anything because of missing vertex bounds#26525
Assert when glDrawElements cannot draw anything because of missing vertex bounds#26525paradust7 wants to merge 1 commit intoemscripten-core:mainfrom
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| if (!cb.clientside || !cb.enabled) continue; | ||
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| #if ASSERTIONS | ||
| assert(count || !GLctx.currentElementArrayBufferBinding, 'must use array buffers when using element buffer'); |
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Does this assert belong here inside this for loop? Could it not go outside the loop?
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Should this be !count || !GLctx.currentElementArrayBufferBinding ? (i.e. I'm not sure what the count || part is doing here.
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It is written as intended, but there may be an edge case I didn't consider.
preDrawHandleClientVertexAttribBindings is called in two places. It is called by glDrawArrays, where the vertex count is always passed by the user. And in glDrawElements, where the vertex count is computed if it can be, or otherwise passed as 0.
The error case is only for glDrawElements, when the vertex count cannot be computed, so that the count is passed as 0, even though the real count is non-zero.
I added the "count ||" to make sure the assert doesn't fire for glDrawArrays. But it could still fire if glDrawArrays is called with a count of 0.
I'll get a fix for this ready.
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I'm afraid I don't really know this code well enough to know for sure if this correct. @juj WDYT? |
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Even with FULL_ES2, glDrawElements cannot handle the case where the indices are in a buffer but the vertices are client-side. Nothing will be drawn in this case. Add an assertion to make this situation visible when debugging.
Fixes #26460