Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 8d4c7092266659c6cf81d92ba23176feb8852178
https://github.com/WebKit/WebKit/commit/8d4c7092266659c6cf81d92ba23176feb8852178
Author: Kimmo Kinnunen <[email protected]>
Date: 2026-06-30 (Tue, 30 Jun 2026)
Changed paths:
M Source/ThirdParty/ANGLE/ANGLE.xcodeproj/project.pbxproj
Log Message:
-----------
ANGLE: Metal: Inconsistent implementation of various DrawElements variations
https://bugs.webkit.org/show_bug.cgi?id=312470
rdar://174919762
Reviewed by Dan Glastonbury.
The implementation of DrawElements would be inconsistent:
The implementation has multiple stages of possible intermediate buffers.
At various stages, offsets and counts were mixed between incorrect
stages.
Historically the confusions were partly due to the logic loading
the primitive ranges sometimes from generate intermediary buffers,
sometimes from the original client-provided buffer. This was partly
fixed to load only from client-provided buffers and client arrays
in "WebGL: consecutive UNSIGNED_BYTE drawElements() draw in wrong
location", but this caused a regression by other part of the code
using counts from incorrect stages.
The implementation strategy would not working for non-strip topologies,
such as GL_TRIANGLES, in primitive restart cases when provoking vertex
rewrite was needed. The provoking vertex rewrite operates per primitive.
For strip topologies, this works as each vertex index also defines a
primitive. For non-strip topologies, this is not possible as the
provoking vertex generation shader cannot know where the primitive
starts. Example: GL_TRIANGLES of {0, ff, 1, 2, 3, 4} would be dispatched
as primitives starting at 0 and 2, but the proper dispatch list
would contain just primitive at 1.
Furthermore, the logic to determine drawn index ranges was based on
scanning for primitive restart ranges, and then converting those
to draw index ranges. This algorithm was brittle and contained
quite many confusions.
Fix by:
- Resolve the draw index ranges by resolving the draw index ranges
instead of restart ranges. These index ranges are then intersected
with the client provided offset and count, which define the first
index, last index range pair.
- Consistently resolve the draw index ranges ƒrom the client buffers.
- Keep all intermediate buffers consistent with the first index, count:
the intermediate buffers always have the similar unused prefix
than the original client-provided index buffer.
- Keep all the intermediate buffers offsets separated from the
client-provided offset (first index). The intermediate buffers are
allocated from the buffer pool, so they're not separate buffers but
buffer, offset pairs. Keep these buffer, offset pairs separate from
the client first index
- For non-strip topology draws, provide the draw ranges already to the
provoking vertex shader helper. The provoking vertex shader is
only run for the real draw indices instead of the full draw.
This allows the shader to function correctly.
* Source/ThirdParty/ANGLE/ANGLE.xcodeproj/project.pbxproj:
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/BufferMtl.h:
(rx::DrawIndexRange::DrawIndexRange):
(rx::BufferMtl::DrawIndexRangeCache::DrawIndexRangeCache):
(rx::IndexRange::IndexRange): Deleted.
(rx::BufferMtl::RestartRangeCache::RestartRangeCache): Deleted.
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/BufferMtl.mm:
(rx::BufferMtl::markConversionBuffersDirty):
(rx::BufferMtl::clearConversionBuffers):
(rx::CalculateDrawIndexRanges):
(rx::BufferMtl::getDrawIndexRanges):
(rx::BufferMtl::GetDrawIndexRangesFromClientData):
(rx::IndexConversionBufferMtl::getRangeForConvertedBuffer): Deleted.
(rx::CalculateRestartRanges): Deleted.
(rx::BufferMtl::getRestartIndices): Deleted.
(rx::BufferMtl::GetRestartIndicesFromClientData): Deleted.
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/ContextMtl.h:
(rx::ContextMtl::getProvokingVertexHelper):
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/ContextMtl.mm:
(rx::ContextMtl::drawElementsImpl):
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/ProvokingVertexHelper.h:
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/ProvokingVertexHelper.mm:
(rx::ProvokingVertexHelper::preconditionIndexBuffer):
(rx::ProvokingVertexHelper::generateIndexBuffer):
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/VertexArrayMtl.h:
* Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/VertexArrayMtl.mm:
(rx::AppendDrawCommands):
(rx::AppendDrawCommandRanges):
(rx::VertexArrayMtl::resolveDrawElementsDraw):
(rx::VertexArrayMtl::getIndexBuffer): Deleted.
(rx::VertexArrayMtl::getDrawIndices): Deleted.
*
Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/VertexArrayMtl_unittest.mm:
Added.
* Source/ThirdParty/ANGLE/src/tests/gl_tests/DrawElementsTest.cpp:
(angle::convertIndexBufferContents):
Originally-landed-as: 305413.713@safari-7624-branch (23eba5e02916).
rdar://180437073
Canonical link: https://commits.webkit.org/316130@main
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