Author :
Shahbaz Youssefi
Date :
2021-07-29 11:19:33
Hash :ebe943e2 Message :Vulkan: SPIR-V Gen: Fix gl_Clip/CullDistance
These built-ins can be redeclared in the shader. The translator took
these redeclarations (and gl_LastFragData) as UserDefined symbols.
There were a number of hacks such as in name generation and
CollectVariables, to special-case these redeclarations.
This change instead makes sure that these variables continue to be
considered built-ins with the appropriate qualifiers. A number of fixes
are made accordingly:
- Hacks are removed.
- In fragment shaders, ANGLEClipDistance was initialized with
gl_ClipDistance for further use by the shader. The code generation
however mistakenly produced `gl_ClipDistance[0] =
ANGLEClipDistance[0];`, which caused compilation failures by glslang,
but passed the tests accidentally because they expected link failures
(see next item).
- CollectVariables is fixed to correctly collect gl_Clip/CullDistance
in fragment shaders; previously they were collected as output
varyings, and therefore the aforementioned link error was not produced
in the tests after the compilation error was fixed.
Additional fixes:
- The transformation of gl_Clip/CullDistance was always ever done on one
of them due to misplaced breaks in the loop that detected their
presence.
- The transformation of gl_CullDistance was skipped when it was not
redeclared.
Validation is added to make sure these built-ins always have the correct
qualifier even when redeclared. SPIR-V gen support for these variables
have been fixed as well.
Bug: angleproject:4889
Change-Id: Ic8bf2c508357035cb937ef41a28ae22ffc533ebe
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3059921
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Shahbaz Youssefi