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authorNiklas Haas <[email protected]>2018-12-16 05:40:14 +0100
committerIlia Mirkin <[email protected]>2019-01-27 03:00:03 -0500
commitd9bd3b1cb874c44e4250c28605031ddf1c520cd1 (patch)
treec92eb84e37d30fe4dad577267be8e74ba712abcd /src/compiler/glsl/ir_variable_refcount.cpp
parent86e5f76d3d5a5608861813c051af2af4c075e814 (diff)
glsl: fix block member alignment validation for vec3
Section 7.6.2.2 (Standard Uniform Block Layout) of the GL spec says: The base offset of the first member of a structure is taken from the aligned offset of the structure itself. The base offset of all other structure members is derived by taking the offset of the last basic machine unit consumed by the previous member and adding one. The current code does not reflect this last sentence - it effectively instead aligns up the next offset up to the alignment of the previous member. This causes an issue in exactly one case: layout(std140) uniform block { layout(offset=0) vec3 var1; layout(offset=12) float var2; }; As per section 7.6.2.1 (Uniform Buffer Object Storage) and elsewhere, a vec3 consumes 3 floats, i.e. 12 basic machine units. Therefore, `var1` in the example above consumes units 0-11, with 12 being the first available offset afterwards. However, before this commit, mesa incorrectly assumes `var2` must start at offset=16 when using explicit offsets, which results in a compile-time error. Without explicit offsets, the shaders actually work fine, indicating that mesa is already correctly aligning these fields internally. (Just not in the code that handles explicit buffer offset parsing) This patch should fix piglit tests: ssbo-explicit-offset-vec3.vert ubo-explicit-offset-vec3.vert Signed-off-by: Niklas Haas <[email protected]> Reviewed-by: Ilia Mirkin <[email protected]>
Diffstat (limited to 'src/compiler/glsl/ir_variable_refcount.cpp')
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