On Thursday, October 19, 2017 9:02:20 PM PST Tomasz Figa wrote: > Hi Ian, Kenneth, > > On Wed, Sep 27, 2017 at 2:57 AM, Tomasz Figa <tf...@chromium.org> wrote: > > Commit 259fc505454ea6a67aeacf6cdebf1398d9947759 added linker error for > > mismatching uniform precision, as required by GLES 3.0 specification and > > conformance test-suite. > > > > Several Android applications, including Forge of Empires, have shaders > > which violate this rule, on uniforms that are declared but not used > > further in shader code. The problem affects a big number of Android > > games, including ones built on top of one of the common 2D graphics > > engines and other GLES implementations accept this, which poses a serious > > application compatibility issue. > > > > Starting from GLSL ES 3.0, declarations with conflicting precision > > qualifiers are explicitly prohibited. However GLSL ES 1.00 does not > > clearly specify the behavior, except that > > > > "Uniforms are defined to behave as if they are using the same storage in > > the vertex and fragment processors and may be implemented this way. > > If uniforms are used in both the vertex and fragment shaders, developers > > should be warned if the precisions are different. Conversion of > > precision should never be implicit." > > > > The word "used" is not clear in this context and might refer to > > 1) declared (same as GLES 3.x) > > 2) referred after post-processing, or > > 3) linked after all optimizations are done. > > > > Looking at existing applications, 2) or 3) seems to be widely adopted. > > To avoid compatibility issues, turn the error into a warning if GLSL ES > > version is lower than 3.0 and the data is dead in at least one of the > > shaders. > > > > v3: > > - Add a comment explaining the behavior. > > - Fix bad copy/paste in commit message (s/varyings/uniforms). > > Would you be able to take a look? > > Ian, I believe your previous NAK was due to the confusing erroneous > copy/paste from the freedesktop bug I made in commit message. Looking > at last comment from Kenneth there, we were going to go with my patch, > but things remained quiet after that. > > Thanks, > Tomasz
Sorry, this completely fell off my radar. I've gone ahead and pushed your patch. Dylan also sent out Piglit tests for this case today, which I've reviewed. --Ken
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