Testing on an Android Nexus 4 (newest hw model I think?) with an Adreno 320 GPU and Android 4.4.2, the GLES2 context does report support for GL_OES_standard_derivatives, but at the same time, visiting e.g. this page http://renderingpipeline.com/webgl-extension-viewer/ to view the available WebGL extensions, the extension OES_standard_derivatives is not available. Looks like the WebGL extension OES_standard_derivatives maps 1:1 to GL_OES_standard_derivatives, so it should be supported when the native GLES2 extension is supported as well?
So it's broken on the Adreno 320, as reported in bug 875696 -- unfortunately that bug has zero information in it as to what's broken.
In cases like this, you can easily try out if it works for you by setting this preference: gfx.work-around-driver-bugs = false
My N4 on 4.4 seems to pass the standard_derivatives test when I ignore driver workarounds. We can re-enable this for android 4.4+, if we can figure out how to do this.
Look around widget/android/GfxInfo.cpp for examples of how to query the Android version.
I've encountered this bug as well on my device (details below), and consulting http://webglstats.com/ , Google Chrome Mobile supports OES_standard_derivatives to 99.9%, whereas Mobile Firefox supports it with 82.6%. Model Number: Nexus 4 Android: 5.0 Kernel version: 3.4.0-perf-g60eefcd email@example.com #1 Fri Oct 10 18:28:38 UTC 2014 Build Number: LRX21T Firefox: 34.0 & Beta 34.0 When toggling gfx.work-around-driver-bugs to false, OES_standard_derivatives shows up. However the quality is compromised (lots of artifacts). But Chrome also shows artifacts. These artifacts are not found on iOS or Desktop machines (see http://codeflow.org/issues/standard-derivatives-nexus4.png ).
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