Relax EGL functional test thresholds

The current threshold of 0.02 was selected as suitable for 8-bit color depths.
However, for smaller bit depths such as RGB565 this threshold is too strict
and it has been relaxed to allow a larger error for low bit depth formats.

Affects:
dEQP-EGL.functional.render.*

Change-Id: I6d6e061be02bc8e63cb5d9662feb804bc839d567

diff --git a/modules/egl/teglRenderTests.cpp b/modules/egl/teglRenderTests.cpp
index be012e3..46b1780 100644 (file)
--- a/modules/egl/teglRenderTests.cpp
+++ b/modules/egl/teglRenderTests.cpp
@@ -356,6 +356,37 @@ tcu::TextureFormat getColorFormat (const tcu::PixelFormat& colorBits)
 #undef PACK_FMT
 }
 
+/*
+The getColorThreshold function is used to obtain a
+threshold usable for the fuzzyCompare function.
+
+For 8bit color depths a value of 0.02 should provide
+a good metric for rejecting images above this level.
+For other bit depths other thresholds should be selected.
+Ideally this function would take advantage of the
+getColorThreshold function provided by the PixelFormat class
+as this would also allow setting per channel thresholds.
+However using the PixelFormat provided function can result
+in too strict thresholds for 8bit bit depths (compared to
+the current default of 0.02) or too relaxed for lower bit
+depths if scaled proportionally to the 8bit default.
+*/
+
+float getColorThreshold (const tcu::PixelFormat& colorBits)
+{
+       if ((colorBits.redBits > 0 && colorBits.redBits < 8) ||
+               (colorBits.greenBits > 0 && colorBits.greenBits < 8) ||
+               (colorBits.blueBits > 0 && colorBits.blueBits < 8) ||
+               (colorBits.alphaBits > 0 && colorBits.alphaBits < 8))
+       {
+               return 0.05f;
+       }
+       else
+       {
+               return 0.02f;
+       }
+}
+
 tcu::TextureFormat getDepthFormat (const int depthBits)
 {
        switch (depthBits)
@@ -699,9 +730,9 @@ void SingleThreadRenderCase::executeForContexts (EGLDisplay display, EGLSurface
        const int                               numContexts     = (int)contexts.size();
        const int                               drawsPerCtx     = 2;
        const int                               numIters        = 2;
-       const float                             threshold       = 0.02f;
-
        const tcu::PixelFormat  pixelFmt        = getPixelFormat(egl, display, config.config);
+       const float                             threshold       = getColorThreshold(pixelFmt);
+
        const int                               depthBits       = eglu::getConfigAttribInt(egl, display, config.config, EGL_DEPTH_SIZE);
        const int                               stencilBits     = eglu::getConfigAttribInt(egl, display, config.config, EGL_STENCIL_SIZE);
        const int                               numSamples      = eglu::getConfigAttribInt(egl, display, config.config, EGL_SAMPLES);
@@ -903,9 +934,9 @@ void MultiThreadRenderCase::executeForContexts (EGLDisplay display, EGLSurface s
        const int                               packetsPerThread        = 2;
        const int                               numThreads                      = numContexts;
        const int                               numPackets                      = numThreads * packetsPerThread;
-       const float                             threshold                       = 0.02f;
-
        const tcu::PixelFormat  pixelFmt                        = getPixelFormat(egl, display, config.config);
+       const float                             threshold                       = getColorThreshold(pixelFmt);
+
        const int                               depthBits                       = eglu::getConfigAttribInt(egl, display, config.config, EGL_DEPTH_SIZE);
        const int                               stencilBits                     = eglu::getConfigAttribInt(egl, display, config.config, EGL_STENCIL_SIZE);
        const int                               numSamples                      = eglu::getConfigAttribInt(egl, display, config.config, EGL_SAMPLES);