Fix division by zero

Fixed format threshold calculation caused division by zero
whenever less than four channels were used by the format.
This change uses threshold zero for the empty channels.

VK-GL-CTS Issue: 3332

Affects:

dEQP-GLES31.functional.draw_buffers_indexed.random.max_implementation_draw_buffers.*

Components: OpenGL ES
Change-Id: Ib6c8ee6ee0fa82d1f0514b639938c61ed7762381

diff --git a/modules/gles31/functional/es31fDrawBuffersIndexedTests.cpp b/modules/gles31/functional/es31fDrawBuffersIndexedTests.cpp
index d190461..a934b5d 100644 (file)
--- a/modules/gles31/functional/es31fDrawBuffersIndexedTests.cpp
+++ b/modules/gles31/functional/es31fDrawBuffersIndexedTests.cpp
@@ -446,7 +446,19 @@ Vec4 getFixedPointFormatThreshold (const tcu::TextureFormat& sourceFormat, const
        const tcu::IVec4        srcBits         = tcu::getTextureFormatBitDepth(sourceFormat);
        const tcu::IVec4        readBits        = tcu::getTextureFormatBitDepth(readPixelsFormat);
 
-       return Vec4(3.0f) / ((tcu::Vector<deUint64, 4>(1) << (tcu::min(srcBits, readBits).cast<deUint64>())) - tcu::Vector<deUint64, 4>(1)).cast<float>();
+       Vec4                            threshold       = Vec4(0.0f);
+
+       for (int i = 0; i < 4; i++)
+       {
+               const int bits = de::min(srcBits[i], readBits[i]);
+
+               if (bits > 0)
+               {
+                       threshold[i] = 3.0f / static_cast<float>(((1ul << bits) - 1ul));
+               }
+       }
+
+       return threshold;
 }
 
 UVec4 getFloatULPThreshold (const tcu::TextureFormat& sourceFormat, const tcu::TextureFormat& readPixelsFormat)