Fix packSnorm2x16.

Casting -32767.0f to uint16_t on Android resulted in 0. According to C99 6.3.1.4 footnote 50 this kind of cast behavior is unspecified BUG=angleproject:913 TEST=build/android/test_runner.py gtest -s angle_unittests --release Change-Id: I136386fe0aa618c17f07f99d8e1ca72fa407d36a Reviewed-on: https://chromium-review.googlesource.com/323230 Tryjob-Request: Yuly Novikov <ynovikov@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Tryjob-Request: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Tested-by: Yuly Novikov <ynovikov@chromium.org>

Fix packSnorm2x16.
451ed25a · Yuly Novikov · a8e3494e · 451ed25a
Commit 451ed25a authored Jan 21, 2016 by Yuly Novikov
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mathutil.h src/common/mathutil.h +4 -3

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--- a/src/common/mathutil.h
+++ b/src/common/mathutil.h
@@ -585,9 +585,10 @@ struct IndexRange
 // packSnorm2x16 : round(clamp(c, -1, +1) * 32767.0)
 inline uint32_t packSnorm2x16(float f1, float f2)
 {
-    uint16_t leastSignificantBits = static_cast<uint16_t>(roundf(clamp(f1, -1.0f, 1.0f) * 32767.0f));
+    int16_t leastSignificantBits = static_cast<int16_t>(roundf(clamp(f1, -1.0f, 1.0f) * 32767.0f));
-    uint16_t mostSignificantBits = static_cast<uint16_t>(roundf(clamp(f2, -1.0f, 1.0f) * 32767.0f));
+    int16_t mostSignificantBits = static_cast<int16_t>(roundf(clamp(f2, -1.0f, 1.0f) * 32767.0f));
-    return static_cast<uint32_t>(mostSignificantBits) << 16 | static_cast<uint32_t>(leastSignificantBits);
+    return static_cast<uint32_t>(mostSignificantBits) << 16 |
+           (static_cast<uint32_t>(leastSignificantBits) & 0xFFFF);
 }
 // First, unpacks a single 32-bit unsigned integer u into a pair of 16-bit unsigned integers. Then, each