Fix unpackUnorm4x8 and unpackSnorm4x8 (#4033)

Fixes #4031

Each component of unpackU/Snorm4x8 had to be masked for 8bits.

1 files changed, 54 insertions, 0 deletions

diff --git a/tests/bugs/gh-4031.slang b/tests/bugs/gh-4031.slang
new file mode 100644
index 000000000..015eeefc6
--- /dev/null
+++ b/tests/bugs/gh-4031.slang
@@ -0,0 +1,54 @@
+//TEST(compute):COMPARE_COMPUTE_EX(filecheck-buffer=BUF):-dx12 -compute -entry computeMain -allow-glsl -profile cs_6_6 -use-dxil -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=BUF):-vk -compute -entry computeMain -allow-glsl -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=BUF):-vk -compute -entry computeMain -allow-glsl -output-using-type -emit-spirv-directly
+
+//TEST_INPUT: ubuffer(data=[0], stride=4):out,name outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+bool Test_unpackUnorm4x8()
+{
+    vector<float,4> val;
+    val[0] = 1.f / 1.f;
+    val[1] = 1.f / 2.f;
+    val[2] = 1.f / 4.f;
+    val[3] = 1.f / 8.f;
+
+    const uint32_t packed = packUnorm4x8(val);
+    const vector<float,4> unpacked = unpackUnorm4x8(packed);
+
+    return true
+        && int(unpacked[0] * 1.f) == 1
+        && int(unpacked[1] * 2.f) == 1
+        && int(unpacked[2] * 4.f) == 1
+        && int(unpacked[3] * 8.f) == 1
+        ;
+}
+
+bool Test_unpackSnorm4x8()
+{
+    vector<float,4> val;
+    val[0] = 1.f / 1.f;
+    val[1] = 1.f / 2.f;
+    val[2] = 1.f / 4.f;
+    val[3] = 1.f / 8.f;
+
+    const uint32_t packed = packSnorm4x8(val);
+    const vector<float,4> unpacked = unpackSnorm4x8(packed);
+
+    return true
+        && int(unpacked[0] * 1.f) == 1
+        && int(unpacked[1] * 2.f) == 1
+        && int(unpacked[2] * 4.f) == 1
+        && int(unpacked[3] * 8.f) == 1
+        ;
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    //BUF:1
+    outputBuffer[0] = int(true
+        && Test_unpackUnorm4x8()
+        && Test_unpackSnorm4x8()
+        );
+}