Fix bug in calcSafeRadians. (#1138)

3 files changed, 59 insertions, 6 deletions

diff --git a/prelude/slang-cpp-scalar-intrinsics.h b/prelude/slang-cpp-scalar-intrinsics.h
index 081b31265..70f5ec01a 100644
--- a/prelude/slang-cpp-scalar-intrinsics.h
+++ b/prelude/slang-cpp-scalar-intrinsics.h
@@ -30,9 +30,12 @@ union Union64
 // Helpers
 SLANG_FORCE_INLINE float F32_calcSafeRadians(float radians)
 {
-	float a = radians * (1.0f /  float(SLANG_PRELUDE_PI));
-	a = (a < 0.0f) ? (::ceilf(a) - a) : (a - ::floorf(a));
-	return (a * float(SLANG_PRELUDE_PI));
+    // Put 0 to 2pi cycles to cycle around 0 to 1 
+	float a = radians * (1.0f /  float(SLANG_PRELUDE_PI * 2));
+    // Get truncated fraction, as value in  0 - 1 range
+    a = a - ::floorf(a);
+    // Convert back to 0 - 2pi range
+	return (a * float(SLANG_PRELUDE_PI * 2));
 }
 
 // Unary 
@@ -79,9 +82,12 @@ SLANG_FORCE_INLINE int32_t F32_asint(float f) { Union32 u; u.f = f; return u.i;
 
 SLANG_FORCE_INLINE double F64_calcSafeRadians(double radians)
 {
-    double a = radians * (1.0 / SLANG_PRELUDE_PI);
-    a = (a < 0.0) ? (::ceil(a) - a) : (a - ::floor(a));
-    return (a * SLANG_PRELUDE_PI);
+    // Put 0 to 2pi cycles to cycle around 0 to 1 
+	double a = radians * (1.0f /  (SLANG_PRELUDE_PI * 2));
+    // Get truncated fraction, as value in  0 - 1 range
+    a = a - ::floor(a);
+    // Convert back to 0 - 2pi range
+	return (a * (SLANG_PRELUDE_PI * 2));
 }
 
 // Unary 
diff --git a/tests/compute/transcendental.slang b/tests/compute/transcendental.slang
new file mode 100644
index 000000000..aa40da752
--- /dev/null
+++ b/tests/compute/transcendental.slang
@@ -0,0 +1,31 @@
+//TEST(compute):COMPARE_COMPUTE:-cpu
+//TEST(compute):COMPARE_COMPUTE:
+//TEST(compute,vulcan):COMPARE_COMPUTE:-vk
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<int> outputBuffer : register(u0);
+
+int quantize(double value)
+{
+    return int(value * 256);
+}
+
+int quantize(float value)
+{
+    return int(value * 256);
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    float values[] = { -9, 9, -3, 3 };
+
+	int tid = int(dispatchThreadID.x);
+    float value = values[tid];
+    
+    outputBuffer[tid * 4] = quantize(sin(value));
+    outputBuffer[tid * 4 + 1] = quantize(cos(value));
+    
+    outputBuffer[tid * 4 + 2] = quantize(sin(double(value)));
+    outputBuffer[tid * 4 + 3] = quantize(cos(double(value)));
+}
\ No newline at end of file
diff --git a/tests/compute/transcendental.slang.expected.txt b/tests/compute/transcendental.slang.expected.txt
new file mode 100644
index 000000000..4a525cc7c
--- /dev/null
+++ b/tests/compute/transcendental.slang.expected.txt
@@ -0,0 +1,16 @@
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+FFFFFF17
+FFFFFF97
+FFFFFF17
+69
+FFFFFF17
+69
+FFFFFF17
+FFFFFFDC
+FFFFFF03
+FFFFFFDC
+FFFFFF03
+24
+FFFFFF03
+24
+FFFFFF03