Basic RNG

shader/_test-rng-xoroshiro128plus.slang

@@ -0,0 +1,18 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX:-cpu -compute -shaderobj -output-using-type
+
+import rng;
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0 0 0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<uint64_t> outputBuffer;
+
+[numthreads(1, 1, 1)]
+void computeMain(int3 dispatchThreadID : SV_DispatchThreadID)
+{
+    Xoroshiro128Plus rng = {1, 2};
+    for (int i = 0; i < 5; i++)
+    {
+        outputBuffer[i] = rng.next();
+    }
+}

shader/_test-rng-xoroshiro128plus.slang.expected.txt

@@ -0,0 +1,6 @@
+type: uint64_t
+3
+412333834243
+2360170716294286339
+9295852285959843169
+2797080929874688578

shader/hello-world.slang

@@ -2,10 +2,15 @@ StructuredBuffer<float> buffer0;
 StructuredBuffer<float> buffer1;
 RWStructuredBuffer<float> result;
 
+import rng;
+
 [shader("compute")]
 [numthreads(1,1,1)]
 void computeMain(uint3 threadId : SV_DispatchThreadID)
 {
-    uint index = threadId.x;
-    result[index] = buffer0[index] + buffer1[index];
-}
+    Xoroshiro128Plus generator = {1, 2};
+    for (var i = 0; i < 10; i++)
+    {
+        result[i] = generator.next();
+    }
+}

shader/rng.slang

@@ -0,0 +1,44 @@
+module rng;
+
+public interface IRngCore
+{
+    [mutating]
+    public uint64_t next();
+
+    [mutating]
+    public float next_float();
+}
+
+uint64_t rotl(uint64_t x, int k)
+{
+    return (x << k) | (x >> (64 - k));
+}
+
+float u64_to_float(uint64_t x)
+{
+    return 0;
+}
+
+public struct Xoroshiro128Plus : IRngCore
+{
+    internal uint64_t s0;
+    internal uint64_t s1;
+
+    [mutating]
+    public uint64_t next()
+    {
+        var result = s0 + s1;
+
+        s1 ^= s0;
+        s0 = rotl(s0, 24) ^ s1 ^ (s1 << 16);
+        s1 = rotl(s1, 37);
+
+        return result;
+    }
+
+    [mutating]
+    public float next_float()
+    {
+        return u64_to_float(next());
+    }
+}