Improve the support of the Fibonacci sequence

8 年前 · dba98485
--- a/Assets/ScriptableRenderLoop/HDRenderLoop/Sky/Resources/GGXConvolve.shader
+++ b/Assets/ScriptableRenderLoop/HDRenderLoop/Sky/Resources/GGXConvolve.shader
                                            PerceptualRoughnessToRoughness(perceptualRoughness),
                                            _MipMapCount,
                                            _InvOmegaP,
-                                            55, // Matches the size of the precomputed Fibonacci sequence
+                                            55, // Matches the size of the precomputed Fibonacci point set
                                            true);

                return val;
--- a/Assets/ScriptableRenderLoop/ShaderLibrary/Hammersley2D.hlsl
+++ b/Assets/ScriptableRenderLoop/ShaderLibrary/Hammersley2D.hlsl

 // Loads elements from one of the precomputed tables for sequence lengths of 16, 32, 64, 256.
 // Computes the values at runtime otherwise.
+// For sampling, the size of the point set is the same as the sequence length.
 float2 Hammersley2d(uint i, uint sequenceLength)
 {
    switch (sequenceLength)
--- a/Assets/ScriptableRenderLoop/ShaderLibrary/ImageBasedLighting.hlsl
+++ b/Assets/ScriptableRenderLoop/ShaderLibrary/ImageBasedLighting.hlsl
                    float roughness,
                    float mipmapcount,
                    float invOmegaP,
-                    uint sampleCount,
+                    uint sampleCount,      // Matches the size of the precomputed Fibonacci point set
                    bool prefilter = true) // static bool
 {
    float3 acc          = float3(0.0, 0.0, 0.0);
--- a/Assets/ScriptableRenderLoop/ShaderLibrary/Sampling.hlsl
+++ b/Assets/ScriptableRenderLoop/ShaderLibrary/Sampling.hlsl
 // Sample generator
 //-----------------------------------------------------------------------------

+#include "Fibonacci2D.hlsl"
 #include "Hammersley2D.hlsl"

 float Hash(uint s)

    return r;
 }
-
-static const float2 k_Fibonacci2dSeq55[] = {
-    float2(0.00000000, 0.00000000),
-    float2(0.61818182, 0.01818182),
-    float2(0.23636365, 0.03636364),
-    float2(0.85454547, 0.05454545),
-    float2(0.47272730, 0.07272727),
-    float2(0.09090900, 0.09090909),
-    float2(0.70909095, 0.10909091),
-    float2(0.32727289, 0.12727273),
-    float2(0.94545460, 0.14545454),
-    float2(0.56363630, 0.16363636),
-    float2(0.18181801, 0.18181819),
-    float2(0.80000019, 0.20000000),
-    float2(0.41818190, 0.21818182),
-    float2(0.03636360, 0.23636363),
-    float2(0.65454578, 0.25454545),
-    float2(0.27272701, 0.27272728),
-    float2(0.89090919, 0.29090908),
-    float2(0.50909138, 0.30909091),
-    float2(0.12727261, 0.32727271),
-    float2(0.74545479, 0.34545454),
-    float2(0.36363602, 0.36363637),
-    float2(0.98181820, 0.38181818),
-    float2(0.60000038, 0.40000001),
-    float2(0.21818161, 0.41818181),
-    float2(0.83636379, 0.43636364),
-    float2(0.45454597, 0.45454547),
-    float2(0.07272720, 0.47272727),
-    float2(0.69090843, 0.49090910),
-    float2(0.30909157, 0.50909090),
-    float2(0.92727280, 0.52727270),
-    float2(0.54545403, 0.54545456),
-    float2(0.16363716, 0.56363636),
-    float2(0.78181839, 0.58181816),
-    float2(0.39999962, 0.60000002),
-    float2(0.01818275, 0.61818182),
-    float2(0.63636398, 0.63636363),
-    float2(0.25454521, 0.65454543),
-    float2(0.87272835, 0.67272729),
-    float2(0.49090958, 0.69090909),
-    float2(0.10909081, 0.70909089),
-    float2(0.72727203, 0.72727275),
-    float2(0.34545517, 0.74545455),
-    float2(0.96363640, 0.76363635),
-    float2(0.58181763, 0.78181821),
-    float2(0.20000076, 0.80000001),
-    float2(0.81818199, 0.81818181),
-    float2(0.43636322, 0.83636361),
-    float2(0.05454636, 0.85454547),
-    float2(0.67272758, 0.87272727),
-    float2(0.29090881, 0.89090908),
-    float2(0.90909195, 0.90909094),
-    float2(0.52727318, 0.92727274),
-    float2(0.14545441, 0.94545454),
-    float2(0.76363754, 0.96363634),
-    float2(0.38181686, 0.98181820)
-};

 //-----------------------------------------------------------------------------
 // Sampling function
--- a/Assets/ScriptableRenderLoop/ShaderLibrary/Fibonacci2D.hlsl
+++ b/Assets/ScriptableRenderLoop/ShaderLibrary/Fibonacci2D.hlsl
+#ifndef UNITY_FIBONACCI_INCLUDED
+#define UNITY_FIBONACCI_INCLUDED
+
+// Computes a point using the Fibonacci sequence of length N.
+// Input: Fib[N - 1], Fib[N - 2], and the index 'i' of the point.
+// Ref: Integration of nonperiodic functions of two variables by Fibonacci lattice rules
+float2 Fibonacci2dSeq(float fibN1, float fibN2, int i)
+{
+    // 3 cycles on GCN if 'fibN1' and 'fibN2' are known at compile time.
+    return float2(i / fibN1, frac(i * (fibN2 / fibN1)));
+}
+
+static const int k_FibonacciSeq[] = {
+    0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377
+};
+
+static const float2 k_Fibonacci2dSeq21[] = {
+    float2(0.00000000, 0.00000000),
+    float2(0.04761905, 0.61904764),
+    float2(0.09523810, 0.23809528),
+    float2(0.14285715, 0.85714293),
+    float2(0.19047619, 0.47619057),
+    float2(0.23809524, 0.09523821),
+    float2(0.28571430, 0.71428585),
+    float2(0.33333334, 0.33333349),
+    float2(0.38095239, 0.95238113),
+    float2(0.42857143, 0.57142878),
+    float2(0.47619048, 0.19047642),
+    float2(0.52380955, 0.80952406),
+    float2(0.57142860, 0.42857170),
+    float2(0.61904764, 0.04761887),
+    float2(0.66666669, 0.66666698),
+    float2(0.71428573, 0.28571510),
+    float2(0.76190478, 0.90476227),
+    float2(0.80952382, 0.52380943),
+    float2(0.85714287, 0.14285755),
+    float2(0.90476191, 0.76190567),
+    float2(0.95238096, 0.38095284)
+};
+
+static const float2 k_Fibonacci2dSeq34[] = {
+    float2(0.00000000, 0.00000000),
+    float2(0.02941176, 0.61764705),
+    float2(0.05882353, 0.23529410),
+    float2(0.08823530, 0.85294116),
+    float2(0.11764706, 0.47058821),
+    float2(0.14705883, 0.08823538),
+    float2(0.17647059, 0.70588231),
+    float2(0.20588236, 0.32352924),
+    float2(0.23529412, 0.94117641),
+    float2(0.26470590, 0.55882359),
+    float2(0.29411766, 0.17647076),
+    float2(0.32352942, 0.79411745),
+    float2(0.35294119, 0.41176462),
+    float2(0.38235295, 0.02941132),
+    float2(0.41176471, 0.64705849),
+    float2(0.44117647, 0.26470566),
+    float2(0.47058824, 0.88235283),
+    float2(0.50000000, 0.50000000),
+    float2(0.52941179, 0.11764717),
+    float2(0.55882353, 0.73529434),
+    float2(0.58823532, 0.35294151),
+    float2(0.61764705, 0.97058773),
+    float2(0.64705884, 0.58823490),
+    float2(0.67647058, 0.20588207),
+    float2(0.70588237, 0.82352924),
+    float2(0.73529410, 0.44117641),
+    float2(0.76470590, 0.05882263),
+    float2(0.79411763, 0.67646980),
+    float2(0.82352942, 0.29411697),
+    float2(0.85294116, 0.91176414),
+    float2(0.88235295, 0.52941132),
+    float2(0.91176468, 0.14705849),
+    float2(0.94117647, 0.76470566),
+    float2(0.97058821, 0.38235283)
+};
+
+static const float2 k_Fibonacci2dSeq55[] = {
+    float2(0.00000000, 0.00000000),
+    float2(0.01818182, 0.61818182),
+    float2(0.03636364, 0.23636365),
+    float2(0.05454545, 0.85454547),
+    float2(0.07272727, 0.47272730),
+    float2(0.09090909, 0.09090900),
+    float2(0.10909091, 0.70909095),
+    float2(0.12727273, 0.32727289),
+    float2(0.14545454, 0.94545460),
+    float2(0.16363636, 0.56363630),
+    float2(0.18181819, 0.18181801),
+    float2(0.20000000, 0.80000019),
+    float2(0.21818182, 0.41818190),
+    float2(0.23636363, 0.03636360),
+    float2(0.25454545, 0.65454578),
+    float2(0.27272728, 0.27272701),
+    float2(0.29090908, 0.89090919),
+    float2(0.30909091, 0.50909138),
+    float2(0.32727271, 0.12727261),
+    float2(0.34545454, 0.74545479),
+    float2(0.36363637, 0.36363602),
+    float2(0.38181818, 0.98181820),
+    float2(0.40000001, 0.60000038),
+    float2(0.41818181, 0.21818161),
+    float2(0.43636364, 0.83636379),
+    float2(0.45454547, 0.45454597),
+    float2(0.47272727, 0.07272720),
+    float2(0.49090910, 0.69090843),
+    float2(0.50909090, 0.30909157),
+    float2(0.52727270, 0.92727280),
+    float2(0.54545456, 0.54545403),
+    float2(0.56363636, 0.16363716),
+    float2(0.58181816, 0.78181839),
+    float2(0.60000002, 0.39999962),
+    float2(0.61818182, 0.01818275),
+    float2(0.63636363, 0.63636398),
+    float2(0.65454543, 0.25454521),
+    float2(0.67272729, 0.87272835),
+    float2(0.69090909, 0.49090958),
+    float2(0.70909089, 0.10909081),
+    float2(0.72727275, 0.72727203),
+    float2(0.74545455, 0.34545517),
+    float2(0.76363635, 0.96363640),
+    float2(0.78181821, 0.58181763),
+    float2(0.80000001, 0.20000076),
+    float2(0.81818181, 0.81818199),
+    float2(0.83636361, 0.43636322),
+    float2(0.85454547, 0.05454636),
+    float2(0.87272727, 0.67272758),
+    float2(0.89090908, 0.29090881),
+    float2(0.90909094, 0.90909195),
+    float2(0.92727274, 0.52727318),
+    float2(0.94545454, 0.14545441),
+    float2(0.96363634, 0.76363754),
+    float2(0.98181820, 0.38181686)
+};
+
+// Loads elements from one of the precomputed tables for sequence lengths of 9, 10, 11.
+// Computes the values at runtime otherwise.
+// For sampling, the size of the point set is given by { k_FibonacciSeq[sequenceLength - 1] }.
+float2 Fibonacci2d(uint i, uint sequenceLength)
+{
+    int fibN1 = k_FibonacciSeq[sequenceLength - 1];
+    int fibN2 = k_FibonacciSeq[sequenceLength - 2];
+
+    switch (fibN1)
+    {
+        case 21: return k_Fibonacci2dSeq21[i];
+        case 34: return k_Fibonacci2dSeq34[i];
+        case 55: return k_Fibonacci2dSeq55[i];
+        default: Fibonacci2dSeq(fibN1, fibN2, i);
+    }
+}
+
+#endif // UNITY_FIBONACCI_INCLUDED
--- a/Assets/ScriptableRenderLoop/ShaderLibrary/Fibonacci2D.hlsl.meta
+++ b/Assets/ScriptableRenderLoop/ShaderLibrary/Fibonacci2D.hlsl.meta
+fileFormatVersion: 2
+guid: 0d37afcf16b660e428d6540186f474e6
+timeCreated: 1482308948
+licenseType: Pro
+ShaderImporter:
+  defaultTextures: []
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: