Added HSI chromaticity option

papadanku · May 1, 2024 · 2f43d7f · 2f43d7f
1 parent 766bd71
commit 2f43d7f
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Showing 6 changed files with 51 additions and 21 deletions.
diff --git a/shaders/cBlockMatching.fx b/shaders/cBlockMatching.fx
@@ -47,7 +47,7 @@ namespace cBlockMatching
     float2 PS_Normalize(VS2PS_Quad Input) : SV_TARGET0
     {
         float3 Color = tex2D(CShade_SampleColorTex, Input.Tex0).rgb;
-        return GetSumChromaticity(Color, 3).xy;
+        return GetSphericalRG(Color).xy;
     }
 
     float4 PS_Copy_0(VS2PS_Quad Input) : SV_TARGET0

diff --git a/shaders/cChromaticity.fx b/shaders/cChromaticity.fx
@@ -9,7 +9,7 @@ uniform int _Select <
     ui_label = "Method";
     ui_tooltip = "Select Chromaticity";
     ui_type = "combo";
-    ui_items = " Length (XY)\0 Length (XYZ)\0 Average (XY)\0 Average (XYZ)\0 Sum (XY)\0 Sum (XYZ)\0 Max (XY)\0 Max (XYZ)\0 Ratio (XY)\0 Spherical (XY)\0 Hue-Saturation (HSL)\0 Hue-Saturation (HSV)\0 CoCg (XY)\0 CrCb (XY)\0";
+    ui_items = " Length (XY)\0 Length (XYZ)\0 Average (XY)\0 Average (XYZ)\0 Sum (XY)\0 Sum (XYZ)\0 Max (XY)\0 Max (XYZ)\0 Ratio (XY)\0 Spherical (XY)\0 Hue-Saturation (HSI)\0 Hue-Saturation (HSL)\0 Hue-Saturation (HSV)\0 CoCg (XY)\0 CrCb (XY)\0";
 > = 0;
 
 /*
@@ -54,16 +54,19 @@ float4 PS_Chromaticity(VS2PS_Quad Input) : SV_TARGET0
         case 9: // Spherical (XY)
             Chromaticity.rg = GetSphericalRG(Color);
             break;
-        case 10: // Hue-Saturation (HSL)
+        case 10: // Hue-Saturation (HSI)
+            Chromaticity.rg = GetHSIfromRGB(Color).gg;
+            break;
+        case 11: // Hue-Saturation (HSL)
             Chromaticity.rg = GetHSLfromRGB(Color).rg;
             break;
-        case 11: // Hue-Saturation (HSV)
+        case 12: // Hue-Saturation (HSV)
             Chromaticity.rg = GetHSVfromRGB(Color).rg;
             break;
-        case 12: // CoCg (XY)
+        case 13: // CoCg (XY)
             Chromaticity.rg = GetCoCg(Gamma);
             break;
-        case 13: // CrCb (XY)
+        case 14: // CrCb (XY)
             Chromaticity.rg = GetCrCb(Gamma);
             break;
         default: // No Chromaticity

diff --git a/shaders/cMotionBlur.fx b/shaders/cMotionBlur.fx
@@ -73,7 +73,7 @@ namespace cMotionBlur
     float2 PS_Normalize(VS2PS_Quad Input) : SV_TARGET0
     {
         float3 Color = tex2D(CShade_SampleColorTex, Input.Tex0).rgb;
-        return GetSumChromaticity(Color, 3).xy;
+        return GetSphericalRG(Color).xy;
     }
 
     float2 PS_HBlur_Prefilter(VS2PS_Quad Input) : SV_TARGET0

diff --git a/shaders/cOpticalFlow.fx b/shaders/cOpticalFlow.fx
@@ -152,7 +152,7 @@ namespace cOpticalFlow
     float2 PS_Normalize(VS2PS_Quad Input) : SV_TARGET0
     {
         float3 Color = tex2D(CShade_SampleColorTex, Input.Tex0).rgb;
-        return GetSumChromaticity(Color, 3).xy;
+        return GetSphericalRG(Color).xy;
     }
 
     float2 PS_HBlur_Prefilter(VS2PS_Quad Input) : SV_TARGET0

diff --git a/shaders/kDatamosh.fx b/shaders/kDatamosh.fx
@@ -135,7 +135,7 @@ namespace kDatamosh
     float2 PS_Normalize(VS2PS_Quad Input) : SV_TARGET0
     {
         float3 Color = tex2D(CShade_SampleColorTex, Input.Tex0).rgb;
-        return GetSumChromaticity(Color, 3).xy;
+        return GetSphericalRG(Color).xy;
     }
 
     float2 PS_HBlur_Prefilter(VS2PS_Quad Input) : SV_TARGET0

diff --git a/shaders/shared/cImageProcessing.fxh b/shaders/shared/cImageProcessing.fxh
@@ -378,18 +378,6 @@
         return SatRGB;
     }
 
-    float2 GetSphericalRG(float3 Color)
-    {
-        const float IHalfPi = 1.0 / acos(0.0);
-        const float2 White = acos(rsqrt(float2(2.0, 3.0)));
-
-        float2 DotC = 0.0;
-        DotC.x = dot(Color.xy, Color.xy);
-        DotC.y = dot(Color.xyz, Color.xyz);
-        float2 P = (DotC == 0.0) ? White : acos(abs(Color.xz * rsqrt(DotC)));
-        return saturate(P * IHalfPi);
-    }
-
     /*
         Color-space conversion
         ---
@@ -453,4 +441,43 @@
         Output.z = Lightness;
         return Output;
     }
+
+    /*
+        This code is based on the algorithm described in the following paper:
+        Author(s): Joost van de Weijer, T. Gevers
+        Title: "Robust optical flow from photometric invariants"
+        Year: 2004
+        DOI: 10.1109/ICIP.2004.1421433
+    */
+
+    float2 GetSphericalRG(float3 Color)
+    {
+        const float HalfPi = 1.0 / acos(0.0);
+        const float2 White = acos(rsqrt(float2(2.0, 3.0)));
+
+        // Precalculate (x*x + y*y)^0.5 and (x*x + y*y + z*z)^0.5
+        float L1 = length(Color.rg);
+        float L2 = length(Color.rgb);
+
+        float2 Angles = 0.0;
+        Angles[0] = (L1 == 0.0) ? 1.0 / sqrt(2.0) : Color.g / L1;
+        Angles[1] = (L2 == 0.0) ? 1.0 / sqrt(3.0) : L1 / L2;
+
+        return saturate(asin(abs(Angles)) * HalfPi);
+    }
+
+    float3 GetHSIfromRGB(float3 Color)
+    {
+        float3 O = Color.rrr;
+        O += (Color.ggg * float3(-1.0, 1.0, 1.0));
+        O += (Color.bbb * float3(0.0, -2.0, 1.0));
+        O *= rsqrt(float3(2.0, 6.0, 3.0));
+
+        float H = atan(O.x/O.y) / acos(0.0);
+        H = (H * 0.5) + 0.5; // We also scale to [0,1] range
+        float S = length(O.xy);
+        float I = O.z;
+
+        return float3(H, S, I);
+    }
 #endif