Add tonemapper that hashes to a random color

Author: a-e-k

include/tev/Common.h

@@ -373,6 +373,7 @@ enum ETonemap : int {
     Gamma,
     FalseColor,
     PositiveNegative,
+    Hash,
 
     // This enum value should never be used directly.
     // It facilitates looping over all members of this enum.

src/Common.cpp

@@ -232,6 +232,8 @@ ETonemap toTonemap(string name) {
         return FalseColor;
     } else if (name == "POSITIVENEGATIVE" || name == "POSNEG" || name == "PN" ||name == "+-") {
         return PositiveNegative;
+    } else if (name == "HASH") {
+        return Hash;
     } else {
         return SRGB;
     }

src/ImageCanvas.cpp

@@ -558,6 +558,17 @@ Vector3f ImageCanvas::applyTonemap(const Vector3f& value, float gamma, ETonemap
                 result = {-2.0f * mean(min(value, Vector3f{0.0f})), 2.0f * mean(max(value, Vector3f{0.0f})), 0.0f};
                 break;
             }
+        case ETonemap::Hash:
+            {
+                static const auto fract = [](float x){ return x - floor(x); };
+                result = value;
+                result *= {abs(result.x()) < 1024.0f ? 1.0f : 1.0f / 1024.0f, abs(result.y()) < 1024.0f ? 1.0f : 1.0f / 1024.0f, abs(result.z()) < 1024.0f ? 1.0f : 1.0f / 1024.0f};
+                result *= {abs(result.x()) < 1024.0f ? 1.0f : 1.0f / 1024.0f, abs(result.y()) < 1024.0f ? 1.0f : 1.0f / 1024.0f, abs(result.z()) < 1024.0f ? 1.0f : 1.0f / 1024.0f};
+                result *= {abs(result.x()) < 1024.0f ? 1.0f : 1.0f / 1024.0f, abs(result.y()) < 1024.0f ? 1.0f : 1.0f / 1024.0f, abs(result.z()) < 1024.0f ? 1.0f : 1.0f / 1024.0f};
+                result = abs(fract(dot(result, Vector3f{115.191742f, 64.0546951f, 124.512291f})) - 0.5f) * Vector3f{1368.46143f, 1523.2019f, 1034.50476f};
+                result = {2.0f * abs(fract(result.x()) - 0.5f), 2.0f * abs(fract(result.y()) - 0.5f), 2.0f * abs(fract(result.z()) - 0.5f)};
+                break;
+            }
         default:
             throw runtime_error{"Invalid tonemap selected."};
     }

src/ImageViewer.cpp

@@ -25,7 +25,7 @@ using namespace std;
 
 namespace tev {
 
-static const int SIDEBAR_MIN_WIDTH = 230;
+static const int SIDEBAR_MIN_WIDTH = 245;
 static const float CROP_MIN_SIZE = 3;
 
 ImageViewer::ImageViewer(
@@ -214,7 +214,7 @@ ImageViewer::ImageViewer(
     // Tonemap options
     {
         mTonemapButtonContainer = new Widget{mSidebarLayout};
-        mTonemapButtonContainer->set_layout(new GridLayout{Orientation::Horizontal, 4, Alignment::Fill, 5, 2});
+        mTonemapButtonContainer->set_layout(new GridLayout{Orientation::Horizontal, 5, Alignment::Fill, 5, 2});
 
         auto makeTonemapButton = [&](const string& name, function<void()> callback) {
             auto button = new Button{mTonemapButtonContainer, name};
@@ -228,6 +228,7 @@ ImageViewer::ImageViewer(
         makeTonemapButton("Gamma", [this]() { setTonemap(ETonemap::Gamma); });
         makeTonemapButton("FC",    [this]() { setTonemap(ETonemap::FalseColor); });
         makeTonemapButton("+/-",   [this]() { setTonemap(ETonemap::PositiveNegative); });
+        makeTonemapButton("Hash",  [this]() { setTonemap(ETonemap::Hash); });
 
         setTonemap(ETonemap::SRGB);
 
@@ -244,7 +245,10 @@ ImageViewer::ImageViewer(
             "False-color visualization\n\n"
 
             "+/-\n"
-            "Positive=Green, Negative=Red"
+            "Positive=Green, Negative=Red\n\n"
+
+            "Hash\n"
+            "Hash values to random colors"
         );
     }
 

src/UberShader.cpp

@@ -18,7 +18,8 @@ UberShader::UberShader(RenderPass* renderPass) {
 #   elif defined(NANOGUI_USE_GLES)
     std::string preamble =
         R"(#version 100
-        precision highp float;)";
+        precision highp float;
+        precision highp sampler2D;)";
 #   endif
         auto vertexShader = preamble +
             R"glsl(
@@ -51,6 +52,7 @@ UberShader::UberShader(RenderPass* renderPass) {
             #define GAMMA       1
             #define FALSE_COLOR 2
             #define POS_NEG     3
+            #define HASH        4
 
             #define ERROR                   0
             #define ABSOLUTE_ERROR          1
@@ -117,6 +119,13 @@ UberShader::UberShader(RenderPass* renderPass) {
                 }
             }
 
+            vec3 hash(vec3 co){
+                co *= mix(vec3(1.0), vec3(1.0 / 1024.0), step(1024.0, abs(co)));
+                co *= mix(vec3(1.0), vec3(1.0 / 1024.0), step(1024.0, abs(co)));
+                co *= mix(vec3(1.0), vec3(1.0 / 1024.0), step(1024.0, abs(co)));
+                return 2.0 * abs(fract(abs(fract(dot(co, vec3(115.191742, 64.0546951, 124.512291))) - 0.5) * vec3(1368.46143, 1523.2019, 1034.50476)) - 0.5);
+            }
+
             vec3 applyTonemap(vec3 col, vec4 background) {
                 if (tonemap == SRGB) {
                     col = col +
@@ -129,6 +138,8 @@ UberShader::UberShader(RenderPass* renderPass) {
                     return falseColor(log2(average(col)+0.03125) / 10.0 + 0.5) + (background.rgb - falseColor(0.0)) * background.a;
                 } else if (tonemap == POS_NEG) {
                     return vec3(-average(min(col, vec3(0.0))) * 2.0, average(max(col, vec3(0.0))) * 2.0, 0.0) + background.rgb * background.a;
+                } else if (tonemap == HASH) {
+                    return hash(col) + (background.rgb - hash(vec3(offset))) * background.a;
                 }
                 return vec3(0.0);
             }
@@ -230,6 +241,7 @@ UberShader::UberShader(RenderPass* renderPass) {
             #define GAMMA       1
             #define FALSE_COLOR 2
             #define POS_NEG     3
+            #define HASH        4
 
             #define ERROR                   0
             #define ABSOLUTE_ERROR          1
@@ -272,6 +284,13 @@ UberShader::UberShader(RenderPass* renderPass) {
                 }
             }
 
+            float3 hash(float3 co){
+                co *= mix(float3(1.0f), float3(1.0f / 1024.0f), step(1024.0f, abs(co)));
+                co *= mix(float3(1.0f), float3(1.0f / 1024.0f), step(1024.0f, abs(co)));
+                co *= mix(float3(1.0f), float3(1.0f / 1024.0f), step(1024.0f, abs(co)));
+                return 2.0f * abs(fract(abs(fract(dot(co.xyz, float3(115.191742f, 64.0546951f, 124.512291f))) - 0.5f) * float3(1368.46143f, 1523.2019f, 1034.50476f)) - 0.5f);
+            }
+
             float3 applyTonemap(float3 col, float4 background, int tonemap, float offset, float gamma, texture2d<float, access::sample> colormap, sampler colormapSampler) {
                 switch (tonemap) {
                     case SRGB:
@@ -286,6 +305,8 @@ UberShader::UberShader(RenderPass* renderPass) {
                         return falseColor(log2(average(col)+0.03125f) / 10.0f + 0.5f, colormap, colormapSampler) + (background.rgb - falseColor(0.0f, colormap, colormapSampler)) * background.a;
                     case POS_NEG:
                         return float3(-average(min(col, float3(0.0f))) * 2.0f, average(max(col, float3(0.0f))) * 2.0f, 0.0f) + background.rgb * background.a;
+                    case HASH:
+                        return hash(col) + (background.rgb - hash(float3(offset))) * background.a;
                 }
                 return float3(0.0f);
             }

src/main.cpp

@@ -233,6 +233,7 @@ int mainFunc(const vector<string>& arguments) {
         "Gamma  - Gamma curve\n"
         "FC     - False Color\n"
         "PN     - Positive=Green, Negative=Red\n"
+        "Hash   - Hash values to random colors\n"
         "Default is sRGB.",
         {'t', "tonemap"},
     };