From 8a0a3ca94bdd26057ff1ed5f9e13273cc0476e10 Mon Sep 17 00:00:00 2001
From: Andrew Kensler <andrew@eastfarthing.com>
Date: Wed, 10 Jul 2024 22:27:15 -0700
Subject: [PATCH] Add tonemapper that hashes to a random color

---
 include/tev/Common.h |  1 +
 src/Common.cpp       |  2 ++
 src/ImageViewer.cpp  | 10 +++++++---
 src/UberShader.cpp   | 14 ++++++++++++++
 src/main.cpp         |  1 +
 5 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/include/tev/Common.h b/include/tev/Common.h
index f6a3837..62c352b 100644
--- a/include/tev/Common.h
+++ b/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.
diff --git a/src/Common.cpp b/src/Common.cpp
index 42b5eb2..84cff39 100644
--- a/src/Common.cpp
+++ b/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;
     }
diff --git a/src/ImageViewer.cpp b/src/ImageViewer.cpp
index 3871d26..2be6042 100644
--- a/src/ImageViewer.cpp
+++ b/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"
         );
     }
 
diff --git a/src/UberShader.cpp b/src/UberShader.cpp
index 6a1167d..09cdab4 100644
--- a/src/UberShader.cpp
+++ b/src/UberShader.cpp
@@ -51,6 +51,7 @@ 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 +118,10 @@ UberShader::UberShader(RenderPass* renderPass) {
                 }
             }
 
+            vec3 hash(vec3 co){
+                return fract(cos(dot(co.xyz, vec3(61.5499458, -40.7123604, 34.8567848))) * vec3(-41882.2148, 62285.1367, 38605.582));
+            }
+
             vec3 applyTonemap(vec3 col, vec4 background) {
                 if (tonemap == SRGB) {
                     col = col +
@@ -129,6 +134,8 @@ 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 +237,7 @@ 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 +280,10 @@ UberShader::UberShader(RenderPass* renderPass) {
                 }
             }
 
+            float3 hash(float3 co){
+                return fract(cos(dot(co.xyz, float3(61.5499458f, -40.7123604f, 34.8567848f))) * float3(-41882.2148f, 62285.1367f, 38605.582f));
+            }
+
             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 +298,8 @@ 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);
             }
diff --git a/src/main.cpp b/src/main.cpp
index 10d044a..40bd72b 100644
--- a/src/main.cpp
+++ b/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"},
     };