From d1cc4a53f5492d95c260a7871cc030c9b1b0a6e9 Mon Sep 17 00:00:00 2001
From: Andreas Grois <andi@grois.info>
Date: Sat, 10 Mar 2018 15:59:48 +0100
Subject: Add color scaling option (as 8 bit per channel is not really much)

---
 BuddhaTest/include/Helpers.h  | 2 +-
 BuddhaTest/src/BuddhaTest.cpp | 3 ++-
 BuddhaTest/src/Helpers.cpp    | 6 +++---
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/BuddhaTest/include/Helpers.h b/BuddhaTest/include/Helpers.h
index e4b7ffd..a25aa31 100644
--- a/BuddhaTest/include/Helpers.h
+++ b/BuddhaTest/include/Helpers.h
@@ -9,7 +9,7 @@ namespace Helpers
 	GLuint LoadShaders(const char * vertex_file_path, const char * fragment_file_path);
     GLuint LoadComputeShader(const char * compute_file_path, unsigned int localSizeX, unsigned int localSizeY, unsigned int localSizeZ);
 
-    void WriteOutputPNG(const std::vector<uint32_t>& data, unsigned int width, unsigned int bufferHeight, double gamma);
+    void WriteOutputPNG(const std::vector<uint32_t>& data, unsigned int width, unsigned int bufferHeight, double gamma, double colorScale);
 
     /** Wraps around a C file descriptor. Libpng could be taught to use C++ streams, but I'm too lazy and rather wrap this ugly thing up, so it gets cleaned... */
     class ScopedCFileDescriptor
diff --git a/BuddhaTest/src/BuddhaTest.cpp b/BuddhaTest/src/BuddhaTest.cpp
index 9ac6ae3..32bd927 100644
--- a/BuddhaTest/src/BuddhaTest.cpp
+++ b/BuddhaTest/src/BuddhaTest.cpp
@@ -30,6 +30,7 @@ int main()
     unsigned int globalWorkGroupSizeZ = 1;
 
     double pngGamma = 1.0;
+    double pngColorScale = 2.0;
 
 	GLFWwindow* window;
 
@@ -183,7 +184,7 @@ int main()
     {
         std::vector<uint32_t> readBackBuffer(pixelCount);
         glGetBufferSubData(GL_SHADER_STORAGE_BUFFER,4*2,4 * pixelCount,readBackBuffer.data()); //offset of 2*4, that's the dimension integers.
-        Helpers::WriteOutputPNG(readBackBuffer,bufferWidth,bufferHeight, pngGamma);
+        Helpers::WriteOutputPNG(readBackBuffer,bufferWidth,bufferHeight, pngGamma, pngColorScale);
     }
 
     //a bit of cleanup
diff --git a/BuddhaTest/src/Helpers.cpp b/BuddhaTest/src/Helpers.cpp
index bde6b8a..eacaf5d 100644
--- a/BuddhaTest/src/Helpers.cpp
+++ b/BuddhaTest/src/Helpers.cpp
@@ -155,7 +155,7 @@ namespace Helpers
 		return ProgramID;
 	}
 
-    void WriteOutputPNG(const std::vector<uint32_t>& data, unsigned int width, unsigned int bufferHeight, double gamma)
+    void WriteOutputPNG(const std::vector<uint32_t>& data, unsigned int width, unsigned int bufferHeight, double gamma, double colorScale)
     {
         std::vector<png_byte> pngData(3*width*2*bufferHeight);
         std::vector<png_byte *> rows{2*bufferHeight};
@@ -171,9 +171,9 @@ namespace Helpers
         }
         for(unsigned int i = 0; i < data.size();++i)
         {
-            if(fabs(gamma - 1.0) > 0.0001)
+            if(fabs(gamma - 1.0) > 0.0001 || fabs(colorScale - 1.0) > 0.0001)
             {
-                pngData[data.size() + i] = 255.0 * pow(static_cast<double>(data[i])/static_cast<double>(maxValue),gamma);
+                pngData[data.size() + i] = 255.0 * pow(std::min(1.0,colorScale*static_cast<double>(data[i])/static_cast<double>(maxValue)),gamma);
             }
             else
             {
-- 
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