From e67466a74fd6f9f25149859b10d2c9f6e9ee1ef3 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 21 Nov 2014 16:27:29 +0000
Subject: [PATCH] From Sebastian Messerschmidt, "Added setColor function to
 modify an image based on texture coordinates, parallel to the getColor
 functionality."

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14517 16af8721-9629-0410-8352-f15c8da7e697
---
 include/osg/Image | 20 ++++++++++++++------
 src/osg/Image.cpp | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/include/osg/Image b/include/osg/Image
index 4e01e3af1..cd3ea7d30 100644
--- a/include/osg/Image
+++ b/include/osg/Image
@@ -373,6 +373,14 @@ class OSG_EXPORT Image : public BufferData
         /** Get the color value for specified texcoord.*/
         Vec4 getColor(const Vec3& texcoord) const;
 
+         /** Set the color value for specified texcoord.*/
+        void setColor(const osg::Vec4& color, unsigned int s, unsigned int t=0, unsigned int r=0);
+
+         /** Set the color value for specified texcoord.*/
+        void setColor(const osg::Vec4& color, const osg::Vec2& texcoord ) { setColor(color, osg::Vec3(texcoord, 0.0f)); }
+
+         /** Set the color value for specified texcoord.*/
+        void setColor(const osg::Vec4& color, const osg::Vec3& texcoord );
 
         /** Flip the image horizontally, around s dimension. */
         void flipHorizontal();
@@ -476,15 +484,15 @@ class OSG_EXPORT Image : public BufferData
 
         /** Pass frame information to the custom Image classes, to be called only when objects associated with imagery are not culled.*/
         virtual void setFrameLastRendered(const osg::FrameStamp* /*frameStamp*/) {}
-        
+
         class DimensionsChangedCallback : public osg::Referenced {
         public:
             DimensionsChangedCallback() : osg::Referenced() {}
             virtual void operator()(osg::Image* image) = 0;
         };
-        
+
         typedef std::vector< osg::ref_ptr<DimensionsChangedCallback> > DimensionsChangedCallbackVector;
-        
+
         void addDimensionsChangedCallback(DimensionsChangedCallback* cb);
         void removeDimensionsChangedCallback(DimensionsChangedCallback* cb);
 
@@ -493,8 +501,8 @@ class OSG_EXPORT Image : public BufferData
         virtual ~Image();
 
         Image& operator = (const Image&) { return *this; }
-        
-        void handleDimensionsChangedCallbacks() 
+
+        void handleDimensionsChangedCallbacks()
         {
             for(DimensionsChangedCallbackVector::iterator i = _dimensionsChangedCallbacks.begin(); i != _dimensionsChangedCallbacks.end(); ++i)
             {
@@ -523,7 +531,7 @@ class OSG_EXPORT Image : public BufferData
         void setData(unsigned char* data,AllocationMode allocationMode);
 
         MipmapDataType _mipmapData;
-        
+
         DimensionsChangedCallbackVector _dimensionsChangedCallbacks;
 };
 
diff --git a/src/osg/Image.cpp b/src/osg/Image.cpp
index 20144a931..6e21a7991 100644
--- a/src/osg/Image.cpp
+++ b/src/osg/Image.cpp
@@ -1926,6 +1926,51 @@ Vec4 Image::getColor(const Vec3& texcoord) const
     return getColor(s,t,r);
 }
 
+
+template <typename T>
+void _writeColor(GLenum pixelFormat, T* data, float scale, const Vec4& c)
+{
+    switch(pixelFormat)
+    {
+    case(GL_DEPTH_COMPONENT):   //intentionally fall through and execute the code for GL_LUMINANCE
+    case(GL_LUMINANCE):         { (*data++) = c[0] * scale; } break;
+    case(GL_ALPHA):             { (*data++) = c[3] * scale; } break;
+    case(GL_LUMINANCE_ALPHA):   { (*data++) = c[0] * scale;  (*data++) = c[3] * scale; } break;
+    case(GL_RGB):               { (*data++) = c[0] *scale; (*data++) = c[1] *scale; (*data++) = c[2] *scale;} break;
+    case(GL_RGBA):              { (*data++) = c[0] *scale; (*data++) = c[1] *scale; (*data++) = c[2] *scale; (*data++) = c[3] *scale;} break;
+    case(GL_BGR):               { (*data++) = c[2] *scale; (*data++) = c[1] *scale; (*data++) = c[0] *scale;} break;
+    case(GL_BGRA):              { (*data++) = c[2] *scale; (*data++) = c[1] *scale; (*data++) = c[0] *scale; (*data++) = c[3] *scale;} break;
+    }
+
+}
+
+
+void Image::setColor( const Vec4& color, unsigned int s, unsigned int t/*=0*/, unsigned int r/*=0*/ )
+{
+    unsigned char* ptr = data(s,t,r);
+
+    switch(getDataType())
+    {
+    case(GL_BYTE):              return _writeColor(getPixelFormat(), (char*)ptr,             128.0f, color);
+    case(GL_UNSIGNED_BYTE):     return _writeColor(getPixelFormat(), (unsigned char*)ptr,    255.0f, color);
+    case(GL_SHORT):             return _writeColor(getPixelFormat(), (short*)ptr,            32768.0f, color);
+    case(GL_UNSIGNED_SHORT):    return _writeColor(getPixelFormat(), (unsigned short*)ptr,   65535.0f, color);
+    case(GL_INT):               return _writeColor(getPixelFormat(), (int*)ptr,              2147483648.0f, color);
+    case(GL_UNSIGNED_INT):      return _writeColor(getPixelFormat(), (unsigned int*)ptr,     4294967295.0f, color);
+    case(GL_FLOAT):             return _writeColor(getPixelFormat(), (float*)ptr,            1.0f, color);
+    case(GL_DOUBLE):            return _writeColor(getPixelFormat(), (double*)ptr,           1.0f, color);
+    }
+}
+
+void Image::setColor( const Vec4& color, const Vec3& texcoord )
+{
+    int s = int(texcoord.x()*float(_s - 1 )) % _s;
+    int t = int(texcoord.y()*float(_t - 1))  % _t;
+    int r = int(texcoord.z()*float(_r - 1))  % _r;
+
+    return setColor(color, s,t,r);
+}
+
 void Image::addDimensionsChangedCallback(DimensionsChangedCallback* cb)
 {
     _dimensionsChangedCallbacks.push_back(cb);