From 9781fe55ea606cb7d2c23bd0d191ca7d18c31bf4 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Mon, 20 Jun 2011 12:36:53 +0000
Subject: [PATCH] From Farshid Lashkari, BGR write support for BMP, PNG and TGA

---
 src/osgPlugins/bmp/ReaderWriterBMP.cpp | 17 +++++++++++++----
 src/osgPlugins/png/ReaderWriterPNG.cpp |  2 ++
 src/osgPlugins/tga/ReaderWriterTGA.cpp | 19 ++++++++++++++-----
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/src/osgPlugins/bmp/ReaderWriterBMP.cpp b/src/osgPlugins/bmp/ReaderWriterBMP.cpp
index 97f34f94d..934d57c12 100644
--- a/src/osgPlugins/bmp/ReaderWriterBMP.cpp
+++ b/src/osgPlugins/bmp/ReaderWriterBMP.cpp
@@ -513,7 +513,16 @@ static bool bmp_save(const osg::Image& img, std::ostream& fout)
         fout.write((char*) &dib, sizeof(dib));
     }
 
-    const unsigned int channelsPerPixel = img.computeNumComponents(img.getPixelFormat());
+    unsigned int pixelFormat = img.getPixelFormat();
+
+    unsigned int r = 0, g = 1, b = 2;
+    if ( pixelFormat == GL_BGR || pixelFormat == GL_BGRA )
+    {
+        r = 2;
+        b = 0;
+    }
+
+    const unsigned int channelsPerPixel = img.computeNumComponents(pixelFormat);
 
     std::vector<unsigned char> rowBuffer(bytesPerRowAlign);
     for (int y = 0; y < img.t(); ++y)
@@ -523,9 +532,9 @@ static bool bmp_save(const osg::Image& img, std::ostream& fout)
         {
             // RGB -> BGR
             unsigned int rowOffs = x * 3, imgOffs = x * channelsPerPixel;
-            rowBuffer[rowOffs + 2] = imgp[imgOffs + 0];
-            rowBuffer[rowOffs + 1] = imgp[imgOffs + 1];
-            rowBuffer[rowOffs + 0] = imgp[imgOffs + 2];
+            rowBuffer[rowOffs + 2] = imgp[imgOffs + r];
+            rowBuffer[rowOffs + 1] = imgp[imgOffs + g];
+            rowBuffer[rowOffs + 0] = imgp[imgOffs + b];
         }
         fout.write((char*) &*rowBuffer.begin(), rowBuffer.size());
     }
diff --git a/src/osgPlugins/png/ReaderWriterPNG.cpp b/src/osgPlugins/png/ReaderWriterPNG.cpp
index 48de02cf6..8ab3da3d4 100644
--- a/src/osgPlugins/png/ReaderWriterPNG.cpp
+++ b/src/osgPlugins/png/ReaderWriterPNG.cpp
@@ -118,6 +118,8 @@ class ReaderWriterPNG : public osgDB::ReaderWriter
                 case(GL_LUMINANCE_ALPHA): color = PNG_COLOR_TYPE_GRAY_ALPHA ; break;
                 case(GL_RGB): color = PNG_COLOR_TYPE_RGB; break;
                 case(GL_RGBA): color = PNG_COLOR_TYPE_RGB_ALPHA; break;
+                case(GL_BGR): color = PNG_COLOR_TYPE_RGB; png_set_bgr(png); break;
+                case(GL_BGRA): color = PNG_COLOR_TYPE_RGB_ALPHA; png_set_bgr(png); break;
                 default: return WriteResult::ERROR_IN_WRITING_FILE; break;                
             }
 
diff --git a/src/osgPlugins/tga/ReaderWriterTGA.cpp b/src/osgPlugins/tga/ReaderWriterTGA.cpp
index e56995cad..57fc5d7b1 100644
--- a/src/osgPlugins/tga/ReaderWriterTGA.cpp
+++ b/src/osgPlugins/tga/ReaderWriterTGA.cpp
@@ -549,8 +549,9 @@ class ReaderWriterTGA : public osgDB::ReaderWriter
             // Other data types can be added soon with different options
             // The format description can be found at:
             // http://local.wasp.uwa.edu.au/~pbourke/dataformats/tga/
+            unsigned int pixelFormat = image.getPixelFormat();
             int width = image.s(), height = image.t();
-            int numPerPixel = image.computeNumComponents(image.getPixelFormat());
+            int numPerPixel = image.computeNumComponents(pixelFormat);
             int pixelMultiplier = (image.getDataType()==GL_FLOAT ? 255 : 1);
             const unsigned char* data = image.data();
             if ( !data ) return false;
@@ -569,6 +570,14 @@ class ReaderWriterTGA : public osgDB::ReaderWriter
             fout.put(numPerPixel * 8);  // Image pixel size
             fout.put(0);  // Image descriptor
             
+            // Swap red/blue channels for BGR images
+            int r = 0, g = 1, b = 2;
+            if( pixelFormat == GL_BGR || pixelFormat == GL_BGRA )
+            {
+                r = 2;
+                b = 0;
+            }
+
             // Data
             for (int y=0; y<height; ++y)
             {
@@ -579,12 +588,12 @@ class ReaderWriterTGA : public osgDB::ReaderWriter
                     switch ( numPerPixel )
                     {
                     case 3:  // BGR
-                        fout.put(ptr[off+2] * pixelMultiplier); fout.put(ptr[off+1] * pixelMultiplier);
-                        fout.put(ptr[off+0] * pixelMultiplier);
+                        fout.put(ptr[off+b] * pixelMultiplier); fout.put(ptr[off+g] * pixelMultiplier);
+                        fout.put(ptr[off+r] * pixelMultiplier);
                         break;
                     case 4:  // BGRA
-                        fout.put(ptr[off+2] * pixelMultiplier); fout.put(ptr[off+1] * pixelMultiplier);
-                        fout.put(ptr[off+0] * pixelMultiplier); fout.put(ptr[off+3] * pixelMultiplier);
+                        fout.put(ptr[off+b] * pixelMultiplier); fout.put(ptr[off+g] * pixelMultiplier);
+                        fout.put(ptr[off+r] * pixelMultiplier); fout.put(ptr[off+3] * pixelMultiplier);
                         break;
                     default:
                         return false;