From 2648723c83dce98a687c50b896dd842c7fb36b23 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 14 Apr 2011 15:22:43 +0000
Subject: [PATCH] Cleaned up DXT1 support

---
 src/osg/Image.cpp                      | 14 ++------------
 src/osg/dxtctool.cpp                   |  5 +++++
 src/osgPlugins/dds/ReaderWriterDDS.cpp |  8 ++++----
 3 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/src/osg/Image.cpp b/src/osg/Image.cpp
index 6602319cc..ca11ac6d9 100644
--- a/src/osg/Image.cpp
+++ b/src/osg/Image.cpp
@@ -633,18 +633,7 @@ void Image::setInternalTextureFormat(GLint internalFormat)
 
 void Image::setPixelFormat(GLenum pixelFormat)
 {
-    if (_pixelFormat==pixelFormat) return; // do nothing if the same.
-
-    if (_pixelFormat==0 || computeNumComponents(_pixelFormat)==computeNumComponents(pixelFormat))
-    {
-       // if the two formats have the same number of componets then
-       // we can do a straight swap.
-        _pixelFormat = pixelFormat;
-    }
-    else
-    {
-        OSG_WARN<<"Image::setPixelFormat(..) - warning, attempt to reset the pixel format with a different number of components."<<std::endl;
-    }
+    _pixelFormat = pixelFormat;
 }
 
 void Image::setDataType(GLenum dataType)
@@ -1256,6 +1245,7 @@ bool Image::isImageTranslucent() const
         case(GL_BGR):
             return false;
         case(GL_COMPRESSED_RGB_S3TC_DXT1_EXT):
+            return false;
         case(GL_COMPRESSED_RGBA_S3TC_DXT1_EXT):
         case(GL_COMPRESSED_RGBA_S3TC_DXT3_EXT):
         case(GL_COMPRESSED_RGBA_S3TC_DXT5_EXT):
diff --git a/src/osg/dxtctool.cpp b/src/osg/dxtctool.cpp
index ac333dd94..9ed1189df 100644
--- a/src/osg/dxtctool.cpp
+++ b/src/osg/dxtctool.cpp
@@ -173,6 +173,8 @@ bool CompressedImageTranslucent(size_t width, size_t height, GLenum format, void
     switch(format)
     {
         case(GL_COMPRESSED_RGB_S3TC_DXT1_EXT):
+            return false;
+
         case(GL_COMPRESSED_RGBA_S3TC_DXT1_EXT):
         {
             const DXT1TexelsBlock *texelsBlock = reinterpret_cast<const DXT1TexelsBlock*>(imageData);
@@ -209,10 +211,13 @@ bool CompressedImageTranslucent(size_t width, size_t height, GLenum format, void
             }
             return false;
         }
+
         case(GL_COMPRESSED_RGBA_S3TC_DXT3_EXT):
             return true;
+
         case(GL_COMPRESSED_RGBA_S3TC_DXT5_EXT):
             return true;
+
         default:
             break;
     }
diff --git a/src/osgPlugins/dds/ReaderWriterDDS.cpp b/src/osgPlugins/dds/ReaderWriterDDS.cpp
index 8c535cf77..68fe9467c 100644
--- a/src/osgPlugins/dds/ReaderWriterDDS.cpp
+++ b/src/osgPlugins/dds/ReaderWriterDDS.cpp
@@ -924,10 +924,10 @@ public:
     ReaderWriterDDS()
     {
         supportsExtension("dds","DDS image format");
-        supportsOption("dds_dxt1_rgb","set the pixel format of DXT1 encoded images to be RGB");
-        supportsOption("dds_dxt1_rgba","set the pixel format of DXT1 encoded images to be RGBA");
-        supportsOption("dds_dxt1_detect_rgba","For DXT1 encode images set the pixel format according to presence of transparent pixels.");
-        supportsOption("dds_flip","flip the image about the horizontl axis");
+        supportsOption("dds_dxt1_rgb","Set the pixel format of DXT1 encoded images to be RGB variant of DXT1");
+        supportsOption("dds_dxt1_rgba","Set the pixel format of DXT1 encoded images to be RGBA variant of DXT1");
+        supportsOption("dds_dxt1_detect_rgba","For DXT1 encode images set the pixel format according to presence of transparent pixels");
+        supportsOption("dds_flip","Flip the image about the horizontl axis");
     }
 
     virtual const char* className() const