From 39b9351153a0498037ab4b1285efba7d813bf52c Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Tue, 28 May 2013 11:25:13 +0000
Subject: [PATCH] =?UTF-8?q?From=20Diane=20Delall=C3=A9e=20and=20Sukender,?=
 =?UTF-8?q?=20"1.=20Image.cpp=20Failure=20to=20perform=20a=20vertical=20fl?=
 =?UTF-8?q?ip=20on=20S3TC-DXTC=20now=20simply=20leaves=20the=20original=20?=
 =?UTF-8?q?image=20instead=20of=20corrupting=20it.=20Image.cpp=20was=20som?=
 =?UTF-8?q?etimes=20performing=20a=20"normal"=20(=3D=20for=20uncompressed?=
 =?UTF-8?q?=20images)=20vertical=20flip=20on=20S3TC-DXTC=20images,=20produ?=
 =?UTF-8?q?cing=20weird=20results.=20Actually,=20code=20was=20trying=20a?=
 =?UTF-8?q?=20"DXTC=20vertical=20flip"=20and=20relied=20on=20the=20result?=
 =?UTF-8?q?=20to=20call=20a=20"normal=20vertical=20flip".=20But=20when=20t?=
 =?UTF-8?q?he=20"DXTC=20v-flip"=20encounters=20an=20error,=20this=20is=20i?=
 =?UTF-8?q?s=20not=20necessarily=20because=20the=20image=20is=20not=20S3TC?=
 =?UTF-8?q?=20(ex:=20unhandled=20image=20dimensions)!=20So=20now=20the=20c?=
 =?UTF-8?q?ode=20simply=20does=20"if=20dxtc,=20then=20flip=5Fdxtc;=20else?=
 =?UTF-8?q?=20flip=5Fnormal;".?=
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Note from Robert Osfield, moved the isDXT function into the dxt_tool file and namespace.
---
 src/osg/Image.cpp    | 30 +++++++++++++++++++++++++++---
 src/osg/dxtctool.cpp |  1 +
 src/osg/dxtctool.h   | 19 ++++++++++++++++---
 3 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/src/osg/Image.cpp b/src/osg/Image.cpp
index 92f1ad496..65f2ad3ab 100644
--- a/src/osg/Image.cpp
+++ b/src/osg/Image.cpp
@@ -1404,14 +1404,23 @@ void Image::flipVertical()
     unsigned int rowSize = getRowSizeInBytes();
     unsigned int rowStep = getRowStepInBytes();
 
+    const bool dxtc(dxtc_tool::isDXTC(_pixelFormat));
     if (_mipmapData.empty())
     {
         // no mipmaps,
         // so we can safely handle 3d textures
         for(int r=0;r<_r;++r)
         {
-            if (!dxtc_tool::VerticalFlip(_s,_t,_pixelFormat,data(0,0,r)))
+            if (dxtc)
             {
+                if (!dxtc_tool::VerticalFlip(_s,_t,_pixelFormat,data(0,0,r)))
+                {
+                    OSG_NOTICE << "Notice Image::flipVertical(): Vertical flip do not succeed" << std::endl;
+                }
+            }
+            else
+            {
+                if (isCompressed()) OSG_NOTICE << "Notice Image::flipVertical(): image is compressed but normal v-flip is used" << std::endl;
                 // its not a compressed image, so implement flip oursleves.
                 unsigned char* top = data(0,0,r);
                 unsigned char* bottom = top + (_t-1)*rowStep;
@@ -1422,8 +1431,16 @@ void Image::flipVertical()
     }
     else if (_r==1)
     {
-        if (!dxtc_tool::VerticalFlip(_s,_t,_pixelFormat,_data))
+        if (dxtc)
         {
+            if (!dxtc_tool::VerticalFlip(_s,_t,_pixelFormat,_data))
+            {
+                OSG_NOTICE << "Notice Image::flipVertical(): Vertical flip do not succeed" << std::endl;
+            }
+        }
+        else
+        {
+            if (isCompressed()) OSG_NOTICE << "Notice Image::flipVertical(): image is compressed but normal v-flip is used" << std::endl;
             // its not a compressed image, so implement flip oursleves.
             unsigned char* top = data(0,0,0);
             unsigned char* bottom = top + (_t-1)*rowStep;
@@ -1441,7 +1458,14 @@ void Image::flipVertical()
             t >>= 1;
             if (s==0) s=1;
             if (t==0) t=1;
-            if (!dxtc_tool::VerticalFlip(s,t,_pixelFormat,_data+_mipmapData[i]))
+            if (dxtc)
+            {
+                if (!dxtc_tool::VerticalFlip(s,t,_pixelFormat,_data+_mipmapData[i]))
+                {
+                    OSG_NOTICE << "Notice Image::flipVertical(): Vertical flip do not succeed" << std::endl;
+                }
+            }
+            else
             {
                 // its not a compressed image, so implement flip oursleves.
                 unsigned char* top = _data+_mipmapData[i];
diff --git a/src/osg/dxtctool.cpp b/src/osg/dxtctool.cpp
index 2e4628c8d..7e486972a 100644
--- a/src/osg/dxtctool.cpp
+++ b/src/osg/dxtctool.cpp
@@ -17,6 +17,7 @@ namespace dxtc_tool {
     const size_t dxtc_pixels::BSIZE_ALPHA_DXT3 = 8;
     const size_t dxtc_pixels::BSIZE_ALPHA_DXT5 = 8;
 
+
 //////////////////////////////////////////////////////////////////////
 // Construction/Destruction
 //////////////////////////////////////////////////////////////////////
diff --git a/src/osg/dxtctool.h b/src/osg/dxtctool.h
index 9251064ac..5d5f252d5 100644
--- a/src/osg/dxtctool.h
+++ b/src/osg/dxtctool.h
@@ -73,10 +73,9 @@
 
 namespace dxtc_tool {
 
-
-
-
 // C-like function wrappers
+bool isDXTC(GLenum pixelFormat);
+
 bool VerticalFlip(size_t Width, size_t Height, GLenum Format, void * pPixels);
 
 bool CompressedImageTranslucent(size_t Width, size_t Height, GLenum Format, void * pPixels);
@@ -141,6 +140,20 @@ protected:
 // C-Like Function Wrappers
 //////////////////////////////////////////////////////////////////////
 
+inline bool isDXTC(GLenum pixelFormat)
+{
+    switch(pixelFormat)
+    {
+        case(GL_COMPRESSED_RGB_S3TC_DXT1_EXT):
+        case(GL_COMPRESSED_RGBA_S3TC_DXT1_EXT):
+        case(GL_COMPRESSED_RGBA_S3TC_DXT3_EXT):
+        case(GL_COMPRESSED_RGBA_S3TC_DXT5_EXT):
+            return true;
+        default:
+            return false;
+    }
+}
+
 inline bool VerticalFlip(size_t Width, size_t Height, GLenum Format, void * pPixels) {
     return (dxtc_pixels(Width, Height, Format, pPixels)).VFlip(); 
 }