From 5fbdb64bb913717a81ccbf919dea2789b227df74 Mon Sep 17 00:00:00 2001
From: scrawl <720642+scrawl@users.noreply.github.com>
Date: Sat, 14 Oct 2017 18:28:46 +0000
Subject: [PATCH] Add OPENMW_DECOMPRESS_TEXTURES environment variable to
 decompress textures in software if not supported by graphics hardware

Disabled by default due to requiring new functionality that was just added to OSG 3.6 or OpenMW/OSG.
---
 components/resource/imagemanager.cpp | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/components/resource/imagemanager.cpp b/components/resource/imagemanager.cpp
index 441fd8212..000a833cf 100644
--- a/components/resource/imagemanager.cpp
+++ b/components/resource/imagemanager.cpp
@@ -69,7 +69,6 @@ namespace Resource
                         // This one works too. Should it be included in isTextureCompressionS3TCSupported()? Submitted as a patch to OSG.
                         && !osg::isGLExtensionSupported(0, "GL_S3_s3tc"))
                 {
-                    std::cerr << "Error loading " << filename << ": no S3TC texture compression support installed" << std::endl;
                     return false;
                 }
                 break;
@@ -123,12 +122,31 @@ namespace Resource
                 return mWarningImage;
             }
 
-            osg::Image* image = result.getImage();
+            osg::ref_ptr<osg::Image> image = result.getImage();
+
             image->setFileName(normalized);
             if (!checkSupported(image, filename))
             {
-                mCache->addEntryToObjectCache(normalized, mWarningImage);
-                return mWarningImage;
+                static bool uncompress = (getenv("OPENMW_DECOMPRESS_TEXTURES") != 0);
+                if (!uncompress)
+                {
+                    std::cerr << "Error loading " << filename << ": no S3TC texture compression support installed" << std::endl;
+                    mCache->addEntryToObjectCache(normalized, mWarningImage);
+                    return mWarningImage;
+                }
+                else
+                {
+                    // decompress texture in software if not supported by GPU
+                    // requires update to getColor() to be released with OSG 3.6
+                    osg::ref_ptr<osg::Image> newImage = new osg::Image;
+                    newImage->setFileName(image->getFileName());
+                    newImage->allocateImage(image->s(), image->t(), image->r(), image->isImageTranslucent() ? GL_RGBA : GL_RGB, GL_UNSIGNED_BYTE);
+                    for (int s=0; s<image->s(); ++s)
+                        for (int t=0; t<image->t(); ++t)
+                            for (int r=0; r<image->r(); ++r)
+                                newImage->setColor(image->getColor(s,t,r), s,t,r);
+                    image = newImage;
+                }
             }
 
             mCache->addEntryToObjectCache(normalized, image);