From 8dbabc8b434c3a99743c91055402aa9d5c5d02ba Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Tue, 7 Apr 2020 12:12:52 +0100
Subject: [PATCH] Texture-compression fixes

Rename a highly confusing method, and disable the older texture-
compression code since it interacts badly with the new texture-cache.
---
 simgear/scene/material/TextureBuilder.cxx |  4 ++--
 simgear/scene/model/ModelRegistry.cxx     | 13 ++++++++++---
 simgear/scene/model/model.cxx             |  4 ++--
 simgear/scene/util/SGSceneFeatures.cxx    |  8 +++++++-
 simgear/scene/util/SGSceneFeatures.hxx    |  2 +-
 5 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/simgear/scene/material/TextureBuilder.cxx b/simgear/scene/material/TextureBuilder.cxx
index 6fff6348..dd228fd4 100644
--- a/simgear/scene/material/TextureBuilder.cxx
+++ b/simgear/scene/material/TextureBuilder.cxx
@@ -292,9 +292,9 @@ bool setAttrs(const TexTuple& attrs, Texture* tex,
         int s = image->s();
         int t = image->t();
         if (s <= t && 32 <= s) {
-            SGSceneFeatures::instance()->setTextureCompression(tex);
+            SGSceneFeatures::instance()->applyTextureCompression(tex);
         } else if (t < s && 32 <= t) {
-            SGSceneFeatures::instance()->setTextureCompression(tex);
+            SGSceneFeatures::instance()->applyTextureCompression(tex);
         }
         tex->setMaxAnisotropy(SGSceneFeatures::instance()->getTextureFilter());
     } else {
diff --git a/simgear/scene/model/ModelRegistry.cxx b/simgear/scene/model/ModelRegistry.cxx
index 3178d206..5e2bcdf4 100644
--- a/simgear/scene/model/ModelRegistry.cxx
+++ b/simgear/scene/model/ModelRegistry.cxx
@@ -117,7 +117,9 @@ protected:
     }
 };
 
-
+// disabling old-syle texture compression in favour of the 
+// texture-cache
+#if 0
 class SGTexCompressionVisitor : public SGTextureStateAttributeVisitor {
 public:
   virtual void apply(int, StateSet::RefAttributePair& refAttr)
@@ -142,12 +144,13 @@ public:
     int t = image->t();
 
     if (s <= t && 32 <= s) {
-      SGSceneFeatures::instance()->setTextureCompression(texture);
+      SGSceneFeatures::instance()->applyTextureCompression(texture);
     } else if (t < s && 32 <= t) {
-      SGSceneFeatures::instance()->setTextureCompression(texture);
+      SGSceneFeatures::instance()->applyTextureCompression(texture);
     }
   }
 };
+#endif
 
 class SGTexDataVarianceVisitor : public SGTextureStateAttributeVisitor {
 public:
@@ -645,8 +648,12 @@ osg::Node* OptimizeModelPolicy::optimize(osg::Node* node,
     SGTexDataVarianceVisitor dataVarianceVisitor;
     node->accept(dataVarianceVisitor);
 
+// disabling old-syle texture compression in favour of the 
+// texture-cache
+#if 0
     SGTexCompressionVisitor texComp;
     node->accept(texComp);
+#endif
     return node;
 }
 
diff --git a/simgear/scene/model/model.cxx b/simgear/scene/model/model.cxx
index 3eea102f..008fdeb5 100644
--- a/simgear/scene/model/model.cxx
+++ b/simgear/scene/model/model.cxx
@@ -75,9 +75,9 @@ SGLoadTexture2D(bool staticTexture, const std::string& path,
     int t = image->t();
 
     if (s <= t && 32 <= s) {
-      SGSceneFeatures::instance()->setTextureCompression(texture.get());
+      SGSceneFeatures::instance()->applyTextureCompression(texture.get());
     } else if (t < s && 32 <= t) {
-      SGSceneFeatures::instance()->setTextureCompression(texture.get());
+      SGSceneFeatures::instance()->applyTextureCompression(texture.get());
     }
   }
 
diff --git a/simgear/scene/util/SGSceneFeatures.cxx b/simgear/scene/util/SGSceneFeatures.cxx
index f17b52ac..f04ff858 100644
--- a/simgear/scene/util/SGSceneFeatures.cxx
+++ b/simgear/scene/util/SGSceneFeatures.cxx
@@ -67,8 +67,13 @@ SGSceneFeatures::instance()
 }
 
 void
-SGSceneFeatures::setTextureCompression(osg::Texture* texture) const
+SGSceneFeatures::applyTextureCompression(osg::Texture* texture) const
 {
+  // disable older texture-compression, since it interacts confusingly
+  // with the the runtime texture-cache. We always want to use 
+  // 'USE_IMAGE_DATA_FORMAT' when the texture-cache is active, since we
+  // decided whether to compress (or not) prior to this point.
+#if 0
   switch (_textureCompression) {
   case UseARBCompression:
     texture->setInternalFormatMode(osg::Texture::USE_ARB_COMPRESSION);
@@ -86,6 +91,7 @@ SGSceneFeatures::setTextureCompression(osg::Texture* texture) const
     texture->setInternalFormatMode(osg::Texture::USE_IMAGE_DATA_FORMAT);
     break;
   }
+#endif
 }
 
 bool
diff --git a/simgear/scene/util/SGSceneFeatures.hxx b/simgear/scene/util/SGSceneFeatures.hxx
index cb9453d5..9be4e99a 100644
--- a/simgear/scene/util/SGSceneFeatures.hxx
+++ b/simgear/scene/util/SGSceneFeatures.hxx
@@ -58,7 +58,7 @@ public:
     TextureCompression getTextureCompression() const { return _textureCompression; }
 
     // modify the texture compression on the texture parameter
-    void setTextureCompression(osg::Texture* texture) const;
+    void applyTextureCompression(osg::Texture* texture) const;
 
     void setEnablePointSpriteLights(bool enable)
     {