From 70cdc3e3af90714537bc4b5c9fce64939623b2bd Mon Sep 17 00:00:00 2001
From: gwaldron <gwaldron@gmail.com>
Date: Mon, 12 Nov 2018 12:54:39 -0500
Subject: [PATCH] Fix a bug in which the rex elevation texture was not getting
 applied for subsequent layers

---
 .../engine_rex/DrawTileCommand.cpp            |  6 ++--
 .../engine_rex/LayerDrawable.cpp              | 34 +++++++++++++++++++
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/src/osgEarthDrivers/engine_rex/DrawTileCommand.cpp b/src/osgEarthDrivers/engine_rex/DrawTileCommand.cpp
index 9ae683810a..1130686eef 100644
--- a/src/osgEarthDrivers/engine_rex/DrawTileCommand.cpp
+++ b/src/osgEarthDrivers/engine_rex/DrawTileCommand.cpp
@@ -78,7 +78,8 @@ DrawTileCommand::draw(osg::RenderInfo& ri, DrawState& dsMaster, osg::Referenced*
 
             if (sampler._texture.valid() && !samplerState._texture.isSetTo(sampler._texture.get()))
             {
-                state.applyTextureAttribute((*dsMaster._bindings)[s].unit(), sampler._texture.get());
+                state.setActiveTextureUnit((*dsMaster._bindings)[s].unit());
+                sampler._texture->apply(state);
                 samplerState._texture = sampler._texture.get();
             }
 
@@ -109,7 +110,8 @@ DrawTileCommand::draw(osg::RenderInfo& ri, DrawState& dsMaster, osg::Referenced*
 
             if (sampler._texture.valid() && !samplerState._texture.isSetTo(sampler._texture.get()))
             {
-                state.applyTextureAttribute((*dsMaster._bindings)[s].unit(), sampler._texture.get());
+                state.setActiveTextureUnit((*dsMaster._bindings)[s].unit());
+                sampler._texture->apply(state);
                 samplerState._texture = sampler._texture.get();
             }
 
diff --git a/src/osgEarthDrivers/engine_rex/LayerDrawable.cpp b/src/osgEarthDrivers/engine_rex/LayerDrawable.cpp
index a9f3e8fa35..c9c914634f 100644
--- a/src/osgEarthDrivers/engine_rex/LayerDrawable.cpp
+++ b/src/osgEarthDrivers/engine_rex/LayerDrawable.cpp
@@ -47,6 +47,35 @@ LayerDrawable::~LayerDrawable()
     setStateSet(0L);
 }
 
+namespace
+{
+    // Hack State so we can dirty the texture attrs without dirtying the other 
+    // attributes (as dirtyAllAttributes() would do.
+    struct StateEx : public osg::State
+    {
+        void dirtyAllTextureAttributes()
+        {
+            // dirtyAllTextureAttributes. (Don't call state->dirtyAllAttributes because that
+            // will mess up positional state attributes like light sources)
+            for (TextureAttributeMapList::iterator tamItr = _textureAttributeMapList.begin();
+                tamItr != _textureAttributeMapList.end();
+                ++tamItr)
+            {
+                osg::State::AttributeMap& attributeMap = *tamItr;
+                for (osg::State::AttributeMap::iterator aitr = attributeMap.begin();
+                    aitr != attributeMap.end();
+                    ++aitr)
+                {
+                    osg::State::AttributeStack& as = aitr->second;
+                    as.last_applied_attribute = 0;
+                    as.changed = true;
+                }
+            }
+        }
+    };
+}
+
+
 void
 LayerDrawable::drawImplementation(osg::RenderInfo& ri) const
 {
@@ -76,6 +105,11 @@ LayerDrawable::drawImplementation(osg::RenderInfo& ri) const
     // necessary when doing custom OpenGL within a Drawable.
     if (_clearOsgState)
     {
+        // Dirty the texture attributes so OSG can properly reset them
+        // NOTE: cannot call state.dirtyAllAttributes, because that would invalidate
+        // positional state like light sources!
+        reinterpret_cast<StateEx*>(ri.getState())->dirtyAllTextureAttributes();
+
         // NOTE: this is a NOOP in OSG 3.5.x, but not in 3.4.x ... Later we will need to
         // revisit whether to call disableAllVertexArrays() in 3.5.x instead.
         ri.getState()->dirtyAllVertexArrays();