From a742cb682e882608c5bff1569d5125ce425a2d8f Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Tue, 1 Nov 2005 10:42:54 +0000
Subject: [PATCH] Added RenderTargetFallback option into osg::CameraNode.

---
 include/osg/CameraNode      |  8 +++++++-
 src/osg/CameraNode.cpp      | 28 +++++++++++++++++++++++++---
 src/osgSim/Impostor.cpp     |  2 +-
 src/osgUtil/RenderStage.cpp | 33 +++++++++++++++++++++------------
 4 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/include/osg/CameraNode b/include/osg/CameraNode
index 7b0d6589f..e9b14a4f2 100644
--- a/include/osg/CameraNode
+++ b/include/osg/CameraNode
@@ -191,9 +191,14 @@ class OSG_EXPORT CameraNode : public Transform, public CullSettings
             SEPERATE_WINDOW
         };
 
-        void setRenderTargetImplementation(RenderTargetImplementation impl) { _renderTargetImplementation = impl; }
+        void setRenderTargetImplementation(RenderTargetImplementation impl);
+
+        void setRenderTargetImplementation(RenderTargetImplementation impl, RenderTargetImplementation fallback);
+
         RenderTargetImplementation getRenderTargetImplementation() const { return _renderTargetImplementation; }
 
+        RenderTargetImplementation getRenderTargetFallback() const { return _renderTargetFallback; }
+
 
         /** Set the draw buffer used at the start of each frame draw. 
           * Note, a buffer value of GL_NONE is used to sepecify that the rendering back-end should choose the most appropriate buffer.*/
@@ -342,6 +347,7 @@ class OSG_EXPORT CameraNode : public Transform, public CullSettings
         RenderBufferList            _renderBufferList;
         
         RenderTargetImplementation  _renderTargetImplementation;
+        RenderTargetImplementation  _renderTargetFallback;
         BufferAttachmentMap         _bufferAttachmentMap;
 
         ref_ptr<GraphicsContext>    _graphicsContext;
diff --git a/src/osg/CameraNode.cpp b/src/osg/CameraNode.cpp
index 4e051559e..47f156ad1 100644
--- a/src/osg/CameraNode.cpp
+++ b/src/osg/CameraNode.cpp
@@ -11,11 +11,10 @@
  * OpenSceneGraph Public License for more details.
 */
 #include <osg/CameraNode>
+#include <osg/Notify>
 
 using namespace osg;
 
-
-
 CameraNode::CameraNode():
     _clearColor(osg::Vec4(0.0f,0.0f,0.0f,1.0f)),
     _clearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT),
@@ -23,7 +22,8 @@ CameraNode::CameraNode():
     _renderOrder(POST_RENDER),
     _drawBuffer(GL_NONE),
     _readBuffer(GL_NONE),
-    _renderTargetImplementation(FRAME_BUFFER)
+    _renderTargetImplementation(FRAME_BUFFER),
+    _renderTargetFallback(FRAME_BUFFER)
 {
     setStateSet(new StateSet);
 }
@@ -42,6 +42,7 @@ CameraNode::CameraNode(const CameraNode& camera,const CopyOp& copyop):
     _drawBuffer(camera._drawBuffer),
     _readBuffer(camera._readBuffer),
     _renderTargetImplementation(camera._renderTargetImplementation),
+    _renderTargetFallback(camera._renderTargetFallback),
     _bufferAttachmentMap(camera._bufferAttachmentMap),
     _postDrawCallback(camera._postDrawCallback)
 {
@@ -52,6 +53,27 @@ CameraNode::~CameraNode()
 {
 }
 
+void CameraNode::setRenderTargetImplementation(RenderTargetImplementation impl)
+{
+    _renderTargetImplementation = impl;
+    if (impl<FRAME_BUFFER) _renderTargetFallback = (RenderTargetImplementation)(impl+1);
+    else _renderTargetFallback = impl;
+}   
+
+void CameraNode::setRenderTargetImplementation(RenderTargetImplementation impl, RenderTargetImplementation fallback)
+{
+    if (impl<fallback)
+    {
+        _renderTargetImplementation = impl;
+        _renderTargetFallback = fallback;
+    }
+    else
+    {
+        osg::notify(osg::NOTICE)<<"Warning: CameraNode::setRenderTargetImplementation(impl,fallback) must have a lower rated fallback than the main target implementation."<<std::endl;
+        setRenderTargetImplementation(impl);
+    }
+}
+
 void CameraNode::setColorMask(osg::ColorMask* colorMask)
 {
     if (_colorMask == colorMask) return;
diff --git a/src/osgSim/Impostor.cpp b/src/osgSim/Impostor.cpp
index 708c80544..5a8f29629 100644
--- a/src/osgSim/Impostor.cpp
+++ b/src/osgSim/Impostor.cpp
@@ -456,7 +456,7 @@ ImpostorSprite* Impostor::createImpostorSprite(osgUtil::CullVisitor* cv)
     camera->setViewport(0,0,new_s,new_t);
 
     // tell the camera to use OpenGL frame buffer object where supported.
-    camera->setRenderTargetImplementation(osg::CameraNode::FRAME_BUFFER_OBJECT);
+    camera->setRenderTargetImplementation(osg::CameraNode::FRAME_BUFFER_OBJECT, osg::CameraNode::FRAME_BUFFER);
 
     // set the camera to render before the main camera.
     camera->setRenderOrder(osg::CameraNode::PRE_RENDER);
diff --git a/src/osgUtil/RenderStage.cpp b/src/osgUtil/RenderStage.cpp
index d16324a3c..a0e043c00 100644
--- a/src/osgUtil/RenderStage.cpp
+++ b/src/osgUtil/RenderStage.cpp
@@ -18,6 +18,7 @@
 #include <osg/Texture3D>
 #include <osg/TextureRectangle>
 #include <osg/TextureCubeMap>
+#include <osg/GLExtensions>
 
 #include <osgUtil/Statistics>
 
@@ -151,6 +152,7 @@ void RenderStage::runCameraSetUp(osg::State& state)
     if (!_camera) return;
     
     osg::CameraNode::RenderTargetImplementation renderTargetImplemntation = _camera->getRenderTargetImplementation();
+    osg::CameraNode::RenderTargetImplementation renderTargetFallback = _camera->getRenderTargetFallback();
 
     osg::CameraNode::BufferAttachmentMap& bufferAttachements = _camera->getBufferAttachmentMap();
 
@@ -170,19 +172,15 @@ void RenderStage::runCameraSetUp(osg::State& state)
 
         if (!fbo_supported)
         {
-            // fallback to using pbuffer
-            #ifdef _WIN32    
-                // Only Win32 currently support PBuffer RTT.
-                osg::notify(osg::INFO)<<"RenderStage::runCameraSetUp(State&): Using fallback to PIXEL_BUFFER_RTT"<<std::endl;
+            if (renderTargetImplemntation<renderTargetFallback)
+                renderTargetImplemntation = renderTargetFallback;
+            else
                 renderTargetImplemntation = osg::CameraNode::PIXEL_BUFFER_RTT;
-            #else
-                osg::notify(osg::INFO)<<"RenderStage::runCameraSetUp(State&): Using fallback to PIXEL_BUFFER"<<std::endl;
-                renderTargetImplemntation = osg::CameraNode::PIXEL_BUFFER;
-            #endif
-
         }
         else if (!_fbo)
         {
+            osg::notify(osg::INFO)<<"Setting up osg::CameraNode::FRAME_BUFFER_OBJECT"<<std::endl;
+
             _fbo = new osg::FrameBufferObject;
 
             setDrawBuffer(GL_BACK);
@@ -234,6 +232,15 @@ void RenderStage::runCameraSetUp(osg::State& state)
         }
     }
     
+    // check whether PBuffer-RTT is supported or not
+    if (renderTargetImplemntation==osg::CameraNode::PIXEL_BUFFER_RTT && 
+        !osg::isGLExtensionSupported(state.getContextID(), "ARB_render_texture"))
+    {    
+        if (renderTargetImplemntation<renderTargetFallback)
+            renderTargetImplemntation = renderTargetFallback;
+        else
+            renderTargetImplemntation = osg::CameraNode::PIXEL_BUFFER;
+    }
 
     // if any of the renderTargetImplementations require a seperate graphics context such as with pbuffer try in turn to
     // set up, but if each level fails then resort to the next level down.    
@@ -390,12 +397,14 @@ void RenderStage::runCameraSetUp(osg::State& state)
                 if (renderTargetImplemntation==osg::CameraNode::PIXEL_BUFFER_RTT)
                 {
                     // fallback to using standard PBuffer, this will allow this while loop to continue
-                    renderTargetImplemntation=osg::CameraNode::PIXEL_BUFFER;
+                    if (renderTargetImplemntation<renderTargetFallback)
+                        renderTargetImplemntation = renderTargetFallback;
+                    else
+                        renderTargetImplemntation = osg::CameraNode::PIXEL_BUFFER;
                 }
                 else 
                 {
-                    // fallback to using the frame buffer, this while loop will now exit.
-                    renderTargetImplemntation=osg::CameraNode::FRAME_BUFFER;
+                    renderTargetImplemntation = osg::CameraNode::FRAME_BUFFER;
                 }
             }