Added osgpbuffer example source.

examples/osgpbuffer/RenderToTextureStage.cpp

@@ -0,0 +1,80 @@
+#include <cassert>
+//#include <osgDB/ReadFile>
+
+#include "RenderToTextureStage.h"
+
+//using namespace osg;
+//using namespace osgUtil;
+
+// register a RenderToTextureStage prototype with the RenderBin prototype list.
+//RegisterRenderBinProxy<RenderToTextureStage> s_registerRenderToTextureStageProxy;
+
+MyRenderToTextureStage::MyRenderToTextureStage()
+{
+    _pbuffer = 0L;
+}
+
+MyRenderToTextureStage::~MyRenderToTextureStage()
+{
+}
+
+void MyRenderToTextureStage::reset()
+{
+    RenderStage::reset();
+}
+
+void MyRenderToTextureStage::draw(osg::State& state, osgUtil::RenderLeaf*& previous)
+{
+    if (_pbuffer && _texture.valid())
+    {
+        // Create pbuffer texture
+        const unsigned int contextID = state.getContextID();
+        GLuint& handle = _texture->getTextureObject(contextID);
+        if (handle == 0)
+        {
+            // Create dynamic texture, subload callback required.
+            _texture->apply(state);
+        }
+    
+        HDC hdc = ::wglGetCurrentDC();
+        HGLRC hglrc = ::wglGetCurrentContext();
+
+        // Release pbuffer from "render to texture".
+        _pbuffer->releaseTexImage();
+
+        // Make the p-buffer's context current.
+        _pbuffer->makeCurrent();
+
+        // Render in p-buffer.
+        RenderStage::draw(state,previous);
+
+        // restore window's context as current.
+        if (!::wglMakeCurrent(hdc, hglrc))
+        {
+            assert(0);
+        }
+
+        if (true /*_isRenderTextureSupported*/)
+        {
+            // transfer contents of p-buffer to texture
+            _pbuffer->bindTexImage(handle);
+        }
+        else
+        {
+// TODO:
+//          _pbuffer->copyTexImage(state);
+        }
+
+    }
+    else
+    {
+        RenderStage::draw(state,previous);
+
+        // now copy the rendered image to attached texture.
+        if (_texture.valid())
+            _texture->copyTexImage2D(state,_viewport->x(),_viewport->y(),_viewport->width(),_viewport->height());
+    
+        if (_image.valid())
+            _image->readPixels(_viewport->x(),_viewport->y(),_viewport->width(),_viewport->height(),GL_RGBA,GL_UNSIGNED_BYTE);
+    }
+}