Martin Spindler, new osg::ClampColor state attribute.

src/osg/ClampColor.cpp

@@ -0,0 +1,111 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2005 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+#include <osg/ClampColor>
+#include <osg/GLExtensions>
+#include <osg/State>
+#include <osg/Notify>
+#include <osg/buffered_value>
+
+
+using namespace osg;
+
+ClampColor::ClampColor():
+   _target(CLAMP_FRAGMENT_COLOR),
+   _mode(FIXED_ONLY)
+{
+}
+
+ClampColor::ClampColor(Target target, Mode mode):
+   _target(target),
+   _mode(mode)
+{
+}
+
+ClampColor::~ClampColor()
+{
+}
+
+void ClampColor::apply(State& state) const
+{
+
+   // get the contextID (user defined ID of 0 upwards) for the 
+    // current OpenGL context.
+    const unsigned int contextID = state.getContextID();
+    
+    const Extensions* extensions = getExtensions(contextID,true);
+                                        
+    if (!extensions->isClampColorSupported())
+    {
+        notify(WARN)<<"Warning: ClampColor::apply(..) failed, ClampColor is not support by OpenGL driver."<<std::endl;
+        return;
+    }
+
+    extensions->glClampColor(static_cast<GLenum>(_target), static_cast<GLenum>(_mode));
+}
+
+
+typedef buffered_value< ref_ptr<ClampColor::Extensions> > BufferedExtensions;
+static BufferedExtensions s_extensions;
+
+ClampColor::Extensions* ClampColor::getExtensions(unsigned int contextID,bool createIfNotInitalized)
+{
+    if (!s_extensions[contextID] && createIfNotInitalized) s_extensions[contextID] = new Extensions(contextID);
+    return s_extensions[contextID].get();
+}
+
+void ClampColor::setExtensions(unsigned int contextID,Extensions* extensions)
+{
+    s_extensions[contextID] = extensions;
+}
+
+
+ClampColor::Extensions::Extensions(unsigned int contextID)
+{
+    setupGLExtenions(contextID);
+}
+
+ClampColor::Extensions::Extensions(const Extensions& rhs):
+    Referenced()
+{
+    _isClampColorSupported = rhs._isClampColorSupported;
+    _glClampColor = rhs._glClampColor;
+}
+
+void ClampColor::Extensions::lowestCommonDenominator(const Extensions& rhs)
+{
+    if (!rhs._isClampColorSupported) _isClampColorSupported = false;
+    if (!rhs._glClampColor)          _glClampColor = 0;
+}
+
+void ClampColor::Extensions::setupGLExtenions(unsigned int contextID)
+{
+    _isClampColorSupported = isGLExtensionSupported(contextID,"GL_ARB_color_buffer_float") ||
+                             strncmp((const char*)glGetString(GL_VERSION),"2.0",3)>=0;
+
+    _glClampColor = getGLExtensionFuncPtr("glClampColor", "glClampColorARB");
+}
+
+void ClampColor::Extensions::glClampColor(GLenum target, GLenum mode) const
+{
+    if (_glClampColor)
+    {
+        typedef void (APIENTRY * GLClampColorProc) (GLenum target, GLenum mode);
+        ((GLClampColorProc)_glClampColor)(target,mode);
+    }
+    else
+    {
+        notify(WARN)<<"Error: glClampColor not supported by OpenGL driver"<<std::endl;
+    }
+}
+
+

src/osg/GNUmakefile

@@ -20,6 +20,7 @@ CXXFILES =\
 	ClearNode.cpp\
 	ClipNode.cpp\
 	ClipPlane.cpp\
+	ClampColor.cpp\
 	ClusterCullingCallback.cpp\
 	CollectOccludersVisitor.cpp\
 	ColorMask.cpp\