Added new osg::TexEnvCombine state attribute.

src/osg/Makefile

@@ -71,6 +71,7 @@ CXXFILES =\
 	Stencil.cpp\
 	Switch.cpp\
 	TexEnv.cpp\
+	TexEnvCombine.cpp\
 	TexGen.cpp\
 	TexMat.cpp\
 	Texture.cpp\

src/osg/TexEnvCombine.cpp

@@ -0,0 +1,55 @@
+#include <osg/TexEnvCombine>
+#include <osg/GLExtensions>
+
+using namespace osg;
+
+TexEnvCombine::TexEnvCombine()
+{
+    _constantColor.set(0.0f,0.0f,0.0f,0.0f);
+}
+
+
+TexEnvCombine::~TexEnvCombine()
+{
+}
+
+void TexEnvCombine::apply(State&) const
+{
+    static bool isTexEnvCombineSupported =
+        isGLExtensionSupported("GL_ARB_texture_env_combine");
+
+    if (isTexEnvCombineSupported)
+    {
+        glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
+
+        glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, _combine_RGB);
+        glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, _combine_Alpha);
+
+        glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB,_source0_RGB );
+        glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, _source1_RGB);
+        glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB,_source2_RGB );
+
+        glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, _source0_Alpha);
+        glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_ALPHA_ARB, _source1_Alpha);
+        glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE2_ALPHA_ARB, _source2_Alpha);
+
+        glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, _operand0_RGB);
+        glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, _operand1_RGB);
+        glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, _operand2_RGB);
+
+        glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_ALPHA_ARB, _operand0_Alpha);
+        glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_ALPHA_ARB, _operand1_Alpha);
+        glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND2_ALPHA_ARB, _operand2_Alpha);
+
+        glTexEnvf( GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, _scale_RGB);
+        glTexEnvf( GL_TEXTURE_ENV, GL_ALPHA_SCALE, _scale_Alpha);
+
+        glTexEnvfv( GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, _constantColor.ptr());
+    }
+    else
+    {
+        // what is the best fallback when the tex env combine is not supported??
+        // we will resort the settung the OpenGL default of GL_MODULATE.
+        glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+    }
+}