Added support for the tex_env_add and tex_env_crossbar extensions.

include/osg/TexEnv

@@ -47,7 +47,8 @@ class SG_EXPORT TexEnv : public StateAttribute
             DECAL     = GL_DECAL,
             MODULATE  = GL_MODULATE,
             BLEND     = GL_BLEND,
-            REPLACE   = GL_REPLACE
+            REPLACE   = GL_REPLACE,
+            ADD       = GL_ADD
         };
 
         void setMode( const Mode mode ) { _mode = mode; }

include/osg/TexEnvCombine

@@ -37,6 +37,10 @@
 #define GL_PREVIOUS_ARB                                    0x8578
 #endif
 
+#ifndef GL_TEXTURE0
+#define GL_TEXTURE0 0x84C0
+#endif
+
 namespace osg {
 
 /** TexEnvCombine - encapsulates the OpenGL glTexEnvCombine (texture environment) state.*/
@@ -49,6 +53,7 @@ class SG_EXPORT TexEnvCombine : public StateAttribute
         /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
         TexEnvCombine(const TexEnvCombine& texenv,const CopyOp& copyop=CopyOp::SHALLOW_COPY):
             StateAttribute(texenv,copyop),
+            _needsTexEnvCrossbar(texenv._needsTexEnvCrossbar),
             _combine_RGB(texenv._combine_RGB),
             _combine_Alpha(texenv._combine_Alpha),
             _source0_RGB(texenv._source0_RGB),
@@ -81,6 +86,7 @@ class SG_EXPORT TexEnvCombine : public StateAttribute
             COMPARE_StateAttribute_Types(TexEnvCombine,sa)
 
             // compare each paramter in turn against the rhs.
+            COMPARE_StateAttribute_Parameter(_needsTexEnvCrossbar)
             COMPARE_StateAttribute_Parameter(_combine_RGB)
             COMPARE_StateAttribute_Parameter(_combine_Alpha)
             COMPARE_StateAttribute_Parameter(_source0_RGB)
@@ -121,19 +127,27 @@ class SG_EXPORT TexEnvCombine : public StateAttribute
         
         enum SourceParam
         {
-            TEXTURE         = GL_TEXTURE,
             CONSTANT        = GL_CONSTANT_ARB,
             PRIMARY_COLOR   = GL_PRIMARY_COLOR_ARB,
-            PREVIOUS        = GL_PREVIOUS_ARB
+            PREVIOUS        = GL_PREVIOUS_ARB,
+            TEXTURE         = GL_TEXTURE,
+            TEXTURE_0       = GL_TEXTURE0,
+            TEXTURE_1       = GL_TEXTURE0+1,
+            TEXTURE_2       = GL_TEXTURE0+2,
+            TEXTURE_3       = GL_TEXTURE0+3,
+            TEXTURE_4       = GL_TEXTURE0+4,
+            TEXTURE_5       = GL_TEXTURE0+5,
+            TEXTURE_6       = GL_TEXTURE0+6,
+            TEXTURE_7       = GL_TEXTURE0+7
         };
         
-        void setSource0_RGB(GLint sp) { _source0_RGB = sp; }
+        void setSource0_RGB(GLint sp) { _source0_RGB = sp; computeNeedoForTexEnvCombiners(); }
-        void setSource1_RGB(GLint sp) { _source1_RGB = sp; }
+        void setSource1_RGB(GLint sp) { _source1_RGB = sp; computeNeedoForTexEnvCombiners(); }
-        void setSource2_RGB(GLint sp) { _source2_RGB = sp; }
+        void setSource2_RGB(GLint sp) { _source2_RGB = sp; computeNeedoForTexEnvCombiners(); }
         
-        void setSource0_Alpha(GLint sp) { _source0_Alpha = sp; }
+        void setSource0_Alpha(GLint sp) { _source0_Alpha = sp; computeNeedoForTexEnvCombiners(); }
-        void setSource1_Alpha(GLint sp) { _source1_Alpha = sp; }
+        void setSource1_Alpha(GLint sp) { _source1_Alpha = sp; computeNeedoForTexEnvCombiners(); }
-        void setSource2_Alpha(GLint sp) { _source2_Alpha = sp; }
+        void setSource2_Alpha(GLint sp) { _source2_Alpha = sp; computeNeedoForTexEnvCombiners(); }
 
         GLint getSource0_RGB() const { return _source0_RGB; }
         GLint getSource1_RGB() const { return _source1_RGB; }
@@ -184,11 +198,38 @@ class SG_EXPORT TexEnvCombine : public StateAttribute
 
         virtual ~TexEnvCombine();
 
+        inline bool needsTexEnvCombiner(GLint value) const
+        {
+            switch(value)
+            {
+                case(CONSTANT):
+                case(PRIMARY_COLOR):
+                case(PREVIOUS):
+                case(TEXTURE):
+                    return false;
+            }
+            return true;
+        }
+
+        void computeNeedoForTexEnvCombiners()
+        {
+            _needsTexEnvCrossbar = (needsTexEnvCombiner(_source0_RGB) ||
+                                    needsTexEnvCombiner(_source1_RGB) ||
+                                    needsTexEnvCombiner(_source2_RGB) ||
+                                    needsTexEnvCombiner(_source0_Alpha) ||
+                                    needsTexEnvCombiner(_source1_Alpha) ||
+                                    needsTexEnvCombiner(_source2_Alpha)); 
+        }
+        
+
+        
+
+
+        bool            _needsTexEnvCrossbar;
 
         GLint           _combine_RGB;
         GLint           _combine_Alpha;
     
-
         GLint           _source0_RGB;
         GLint           _source1_RGB;
         GLint           _source2_RGB;

src/osg/TexEnv.cpp

@@ -1,4 +1,5 @@
 #include <osg/TexEnv>
+#include <osg/GLExtensions>
 
 using namespace osg;
 
@@ -14,6 +15,16 @@ TexEnv::~TexEnv()
 }
 
 void TexEnv::apply(State&) const
+{
+    if (_mode==ADD)
+    {
+        static bool isTexEnvAddSupported = isGLExtensionSupported("GL_ARB_texture_env_add");
+        if (isTexEnvAddSupported)
+            glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, ADD);
+        else // fallback on OpenGL default.
+            glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, MODULATE);
+    }
+    else
     {
         glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, _mode);
         if (_mode==TexEnv::BLEND)
@@ -21,3 +32,4 @@ void TexEnv::apply(State&) const
             glTexEnvfv( GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, _color.ptr());
         }
     }
+}

src/osg/TexEnvCombine.cpp

@@ -4,6 +4,7 @@
 using namespace osg;
 
 TexEnvCombine::TexEnvCombine():
+            _needsTexEnvCrossbar(false),
             _combine_RGB(GL_MODULATE),
             _combine_Alpha(GL_MODULATE),
             _source0_RGB(GL_TEXTURE),
@@ -33,7 +34,10 @@ void TexEnvCombine::apply(State&) const
     static bool isTexEnvCombineSupported =
         isGLExtensionSupported("GL_ARB_texture_env_combine");
 
-    if (isTexEnvCombineSupported)
+    static bool isTexEnvCrossbarSupported =
+        isGLExtensionSupported("GL_ARB_texture_env_crossbar");
+
+    if (isTexEnvCrossbarSupported || (!_needsTexEnvCrossbar && isTexEnvCombineSupported))
     {
         glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
 

src/osgPlugins/osg/TexEnv.cpp

@@ -66,6 +66,7 @@ bool TexEnv_writeLocalData(const Object& obj, Output& fw)
         case(TexEnv::DECAL):
         case(TexEnv::MODULATE):
         case(TexEnv::REPLACE):
+        case(TexEnv::ADD):
             break;
         case(TexEnv::BLEND):
         default:
@@ -82,6 +83,7 @@ bool TexEnv_matchModeStr(const char* str,TexEnv::Mode& mode)
     else if (strcmp(str,"MODULATE")==0) mode = TexEnv::MODULATE;
     else if (strcmp(str,"BLEND")==0)    mode = TexEnv::BLEND;
     else if (strcmp(str,"REPLACE")==0)  mode = TexEnv::REPLACE;
+    else if (strcmp(str,"ADD")==0)      mode = TexEnv::ADD;
     else return false;
     return true;
 }
@@ -95,6 +97,7 @@ const char* TexEnv_getModeStr(TexEnv::Mode mode)
         case(TexEnv::MODULATE): return "MODULATE";
         case(TexEnv::BLEND):    return "BLEND";
         case(TexEnv::REPLACE):  return "REPLACE";
+        case(TexEnv::ADD):      return "ADD";
     }
     return "";
 }