Changeset 7690 for OpenSceneGraph/trunk/src/osgShadow/ShadowMap.cpp

Timestamp:

12/15/07 16:17:51 (5 years ago)

Author:

robert

Message:

Tweaked the abmient lighting contribution so that the OpenGL vertex lighting has
the ambient light source switched off, and use the fragment shader to add this
contribution back in.

Files:

• OpenSceneGraph/trunk/src/osgShadow/ShadowMap.cpp (modified) (6 diffs)

OpenSceneGraph/trunk/src/osgShadow/ShadowMap.cpp

@@ -82 +82 @@
     _baseTextureUnit(0),
         _shadowTextureUnit(1),
-        _ambientBias(0.3f,1.2f),
+        _ambientBias(0.5f,0.5f),
         _textureSize(1024,1024)
     {
@@ -134 +134 @@
         _uniformList.push_back(shadowTextureSampler);
 
-        osg::Uniform* ambientBias = new osg::Uniform("osgShadow_ambientBias",_ambientBias);
-        _uniformList.push_back(ambientBias);
+        _ambientBiasUniform = new osg::Uniform("osgShadow_ambientBias",_ambientBias);
+        _uniformList.push_back(_ambientBiasUniform.get());
 
     }
@@ -202 +202 @@
             osg::StateSet* stateset = _camera->getOrCreateStateSet();
 
-            float factor = 0.0f;
-            float units = 1.0f;
+
+#if 1
+            // cull front faces so that only backfaces contribute to depth map
+
+            osg::ref_ptr<osg::CullFace> cull_face = new osg::CullFace;
+            cull_face->setMode(osg::CullFace::FRONT);
+            stateset->setAttribute(cull_face.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
+            stateset->setMode(GL_CULL_FACE, osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
+
+            // negative polygonoffset - move the backface nearer to the eye point so that backfaces
+            // shadow themselves
+            float factor = -1.0f;
+            float units = -1.0f;
 
             osg::ref_ptr<osg::PolygonOffset> polygon_offset = new osg::PolygonOffset;
@@ -210 +221 @@
             stateset->setAttribute(polygon_offset.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
             stateset->setMode(GL_POLYGON_OFFSET_FILL, osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
-
-            osg::ref_ptr<osg::CullFace> cull_face = new osg::CullFace;
-            cull_face->setMode(osg::CullFace::FRONT);
-            stateset->setAttribute(cull_face.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
-            stateset->setMode(GL_CULL_FACE, osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
-
+#else
+            // disabling cull faces so that only front and backfaces contribute to depth map
+            stateset->setMode(GL_CULL_FACE, osg::StateAttribute::OFF | osg::StateAttribute::OVERRIDE);
+
+            // negative polygonoffset - move the backface nearer to the eye point
+            // so that front faces do not shadow themselves.
+            float factor = 1.0f;
+            float units = 1.0f;
+
+            osg::ref_ptr<osg::PolygonOffset> polygon_offset = new osg::PolygonOffset;
+            polygon_offset->setFactor(factor);
+            polygon_offset->setUnits(units);
+            stateset->setAttribute(polygon_offset.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
+            stateset->setMode(GL_POLYGON_OFFSET_FILL, osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
+#endif
         }
 
@@ -353 +373 @@
             }
         }
-
+        
         osg::Matrix eyeToWorld;
         eyeToWorld.invert(*cv.getModelViewMatrix());
@@ -364 +384 @@
         if (selectLight)
         {
+
+            // set to ambient on light to black so that the ambient bias uniform can take it's affect
+            const_cast<osg::Light*>(selectLight)->setAmbient(osg::Vec4(0.0f,0.0f,0.0f,1.0f));
 
             //std::cout<<"----- VxOSG::ShadowMap selectLight spot cutoff "<<selectLight->getSpotCutoff()<<std::endl;