Changeset 7913 for OpenSceneGraph/trunk/src/osgShadow/ShadowMap.cpp

Timestamp:

03/04/08 17:22:47 (5 years ago)

Author:

robert

Message:

From Wojciech Lewandowski, "Attached is modified osgShadow::ShadowMap?. I changed following things:

1:
Shadow map camera sets ABSOLUTE_RF_INHERIT_VIEWPOINT refernce frame.

2:
Light Direction by matrix multiplications replaced with transform3x3 multiplication.

3:
I made DebugingHUD functional by adding special draw callback. Former version was simply drawing pale square.

4:
I was tempted to make 4 th change but decided to not do it. Instead I put it whith #if VIEW_DEPNDENT_TEXGEN. If you decide you may let it go.

When objects are not centered at 0,0,0 coord but in some distant location (for example at surface of earth ellipsoid) shadow texgen suffers from inadequate precision of float matrices. I changed that by premultiplying Texgen matrix (using OSG double matrices) with inverse modelview and applying it later with ModelView? identity matrix. This tweak may be appropriate for OverlayNode? texgen as well.

I left former version because I suspect that this change will make osgShadow::ShadowMap? view dependant. Currently texgen matrix remains the same no matter what View displays it. With my change it wuld be different for each view. This touches the subject of View Dependent Shadow Techniques that J-S asked recently."

Files:

• OpenSceneGraph/trunk/src/osgShadow/ShadowMap.cpp (modified) (14 diffs)

OpenSceneGraph/trunk/src/osgShadow/ShadowMap.cpp

@@ -29 +29 @@
 #include <osgDB/ReadFile>
 #include <osgText/Text>
+
+#define IMPROVE_TEXGEN_PRECISION 1
 
 //////////////////////////////////////////////////////////////////
@@ -75 +77 @@
     "{ \n"
     "   vec4 texResult = texture2D(osgShadow_shadowTexture, gl_TexCoord[0].st ); \n"
-    "   float value = texResult.r + 0.5; \n"
+    "   float value = texResult.r; \n"
     "   gl_FragColor = vec4( value, value, value, 0.8 ); \n"
     "} \n";
@@ -180 +182 @@
         // create the camera
         _camera = new osg::Camera;
+
+        _camera->setReferenceFrame(osg::Camera::ABSOLUTE_RF_INHERIT_VIEWPOINT);
 
         _camera->setCullCallback(new CameraCullCallback(this));
@@ -364 +368 @@
             {
                 lightpos = light->getPosition() * (*matrix);
-                lightDir = light->getDirection() * (*matrix);
+                lightDir = osg::Matrix::transform3x3( light->getDirection(), *matrix );
             }
             else 
@@ -378 +382 @@
     eyeToWorld.invert(*cv.getModelViewMatrix());
 
-    lightpos = lightpos * eyeToWorld;
-    //MR do we do this for the direction also ? preliminary Yes, but still no good result
-    lightDir = lightDir * eyeToWorld;
+    lightpos = lightpos * eyeToWorld;     
+    lightDir = osg::Matrix::transform3x3( lightDir, eyeToWorld );
     lightDir.normalize();
 
@@ -395 +398 @@
             osg::Vec3 position(lightpos.x(), lightpos.y(), lightpos.z());
             float spotAngle = selectLight->getSpotCutoff();
-            _camera->setReferenceFrame(osg::Camera::ABSOLUTE_RF);
             _camera->setProjectionMatrixAsPerspective(spotAngle, 1.0, 0.1, 1000.0);
             _camera->setViewMatrixAsLookAt(position,position+lightDir,osg::Vec3(0.0f,1.0f,0.0f));
@@ -423 +425 @@
                 float right = top;
 
-                _camera->setReferenceFrame(osg::Camera::ABSOLUTE_RF);
                 _camera->setProjectionMatrixAsFrustum(-right,right,-top,top,znear,zfar);
                 _camera->setViewMatrixAsLookAt(position,bb.center(),osg::Vec3(0.0f,1.0f,0.0f));
@@ -446 +447 @@
                 float right = top;
 
-                _camera->setReferenceFrame(osg::Camera::ABSOLUTE_RF);
                 _camera->setProjectionMatrixAsOrtho(-right, right, -top, top, znear, zfar);
                 _camera->setViewMatrixAsLookAt(position,bb.center(),osg::Vec3(0.0f,1.0f,0.0f));
@@ -453 +453 @@
 
         }
-            // compute the matrix which takes a vertex from local coords into tex coords
-            // will use this later to specify osg::TexGen..
-            osg::Matrix MVPT = _camera->getViewMatrix() * 
-                _camera->getProjectionMatrix() *
-                osg::Matrix::translate(1.0,1.0,1.0) *
-                osg::Matrix::scale(0.5f,0.5f,0.5f);
-
-            _texgen->setMode(osg::TexGen::EYE_LINEAR);
-            _texgen->setPlanesFromMatrix(MVPT);
 
         cv.setTraversalMask( traversalMask & 
@@ -469 +460 @@
         _camera->accept(cv);
 
+        _texgen->setMode(osg::TexGen::EYE_LINEAR);
+
+#if IMPROVE_TEXGEN_PRECISION
+        // compute the matrix which takes a vertex from local coords into tex coords
+        // We actually use two matrices one used to define texgen
+        // and second that will be used as modelview when appling to OpenGL
+        _texgen->setPlanesFromMatrix( _camera->getProjectionMatrix() *
+                                      osg::Matrix::translate(1.0,1.0,1.0) *
+                                      osg::Matrix::scale(0.5f,0.5f,0.5f) );
+
+        // Place texgen with modelview which removes big offsets (making it float friendly)
+        osg::RefMatrix * refMatrix = new osg::RefMatrix
+            ( _camera->getInverseViewMatrix() * *cv.getModelViewMatrix() );
+
+        cv.getRenderStage()->getPositionalStateContainer()->
+             addPositionedTextureAttribute( _shadowTextureUnit, refMatrix, _texgen.get() );
+#else 
+        // compute the matrix which takes a vertex from local coords into tex coords
+        // will use this later to specify osg::TexGen..
+        osg::Matrix MVPT = _camera->getViewMatrix() * 
+               _camera->getProjectionMatrix() *
+               osg::Matrix::translate(1.0,1.0,1.0) *
+               osg::Matrix::scale(0.5f,0.5f,0.5f);
+
+        _texgen->setPlanesFromMatrix(MVPT);
+
         orig_rs->getPositionalStateContainer()->addPositionedTextureAttribute(_shadowTextureUnit, cv.getModelViewMatrix(), _texgen.get());
+#endif
     } // if(selectLight)
 
@@ -483 +501 @@
 ///////////////////// Debug Methods
 
+////////////////////////////////////////////////////////////////////////////////
+// Callback used by debugging hud to display Shadow Map in color buffer
+// OSG does not allow to use the same GL Texture Id with different glTexParams. 
+// Callback simply turns shadow compare mode off via GL while rendering hud and 
+// restores it afterwards. 
+////////////////////////////////////////////////////////////////////////////////
+class DrawableDrawWithDepthShadowComparisonOffCallback: 
+    public osg::Drawable::DrawCallback
+{
+public:
+    // 
+    DrawableDrawWithDepthShadowComparisonOffCallback
+        ( osg::Texture2D * texture, unsigned stage = 0 )
+            : _texture( texture ), _stage( stage )
+    {
+    }
+
+    virtual void drawImplementation
+        ( osg::RenderInfo & ri,const osg::Drawable* drawable ) const
+    {
+        if( _texture.valid() ) {
+            // make sure proper texture is currently applied
+            ri.getState()->applyTextureAttribute( _stage, _texture.get() );
+
+            // Turn off depth comparison mode
+            glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, 
+                             GL_NONE );
+        }
+
+        drawable->drawImplementation(ri);
+
+        if( _texture.valid() ) {
+            // Turn it back on
+            glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, 
+                             GL_COMPARE_R_TO_TEXTURE_ARB );
+        }
+    }
+
+    unsigned                       _stage;
+    osg::ref_ptr< osg::Texture2D > _texture;
+};
+////////////////////////////////////////////////////////////////////////////////
 osg::ref_ptr<osg::Camera> ShadowMap::makeDebugHUD()
 {
+    // Make sure we attach initialized texture to HUD
+    if( !_texture.valid() )    init();
+
     osg::ref_ptr<osg::Camera> camera = new osg::Camera;
 
@@ -510 +573 @@
     osg::Vec3 position(10.0f,size.y()-100.0f,0.0f);
     osg::Vec3 delta(0.0f,-120.0f,0.0f); 
-    float lenght = 300.0f;
+    float length = 300.0f;
 
     // turn the text off to avoid linking with osgText
@@ -528 +591 @@
 #endif
 
-    osg::Vec3 widthVec(lenght, 0.0f, 0.0f);
-    osg::Vec3 depthVec(0.0f,lenght, 0.0f);
-    osg::Vec3 centerBase( 10.0f + lenght/2, size.y()-lenght/2, 0.0f);
+    osg::Vec3 widthVec(length, 0.0f, 0.0f);
+    osg::Vec3 depthVec(0.0f,length, 0.0f);
+    osg::Vec3 centerBase( 10.0f + length/2, size.y()-length/2, 0.0f);
     centerBase += delta;
 
-    geode->addDrawable( osg::createTexturedQuadGeometry( centerBase-widthVec*0.5f-depthVec*0.5f, 
-                                                         widthVec, depthVec) );
+    osg::Geometry *geometry = osg::createTexturedQuadGeometry
+        ( centerBase-widthVec*0.5f-depthVec*0.5f, widthVec, depthVec );
+
+    geode->addDrawable( geometry );
+
+    geometry->setDrawCallback
+        ( new DrawableDrawWithDepthShadowComparisonOffCallback( _texture.get() ) );
 
     osg::StateSet* stateset = geode->getOrCreateStateSet();
@@ -544 +612 @@
 
     // test with regular texture
-    //stateset->setTextureAttributeAndModes(_baseTextureUnit, new osg::Texture2D(osgDB::readImageFile("Images/lz.rgb")));
-
-    stateset->setTextureAttributeAndModes(_shadowTextureUnit,_texture.get(),osg::StateAttribute::ON);
+    //stateset->setTextureAttributeAndModes(0, new osg::Texture2D(osgDB::readImageFile("Images/lz.rgb")));
+
+    stateset->setTextureAttributeAndModes(0,_texture.get(),osg::StateAttribute::ON);
 
     //test to check the texture coordinates generated during shadow pass