osg::BoundingBox MinimalShadowMap::ViewData::computeShadowReceivingCoarseBounds()
{
// Default slowest but most precise
ShadowReceivingCoarseBoundAccuracy accuracy = DEFAULT_ACCURACY;
MinimalShadowMap * msm = dynamic_cast< MinimalShadowMap* >( _st.get() );
if( msm ) accuracy = msm->getShadowReceivingCoarseBoundAccuracy();
if( accuracy == MinimalShadowMap::EMPTY_BOX )
{
// One may skip coarse scene bounds computation if light is infinite.
// Empty box will be intersected with view frustum so in the end
// view frustum will be used as bounds approximation.
// But if light is nondirectional and bounds come out too large
// they may bring the effect of almost 180 deg perspective set
// up for shadow camera. Such projection will significantly impact
// precision of further math.
return osg::BoundingBox();
}
if( accuracy == MinimalShadowMap::BOUNDING_SPHERE )
{
// faster but less precise rough scene bound computation
// however if compute near far is active it may bring quite good result
osg::Camera * camera = _cv->getRenderStage()->getCamera();
osg::Matrix m = camera->getViewMatrix() * _clampedProjection;
ConvexPolyhedron frustum;
frustum.setToUnitFrustum();
frustum.transform( osg::Matrix::inverse( m ), m );
osg::BoundingSphere bs =_st->getShadowedScene()->getBound();
osg::BoundingBox bb;
bb.expandBy( bs );
osg::Polytope box;
box.setToBoundingBox( bb );
frustum.cut( box );
// approximate sphere with octahedron. Ie first cut by box then
// additionaly cut with the same box rotated 45, 45, 45 deg.
box.transform( // rotate box around its center
osg::Matrix::translate( -bs.center() ) *
osg::Matrix::rotate( osg::PI_4, 0, 0, 1 ) *
osg::Matrix::rotate( osg::PI_4, 1, 1, 0 ) *
osg::Matrix::translate( bs.center() ) );
frustum.cut( box );
return frustum.computeBoundingBox( );
}
if( accuracy == MinimalShadowMap::BOUNDING_BOX ) // Default
{
// more precise method but slower method
// bound visitor traversal takes lot of time for complex scenes
// (note that this adds to cull time)
osg::ComputeBoundsVisitor cbbv(osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN);
cbbv.setTraversalMask(_st->getShadowedScene()->getCastsShadowTraversalMask());
_st->getShadowedScene()->osg::Group::traverse(cbbv);
return cbbv.getBoundingBox();
}
return osg::BoundingBox();
}
void MinimalShadowMap::ViewData::frameShadowCastingCamera
( const osg::Camera* cameraMain, osg::Camera* cameraShadow, int pass )
{
osg::Matrix mvp =
cameraShadow->getViewMatrix() * cameraShadow->getProjectionMatrix();
ConvexPolyhedron polytope = _sceneReceivingShadowPolytope;
std::vector<osg::Vec3d> points = _sceneReceivingShadowPolytopePoints;
osg::BoundingBox bb = computeScenePolytopeBounds( mvp );
// projection was trimmed above, need to recompute mvp
if( bb.valid() && *_minLightMarginPtr > 0 ) {
// bb._max += osg::Vec3( 1, 1, 1 );
// bb._min -= osg::Vec3( 1, 1, 1 );
osg::Matrix transform = osg::Matrix::inverse( mvp );
// Code below was working only for directional lights ie when projection was ortho
// osg::Vec3d normal = osg::Matrix::transform3x3( osg::Vec3d( 0,0,-1)., transfrom );
// So I replaced it with safer code working with spot lights as well
osg::Vec3d normal =
osg::Vec3d(0,0,-1) * transform - osg::Vec3d(0,0,1) * transform;
normal.normalize();
_sceneReceivingShadowPolytope.extrude( normal * *_minLightMarginPtr );
// Zero pass does crude shadowed scene hull approximation.
// Its important to cut it to coarse light frustum properly
// at this stage.
// If not cut and polytope extends beyond shadow projection clip
// space (-1..1), it may get "twisted" by precisely adjusted shadow cam
// projection in second pass.
if ( pass == 0 && _frameShadowCastingCameraPasses > 1 )
{ // Make sure extruded polytope does not extend beyond light frustum
osg::Polytope lightFrustum;
lightFrustum.setToUnitFrustum();
lightFrustum.transformProvidingInverse( mvp );
_sceneReceivingShadowPolytope.cut( lightFrustum );
}
_sceneReceivingShadowPolytopePoints.clear();
_sceneReceivingShadowPolytope.getPoints
( _sceneReceivingShadowPolytopePoints );
bb = computeScenePolytopeBounds( mvp );
}
setDebugPolytope( "extended",
_sceneReceivingShadowPolytope, osg::Vec4( 1, 0.5, 0, 1 ), osg::Vec4( 1, 0.5, 0, 0.1 ) );
_sceneReceivingShadowPolytope = polytope;
_sceneReceivingShadowPolytopePoints = points;
// Warning: Trim light projection at near plane may remove shadowing
// from objects outside of view space but still casting shadows into it.
// I have not noticed this issue so I left mask at default: all bits set.
if( bb.valid() )
trimProjection( cameraShadow->getProjectionMatrix(), bb, 1|2|4|8|16|32 );
///// Debuging stuff //////////////////////////////////////////////////////////
setDebugPolytope( "scene", _sceneReceivingShadowPolytope, osg::Vec4(0,1,0,1) );
#if PRINT_SHADOW_TEXEL_TO_PIXEL_ERROR
if( pass == 1 )
displayShadowTexelToPixelErrors
( cameraMain, cameraShadow, &_sceneReceivingShadowPolytope );
#endif
if( pass == _frameShadowCastingCameraPasses - 1 )
{
#if 1
{
osg::Matrix mvp = cameraShadow->getViewMatrix() * cameraShadow->getProjectionMatrix();
ConvexPolyhedron frustum;
frustum.setToUnitFrustum();
frustum.transform( osg::Matrix::inverse( mvp ), mvp );
setDebugPolytope( "shadowCamFrustum", frustum, osg::Vec4(0,0,1,1) );
}
{
osg::Matrix mvp = cameraMain->getViewMatrix() * cameraMain->getProjectionMatrix();
ConvexPolyhedron frustum;
frustum.setToUnitFrustum();
frustum.transform( osg::Matrix::inverse( mvp ), mvp );
setDebugPolytope( "mainCamFrustum", frustum, osg::Vec4(1,1,1,1) );
}
#endif
std::string * filename = getDebugDump( );
if( filename && !filename->empty() )
{
dump( *filename );
filename->clear();
}
}
}
