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OpenSceneGraph/src/osgShadow/MinimalShadowMap.cpp

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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* OpenSceneGraph Public License for more details.
*
* ViewDependentShadow codes Copyright (C) 2008 Wojciech Lewandowski
* Thanks to to my company http://www.ai.com.pl for allowing me free this work.
*/
#include <osgShadow/MinimalShadowMap>
#include <osgShadow/ConvexPolyhedron>
#include <osg/MatrixTransform>
#include <osgShadow/ShadowedScene>
#include <osg/ComputeBoundsVisitor>
using namespace osgShadow;
#define PRINT_SHADOW_TEXEL_TO_PIXEL_ERROR 0
MinimalShadowMap::MinimalShadowMap():
BaseClass(),
_maxFarPlane( FLT_MAX ),
_minLightMargin( 0 ),
_shadowReceivingCoarseBoundAccuracy( BOUNDING_BOX )
{
}
MinimalShadowMap::MinimalShadowMap
(const MinimalShadowMap& copy, const osg::CopyOp& copyop) :
BaseClass(copy,copyop),
_maxFarPlane( copy._maxFarPlane ),
_minLightMargin( copy._minLightMargin ),
_shadowReceivingCoarseBoundAccuracy( copy._shadowReceivingCoarseBoundAccuracy )
{
}
MinimalShadowMap::~MinimalShadowMap()
{
}
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::aimShadowCastingCamera(
const osg::BoundingSphere &bs,
const osg::Light *light,
const osg::Vec4 &lightPos,
const osg::Vec3 &lightDir,
const osg::Vec3 &lightUpVector
/* by default = osg::Vec3( 0, 1 0 )*/ )
{
BaseClass::ViewData::aimShadowCastingCamera( bs, light, lightPos, lightDir, lightUpVector );
}
void MinimalShadowMap::ViewData::aimShadowCastingCamera
( const osg::Light *light, const osg::Vec4 &lightPos,
const osg::Vec3 &lightDir, const osg::Vec3 &lightUp )
{
osg::BoundingBox bb = computeScenePolytopeBounds();
if( !bb.valid() ) { // empty scene or looking at the sky - substitute something
bb.expandBy( osg::BoundingSphere( _cv->getEyePoint(), 1 ) );
}
osg::Vec3 up = lightUp;
if( up.length2() <= 0 )
{
// This is extra step (not really needed but helpful in debuging)
// Compute such lightUp vector that shadow cam is intuitively aligned with eye
// We compute this vector on -ZY view plane, perpendicular to light direction
// Matrix m = ViewToWorld
#if 0
osg::Matrix m = osg::Matrix::inverse( _cv->getModelViewMatrix() );
osg::Vec3 camFw( -m( 2, 0 ), -m( 2, 1 ), -m( 2, 2 ) );
camFw.normalize();
osg::Vec3 camUp( m( 1, 0 ), m( 1, 1 ), m( 1, 2 ) );
camUp.normalize();
up = camUp * ( camFw * lightDir ) - camFw * ( camUp * lightDir );
up.normalize();
#else
osg::Matrix m = osg::Matrix::inverse( *_cv->getModelViewMatrix() );
// OpenGL std cam looks along -Z axis so Cam Fw = [ 0 0 -1 0 ] * m
up.set( -m( 2, 0 ), -m( 2, 1 ), -m( 2, 2 ) );
#endif
}
aimShadowCastingCamera( osg::BoundingSphere( bb ), light, lightPos, lightDir, up );
// Intersect scene Receiving Shadow Polytope with shadow camera frustum
// Important for cases where Scene extend beyond shadow camera frustum
// From this moment shadowed scene portion is fully contained by both
// main camera frustum and shadow camera frustum
osg::Matrix mvp = _camera->getViewMatrix() * _camera->getProjectionMatrix();
cutScenePolytope( osg::Matrix::inverse( mvp ), mvp );
frameShadowCastingCamera
( _cv->getRenderStage()->getCamera(), _camera.get(), 0 );
}
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();
}
}
}
void MinimalShadowMap::ViewData::cullShadowReceivingScene( )
{
BaseClass::ViewData::cullShadowReceivingScene( );
_clampedProjection = *_cv->getProjectionMatrix();
if( _cv->getComputeNearFarMode() ) {
// Redo steps from CullVisitor::popProjectionMatrix()
// which clamps projection matrix when Camera & Projection
// completes traversal of their children
// We have to do this now manually
// because we did not complete camera traversal yet but
// we need to know how this clamped projection matrix will be
_cv->computeNearPlane();
osgUtil::CullVisitor::value_type n = _cv->getCalculatedNearPlane();
osgUtil::CullVisitor::value_type f = _cv->getCalculatedFarPlane();
if( n < f )
_cv->clampProjectionMatrix( _clampedProjection, n, f );
}
// Aditionally clamp far plane if shadows don't need to be cast as
// far as main projection far plane
if( 0 < *_maxFarPlanePtr )
clampProjection( _clampedProjection, 0.f, *_maxFarPlanePtr );
// Give derived classes chance to initialize _sceneReceivingShadowPolytope
osg::BoundingBox bb = computeShadowReceivingCoarseBounds( );
if( bb.valid() )
_sceneReceivingShadowPolytope.setToBoundingBox( bb );
else
_sceneReceivingShadowPolytope.clear();
// Cut initial scene using main camera frustum.
// Cutting will work correctly on empty polytope too.
// Take into consideration near far calculation and _maxFarPlane variable
osg::Matrix mvp = *_cv->getModelViewMatrix() * _clampedProjection;
cutScenePolytope( osg::Matrix::inverse( mvp ), mvp );
setDebugPolytope
( "frustum", _sceneReceivingShadowPolytope, osg::Vec4(1,0,1,1));
}
void MinimalShadowMap::ViewData::init( ThisClass *st, osgUtil::CullVisitor *cv )
{
BaseClass::ViewData::init( st, cv );
_modellingSpaceToWorldPtr = &st->_modellingSpaceToWorld;
_minLightMarginPtr = &st->_minLightMargin;
_maxFarPlanePtr = &st->_maxFarPlane;
_frameShadowCastingCameraPasses = 1;
}
void MinimalShadowMap::ViewData::cutScenePolytope
( const osg::Matrix & transform,
const osg::Matrix & inverse,
const osg::BoundingBox & bb )
{
_sceneReceivingShadowPolytopePoints.clear();
if( bb.valid() ) {
osg::Polytope polytope;
polytope.setToBoundingBox( bb );
polytope.transformProvidingInverse( inverse );
_sceneReceivingShadowPolytope.cut( polytope );
_sceneReceivingShadowPolytope.getPoints
( _sceneReceivingShadowPolytopePoints );
} else
_sceneReceivingShadowPolytope.clear();
}
osg::BoundingBox
MinimalShadowMap::ViewData::computeScenePolytopeBounds( const osg::Matrix & m )
{
osg::BoundingBox bb;
if( &m )
for( unsigned i = 0; i < _sceneReceivingShadowPolytopePoints.size(); ++i )
bb.expandBy( _sceneReceivingShadowPolytopePoints[i] * m );
else
for( unsigned i = 0; i < _sceneReceivingShadowPolytopePoints.size(); ++i )
bb.expandBy( _sceneReceivingShadowPolytopePoints[i] );
return bb;
}
// Utility methods for adjusting projection matrices
void MinimalShadowMap::ViewData::trimProjection
( osg::Matrixd & projectionMatrix, osg::BoundingBox bb, unsigned int trimMask )
{
#if 1
if( !bb.valid() || !( trimMask & (1|2|4|8|16|32) ) ) return;
double l = -1, r = 1, b = -1, t = 1, n = 1, f = -1;
#if 0
// make sure bounding box does not extend beyond unit frustum clip range
for( int i = 0; i < 3; i ++ ) {
if( bb._min[i] < -1 ) bb._min[i] = -1;
if( bb._max[i] > 1 ) bb._max[i] = 1;
}
#endif
if( trimMask & 1 ) l = bb._min[0];
if( trimMask & 2 ) r = bb._max[0];
if( trimMask & 4 ) b = bb._min[1];
if( trimMask & 8 ) t = bb._max[1];
if( trimMask & 16 ) n = -bb._min[2];
if( trimMask & 32 ) f = -bb._max[2];
projectionMatrix.postMult( osg::Matrix::ortho( l,r,b,t,n,f ) );
#else
if( !bb.valid() || !( trimMask & (1|2|4|8|16|32) ) ) return;
double l, r, t, b, n, f;
bool ortho = projectionMatrix.getOrtho( l, r, b, t, n, f );
if( !ortho && !projectionMatrix.getFrustum( l, r, b, t, n, f ) )
return; // rotated or skewed or other crooked projection - give up
// make sure bounding box does not extend beyond unit frustum clip range
for( int i = 0; i < 3; i ++ ) {
if( bb._min[i] < -1 ) bb._min[i] = -1;
if( bb._max[i] > 1 ) bb._max[i] = 1;
}
osg::Matrix projectionToView = osg::Matrix::inverse( projectionMatrix );
osg::Vec3 min =
osg::Vec3( bb._min[0], bb._min[1], bb._min[2] ) * projectionToView;
osg::Vec3 max =
osg::Vec3( bb._max[0], bb._max[1], bb._max[2] ) * projectionToView;
if( trimMask & 16 ) { // trim near
if( !ortho ) { // recalc frustum corners on new near plane
l *= -min[2] / n;
r *= -min[2] / n;
b *= -min[2] / n;
t *= -min[2] / n;
}
n = -min[2];
}
if( trimMask & 32 ) // trim far
f = -max[2];
if( !ortho ) {
min[0] *= -n / min[2];
min[1] *= -n / min[2];
max[0] *= -n / max[2];
max[1] *= -n / max[2];
}
if( l < r ) { // check for inverted X range
if( l < min[0] && ( trimMask & 1 ) ) l = min[0];
if( r > max[0] && ( trimMask & 2 ) ) r = max[0];
} else {
if( l > min[0] && ( trimMask & 1 ) ) l = min[0];
if( r < max[0] && ( trimMask & 2 ) ) r = max[0];
}
if( b < t ) { // check for inverted Y range
if( b < min[1] && ( trimMask & 4 ) ) b = min[1];
if( t > max[1] && ( trimMask & 8 ) ) t = max[1];
} else {
if( b > min[1] && ( trimMask & 4 ) ) b = min[1];
if( t < max[1] && ( trimMask & 8 ) ) t = max[1];
}
if( ortho )
projectionMatrix.makeOrtho( l, r, b, t, n, f );
else
projectionMatrix.makeFrustum( l, r, b, t, n, f );
#endif
}
void MinimalShadowMap::ViewData::clampProjection
( osg::Matrixd & projection, float new_near, float new_far )
{
double r, l, t, b, n, f;
bool perspective = projection.getFrustum( l, r, b, t, n, f );
if( !perspective && !projection.getOrtho( l, r, b, t, n, f ) )
{
// What to do here ?
OSG_WARN << "MinimalShadowMap::clampProjectionFarPlane failed - non standard matrix" << std::endl;
} else if( n < new_near || new_far < f ) {
if( n < new_near && new_near < f ) {
if( perspective ) {
l *= new_near / n;
r *= new_near / n;
b *= new_near / n;
t *= new_near / n;
}
n = new_near;
}
if( n < new_far && new_far < f ) {
f = new_far;
}
if( perspective )
projection.makeFrustum( l, r, b, t, n, f );
else
projection.makeOrtho( l, r, b, t, n, f );
}
}
// Imagine following scenario:
// We stand in the room and look through the window.
// How should our view change if we were looking through larger window ?
// In other words how should projection be adjusted if
// window had grown by some margin ?
// Method computes such new projection which maintains perpective/world ratio
void MinimalShadowMap::ViewData::extendProjection
( osg::Matrixd & projection, osg::Viewport * viewport, const osg::Vec2& margin )
{
double l,r,b,t,n,f;
//osg::Matrix projection = camera.getProjectionMatrix();
bool frustum = projection.getFrustum( l,r,b,t,n,f );
if( !frustum && !projection.getOrtho( l,r,b,t,n,f ) ) {
OSG_WARN << " Awkward projection matrix. ComputeExtendedProjection failed" << std::endl;
return;
}
osg::Matrix window = viewport->computeWindowMatrix();
osg::Vec3 vMin( viewport->x() - margin.x(),
viewport->y() - margin.y(),
0.0 );
osg::Vec3 vMax( viewport->width() + margin.x() * 2 + vMin.x(),
viewport->height() + margin.y() * 2 + vMin.y(),
0.0 );
osg::Matrix inversePW = osg::Matrix::inverse( projection * window );
vMin = vMin * inversePW;
vMax = vMax * inversePW;
l = vMin.x();
r = vMax.x();
b = vMin.y();
t = vMax.y();
if( frustum )
projection.makeFrustum( l,r,b,t,n,f );
else
projection.makeOrtho( l,r,b,t,n,f );
}