void CC3Matrix::populateToLookAt( const CC3Vector& targetLocation, const CC3Vector& eyeLocation, const CC3Vector& upDirection )
{
CC3Vector fwdDir = targetLocation.difference( eyeLocation );
populateToPointTowards( fwdDir, upDirection );
transpose();
translateBy( eyeLocation.negate() );
m_isIdentity = false;
m_isRigid = true;
}
/**
* Returns a 4D directional vector which can be added to each vertex when creating
* the shadow volume vertices from the corresponding shadow caster vertices.
*
* The returned vector is in the local coordinate system of the shadow caster.
*
* The returned directional vector is a small offset vector in the direction away
* from the light. A unit vector in that direction is scaled by both the distance
* from the center of the shadow casting node to the camera and the
* shadowVolumeVertexOffsetFactor property. Hence, if the shadow caster is farther
* away from the camera, the returned value will be larger, to reduce the chance
* of Z-fighting between the faces of the shadow volume and the shadow caster.
*/
CC3Vector4 CC3ShadowVolumeMeshNode::getShadowVolumeVertexOffsetForLightAt( const CC3Vector4& localLightPos )
{
CC3Vector scLoc = getShadowCaster()->getLocalContentCenterOfGeometry();
CC3Vector lgtLoc = localLightPos.cc3Vector();
CC3Vector camLoc = getShadowCaster()->getGlobalTransformMatrixInverted()->transformLocation( getActiveCamera()->getGlobalLocation() );
// Get a unit offset vector in the direction away from the light
CC3Vector offsetDir = (_light->isDirectionalOnly()
? lgtLoc.negate()
: scLoc.difference( lgtLoc )).normalize();
// Get the distance from the shadow caster CoG and the camera, and scale the
// unit offset vector by that distance and the shadowVolumeVertexOffsetFactor
GLfloat camDist = scLoc.distance( camLoc );
CC3Vector offset = offsetDir.scaleUniform( camDist * _shadowVolumeVertexOffsetFactor );
CC3_TRACE("CC3ShadowVolumeMeshNode nudging vertices by %s", offset.stringfy().c_str());
// Create and return a 4D directional vector from the offset
return CC3Vector4().fromDirection(offset);
}
void CC3PointParticle::pointNormalAt( const CC3Vector& camLoc )
{
setNormal( camLoc.difference( getLocation() ).normalize() );
}
