DiVec3 DiFocusedShadowPolicy::getNearCameraPoint_ws(const DiMat4& viewMatrix,
const PointListBody& bodyLVS) const
{
if (bodyLVS.getPointCount() == 0)
return DiVec3(0,0,0);
DiVec3 nearEye = viewMatrix * bodyLVS.getPoint(0), // for comparison
nearWorld = bodyLVS.getPoint(0); // represents the final point
// store the vertex with the highest z-value which is the nearest point
for (size_t i = 1; i < bodyLVS.getPointCount(); ++i)
{
const DiVec3& vWorld = bodyLVS.getPoint(i);
// comparison is done from the viewer
DiVec3 vEye = viewMatrix * vWorld;
if (vEye.z > nearEye.z)
{
nearEye = vEye;
nearWorld = vWorld;
}
}
return nearWorld;
}
DiMat4 DiFocusedShadowPolicy::transformToUnitCube(const DiMat4& m,
const PointListBody& body) const
{
// map the transformed body AAB points to the unit cube (-1/-1/-1) / (+1/+1/+1) corners
DiAABB aab_trans;
for (size_t i = 0; i < body.getPointCount(); ++i)
{
aab_trans.Merge(m * body.getPoint(i));
}
DiVec3 vMin, vMax;
vMin = aab_trans.GetMinimum();
vMax = aab_trans.GetMaximum();
const DiVec3 trans(-(vMax.x + vMin.x) / (vMax.x - vMin.x),
-(vMax.y + vMin.y) / (vMax.y - vMin.y),
-(vMax.z + vMin.z) / (vMax.z - vMin.z));
const DiVec3 scale(2 / (vMax.x - vMin.x),
2 / (vMax.y - vMin.y),
2 / (vMax.z - vMin.z));
DiMat4 mOut(DiMat4::IDENTITY);
mOut.setTrans(trans);
mOut.setScale(scale);
return mOut;
}
//-----------------------------------------------------------------------
Matrix4 FocusedShadowCameraSetup::transformToUnitCube(const Matrix4& m,
const PointListBody& body) const
{
// map the transformed body AAB points to the unit cube (-1/-1/-1) / (+1/+1/+1) corners
AxisAlignedBox aab_trans;
for (size_t i = 0; i < body.getPointCount(); ++i)
{
aab_trans.merge(m * body.getPoint(i));
}
Vector3 vMin, vMax;
vMin = aab_trans.getMinimum();
vMax = aab_trans.getMaximum();
const Vector3 trans(-(vMax.x + vMin.x) / (vMax.x - vMin.x),
-(vMax.y + vMin.y) / (vMax.y - vMin.y),
-(vMax.z + vMin.z) / (vMax.z - vMin.z));
const Vector3 scale(2 / (vMax.x - vMin.x),
2 / (vMax.y - vMin.y),
2 / (vMax.z - vMin.z));
Matrix4 mOut(Matrix4::IDENTITY);
mOut.setTrans(trans);
mOut.setScale(scale);
return mOut;
}
void DiFocusedShadowPolicy::PointListBody::merge(const PointListBody& plb)
{
size_t size = plb.getPointCount();
for (size_t i = 0; i < size; ++i)
{
this->addPoint(plb.getPoint(i));
}
}
//-----------------------------------------------------------------------
Matrix4 LiSPSMShadowCameraSetup::calculateLiSPSM(const Matrix4& lightSpace,
const PointListBody& bodyB, const PointListBody& bodyLVS,
const SceneManager& sm, const Camera& cam, const Light& light) const
{
// set up bodyB AAB in light space
AxisAlignedBox bodyBAAB_ls;
for (size_t i = 0; i < bodyB.getPointCount(); ++i)
{
bodyBAAB_ls.merge(lightSpace * bodyB.getPoint(i));
}
// near camera point in light space
const Vector3 e_ls = lightSpace * getNearCameraPoint_ws(cam.getViewMatrix(), bodyLVS);
// C_start has x and y of e and z from the bodyABB_ls (we look down the negative z axis, so take the maximum z value)
const Vector3 C_start_ls(e_ls.x, e_ls.y, bodyBAAB_ls.getMaximum().z);
// calculate the optimal distance between origin and near plane
Real n_opt;
if (mUseSimpleNOpt)
n_opt = calculateNOptSimple(bodyLVS, cam);
else
n_opt = calculateNOpt(lightSpace, bodyBAAB_ls, bodyLVS, cam);
// in case n_opt is null, uniform shadow mapping will be done
if (n_opt <= 0.0)
{
return Matrix4::IDENTITY;
}
// calculate the projection center C which is n units behind the near plane of P
// we look into the negative z direction so add n
const Vector3 C(C_start_ls + n_opt * Vector3::UNIT_Z);
// set up a transformation matrix to transform the light space to its new origin
Matrix4 lightSpaceTranslation(Matrix4::IDENTITY);
lightSpaceTranslation.setTrans(-C);
// range from bMin to bMax; d = |B_z_far - B_z_near|
Real d = Math::Abs(bodyBAAB_ls.getMaximum().z - bodyBAAB_ls.getMinimum().z);
// set up the LiSPSM perspective transformation
// build up frustum to map P onto the unit cube with (-1/-1/-1) and (+1/+1/+1)
Matrix4 P = buildFrustumProjection(-1, 1, -1, 1, n_opt, n_opt + d);
return P * lightSpaceTranslation;
}
