//----------------------------------------------------------------//
void ZLFrustum::Init ( const ZLMatrix4x4& invViewProjMtx ) {
// set up the homogenous coordinates of the canonical view volume
ZLVec3D nlt ( -1.0f, 1.0f, -1.0f );
ZLVec3D nrt ( 1.0f, 1.0f, -1.0f );
ZLVec3D nrb ( 1.0f, -1.0f, -1.0f );
ZLVec3D nlb ( -1.0f, -1.0f, -1.0f );
ZLVec3D flt ( -1.0f, 1.0f, 1.0f );
ZLVec3D frt ( 1.0f, 1.0f, 1.0f );
ZLVec3D frb ( 1.0f, -1.0f, 1.0f );
ZLVec3D flb ( -1.0f, -1.0f, 1.0f );
// compute the corners of the frustum
invViewProjMtx.Project ( nlt );
invViewProjMtx.Project ( nrt );
invViewProjMtx.Project ( nrb );
invViewProjMtx.Project ( nlb );
invViewProjMtx.Project ( flt );
invViewProjMtx.Project ( frt );
invViewProjMtx.Project ( frb );
invViewProjMtx.Project ( flb );
this->mPoints [ NEAR_LT_POINT ].Init ( nlt.mX, nlt.mY, nlt.mZ );
this->mPoints [ NEAR_RT_POINT ].Init ( nrt.mX, nrt.mY, nrt.mZ );
this->mPoints [ NEAR_RB_POINT ].Init ( nrb.mX, nrb.mY, nrb.mZ );
this->mPoints [ NEAR_LB_POINT ].Init ( nlb.mX, nlb.mY, nlb.mZ );
this->mPoints [ FAR_LT_POINT ].Init ( flt.mX, flt.mY, flt.mZ );
this->mPoints [ FAR_RT_POINT ].Init ( frt.mX, frt.mY, frt.mZ );
this->mPoints [ FAR_RB_POINT ].Init ( frb.mX, frb.mY, frb.mZ );
this->mPoints [ FAR_LB_POINT ].Init ( flb.mX, flb.mY, flb.mZ );
// Compute the frustum's axis-aligned bounding box
this->mAABB.Init ( nlt );
this->mAABB.Grow ( nrt );
this->mAABB.Grow ( nrb );
this->mAABB.Grow ( nlb );
this->mAABB.Grow ( flt );
this->mAABB.Grow ( frt );
this->mAABB.Grow ( frb );
this->mAABB.Grow ( flb );
// intialize the planes
this->mPlanes [ LEFT_PLANE ].Init ( nlt, flt, flb );
this->mPlanes [ RIGHT_PLANE ].Init ( nrb, frb, frt );
this->mPlanes [ TOP_PLANE ].Init ( nrt, frt, flt );
this->mPlanes [ BOTTOM_PLANE ].Init ( nlb, flb, frb );
this->mPlanes [ NEAR_PLANE ].Init ( nrt, nlt, nlb );
this->mPlanes [ FAR_PLANE ].Init ( flt, frt, frb );
double frustArea = _frustArea ( *this );
double boxArea = this->mAABB.Area ();
this->mUsePlanesForCull = (( float )( frustArea / boxArea )) < MIN_FILL_RATIO;
}
//----------------------------------------------------------------//
ZLRect MOAIScissorRect::GetScissorRect ( const ZLMatrix4x4& worldToWndMtx ) const {
ZLVec3D vtx3D [ 4 ];
vtx3D [ 0 ].mX = this->mRect.mXMin;
vtx3D [ 0 ].mY = this->mRect.mYMin;
vtx3D [ 0 ].mZ = 0.0f;
vtx3D [ 1 ].mX = this->mRect.mXMin;
vtx3D [ 1 ].mY = this->mRect.mYMax;
vtx3D [ 1 ].mZ = 0.0f;
vtx3D [ 2 ].mX = this->mRect.mXMax;
vtx3D [ 2 ].mY = this->mRect.mYMax;
vtx3D [ 2 ].mZ = 0.0f;
vtx3D [ 3 ].mX = this->mRect.mXMax;
vtx3D [ 3 ].mY = this->mRect.mYMin;
vtx3D [ 3 ].mZ = 0.0f;
ZLMatrix4x4 mtx;
mtx.Init ( this->GetLocalToWorldMtx ());
mtx.Append ( worldToWndMtx );
mtx.Project ( vtx3D [ 0 ]);
mtx.Project ( vtx3D [ 1 ]);
mtx.Project ( vtx3D [ 2 ]);
mtx.Project ( vtx3D [ 3 ]);
ZLRect scissorRect;
scissorRect.Init ( vtx3D [ 0 ]);
scissorRect.Grow ( vtx3D [ 1 ]);
scissorRect.Grow ( vtx3D [ 2 ]);
scissorRect.Grow ( vtx3D [ 3 ]);
if ( this->mScissorRect ) {
ZLRect parentRect = this->mScissorRect->GetScissorRect ( worldToWndMtx );
parentRect.Clip ( scissorRect );
}
return scissorRect;
}