bool Brush::intersectsBrush(const Brush& brush) const {
if (!bounds().intersects(brush.bounds()))
return false;
// separating axis theorem
// http://www.geometrictools.com/Documentation/MethodOfSeparatingAxes.pdf
FaceList::const_iterator faceIt, faceEnd;
const VertexList& myVertices = vertices();
const FaceList& theirFaces = brush.faces();
for (faceIt = theirFaces.begin(), faceEnd = theirFaces.end(); faceIt != faceEnd; ++faceIt) {
const Face& theirFace = **faceIt;
const Vec3f& origin = theirFace.vertices().front()->position;
const Vec3f& direction = theirFace.boundary().normal;
if (vertexStatusFromRay(origin, direction, myVertices) == PointStatus::PSAbove)
return false;
}
const VertexList& theirVertices = brush.vertices();
for (faceIt = m_faces.begin(), faceEnd = m_faces.end(); faceIt != faceEnd; ++faceIt) {
const Face& myFace = **faceIt;
const Vec3f& origin = myFace.vertices().front()->position;
const Vec3f& direction = myFace.boundary().normal;
if (vertexStatusFromRay(origin, direction, theirVertices) == PointStatus::PSAbove)
return false;
}
const EdgeList& myEdges = edges();
const EdgeList& theirEdges = brush.edges();
EdgeList::const_iterator myEdgeIt, myEdgeEnd, theirEdgeIt, theirEdgeEnd;
for (myEdgeIt = myEdges.begin(), myEdgeEnd = myEdges.end(); myEdgeIt != myEdgeEnd; ++myEdgeIt) {
const Edge& myEdge = **myEdgeIt;
for (theirEdgeIt = theirEdges.begin(), theirEdgeEnd = theirEdges.end(); theirEdgeIt != theirEdgeEnd; ++theirEdgeIt) {
const Edge& theirEdge = **theirEdgeIt;
const Vec3f myEdgeVec = myEdge.vector();
const Vec3f theirEdgeVec = theirEdge.vector();
const Vec3f& origin = myEdge.start->position;
const Vec3f direction = crossed(myEdgeVec, theirEdgeVec);
PointStatus::Type myStatus = vertexStatusFromRay(origin, direction, myVertices);
if (myStatus != PointStatus::PSInside) {
PointStatus::Type theirStatus = vertexStatusFromRay(origin, direction, theirVertices);
if (theirStatus != PointStatus::PSInside) {
if (myStatus != theirStatus)
return false;
}
}
}
}
return true;
}
