computeKey method
return a square envelope containing the argument envelope, whose extent is a power of two and which is based at a power of 2
Implementation
void computeKey(Envelope itemEnv) {
level = computeQuadLevel(itemEnv);
env = Envelope.empty();
computeKeyLevel(level, itemEnv);
// MD - would be nice to have a non-iterative form of this algorithm
while (!env.containsEnvelope(itemEnv)) {
level += 1;
computeKeyLevel(level, itemEnv);
}
}