for (float x = MathUtils.floor(aabb.lowerBound.x / stride) * stride; x < upperBoundX; x +=
stride) {
Vec2 p = tempVec;
p.x = x;
p.y = y;
if (shape.testPoint(identity, p)) {
Transform.mulToOut(transform, p, p);
particleDef.position.x = p.x;
particleDef.position.y = p.y;
p.subLocal(groupDef.position);
Vec2.crossToOutUnsafe(groupDef.angularVelocity, p, particleDef.velocity);