private static void r_rebound(PhysicActor actor, Rectangle rect, double dt) {
/*
* Employ a heuristic
* ------------
* | 0 |
* | 1 RECT 3 |
* | 2 |
* ------------
*/
actor.set_last_obstacle_collided(rect);
Vector actor_pos = actor.get_position().add(actor.get_velocity().multiply(dt));
Rectangle actor_mbr = actor.get().get_mbr();
double h[] = {
actor_pos.y + actor_mbr.y1 - rect.y2,
actor_pos.y + actor_mbr.y2 - rect.y1,
actor_pos.x + actor_mbr.x2 - rect.x1,
actor_pos.x + actor_mbr.x1 - rect.x2
};
for (int i = 0; i < 4; i++) h[i] = Math.abs(h[i]);
// now the question is - which of those is the smallest?
double smallest_val = Double.POSITIVE_INFINITY;
int smallest_index = -1;
for (int i = 0; i < 4; i++)
if (smallest_val > h[i]) {
smallest_val = h[i];
smallest_index = i;
}
assert (smallest_index != -1);
// ok, smallest_index is that
if (smallest_index == 0) // colliding with floor
Rebound.actor_hit_floor(actor, rect.y2, dt);
if (smallest_index == 1) // colliding with roof
Rebound.actor_hit_roof(actor, rect.y1, dt);
if (smallest_index == 2) {
Rebound.actor_hit_rightside(actor, rect.x1, dt);
if (actor.get_last_obstacle_collided() != rect) {
actor.set_v_braked(true);
actor.set_last_obstacle_collided(rect);
}
}
if (smallest_index == 3) {
Rebound.actor_hit_leftside(actor, rect.x2, dt);
if (actor.get_last_obstacle_collided() != rect) {
actor.set_v_braked(true);
actor.set_last_obstacle_collided(rect);
}
}
}
/**
* Rebound an actor by a LSG. Actor must collide with LSG.
*
* <p>Can mutate both position, velocity and flags. Will not touch anchor.
*/
public static void rebound(PhysicActor actor, LargeStaticGeometry lsg, double dt) {
// determine the colliding rect
for (Rectangle rect : lsg) {
if (actor.intersects(rect, dt)) {
Rebound.r_rebound(actor, rect, dt);
break;
}
}
}
/**
* Rebound an actor against a game world box. Actor must not be wholly contained within rect.
*
* @param actor the actor
* @param rect rectangle describing the box game is taking place within
* @param dt time delta
*/
public static void rebound(PhysicActor actor, Rectangle rect, double dt) {
Rectangle actor_mbr =
actor
.get()
.get_mbr()
.translate(actor.get_velocity().multiply(dt).add(actor.get_position()));
if (actor_mbr.y2 >= rect.y2) {
Rebound.actor_hit_roof(actor, rect.y2, dt);
}
if (actor_mbr.y1 <= rect.y1) {
Rebound.actor_hit_floor(actor, rect.y1, dt);
}
if (actor_mbr.x1 <= rect.x1) {
Rebound.actor_hit_leftside(actor, rect.x1, dt);
}
if (actor_mbr.x2 >= rect.x2) {
Rebound.actor_hit_rightside(actor, rect.x2, dt);
}
}