Collision2D

Collision2D is a simple collision calculator written in Java. It's currently in Alpha status / work in progress, but already usable.

Features:

• collision point calculation
• hitboxes consisting of many rectangles, forming more complex shapes
• usable with any kind of canvas (Android, Swing etc)
• very small interfaces (you can use your own entites, rectangles etc)
• test: 100% code coverage

Let's assume two entities:

Entity e = new Entity();
e.getHitBox().addRectangle(new Rectangle(0,0,100,100));

Entity f = new Entity();
f.getHitBox().addRectangle(new Rectangle(50,50,200,200));

You can check collisions on various levels, after calling the collision result:

CollisionResult collsion = e.getCollision(f);

First, you can check if a collision of two hitboxes is possible or not. This is a fast calculation, which will give you a hint on whenever you can check for more precise collisions:

boolean collisionIsPossible = collsion.hasSoftContact();

to check if a collision actually happened, you can check the hard contact:

boolean collisionHappened = collsion.hasHardContact();

You can also check for intersection points:

Iterator<CoordinatePoint> pointIterator = r.calculatePoints().iterator();
while (pointIterator.hasNext()) {
    System.out.println(pointIterator.next());
}

// will output: 
// X = 100.0 / Y = 50.0
// X = 50.0 / Y = 100.0

Todos / Work in progress:

• Complexity of Point calculation is unnecessarily high, reduce this
• Rectangles already have an optional name. Implement rectangle pair detection (ex. "leg" colliding with "head")