Advanced Collision Detection Algorithms

[Boop]

Most of this stuff is described in math(geometry?) textbooks. Especially circle collisions and stuff.

I wrote this for a crappy android(https://play.google.com/store/apps/detai...Hobo&hl=en) game I made a (long)while back: http://slexy.org/raw/s21Bsi6YvL


The hobo was a circle. Cars were polygons. To check if a circle overlaps with a polygon I just iterated over each vector in the polygon and checked if it(the vector) overlapped with the circle. There is a tiny optimisation where before checking all the vectors in the polygon I first check if the the circle is inside the rectangle at all (since you can do that pretty fast).

Code:

        for (int x = 0; x < 4; x++)
        {
            List<Vehicle> cars = this.cars[x];
            int len = cars.size();
            for (int i = 0; i < len; i++) {
                Vehicle car = cars.get(i);
                if (OverlapTester.overlapCircleRectangle(car.bounds, hobo.circleBounds)) {
                    for (int j =0; j < car.boundingPolygon.length - 1; j++)
                    {
                        if (OverlapTester.testCircleSegment(hobo.circleBounds, car.boundingPolygon[j], car.boundingPolygon[j+1]))
                        {
                            hobo.hitCar();
                            listener.hit();
                            car.hit();
                        }
                    }
                }
            }
        }
    }

Code might be terrible, but it worked .

Edit: Looking over that code, you should stop iterating over the vectors which make up the polygon if you've already found an intersection. God damn it I suck at coding T_T