Question

Can anyone give me a reference to sites, blogs, articles, or post themselves a crash course or easy help guide in 2-D collision detection for Android? I looked at collision code from an online tutorial but they didn’t explain the collision part of the code – just the part of implementing sprites. I am not using OpenGL, I am using Canvas for my game. I have searched around but I keep finding stuff for OpenGL or C++ but I am using Java. Code examples that are explained would be highly appreciated. Thanks for any help you can offer.

Answer 1

colliding rectangles is easiest (actually circles are but with sprites your not using those)

for 2 rectangles to collide/overlap some space needs to be shared

public class Sprite{
    private int left,right;//bounding box left<right and top>bottom
    private int top,bottom;

    public final boolean collidesWith(Sprite other){
        if(this.left>other.right || other.left>other.right)return false;
        if(this.bottom>other.top || other.bottom>other.top)return false;

        return true;
    }
}

for getting which ones collide you can sweep over the entire board and check all the overlap in one dimension