GameMaker 1.4 Flip X Y Coordinates

obj_ball.gmx

// If you're trying to give X Y coordinates over a network and you need to flip them on the client side, here's how it can be done.
// global.bx = server sending ball X coordinate
// global.by = server sending ball Y coordinate
// This code should be placed in your ball object's step.

        //show_debug_message("[DEBUG|BALL|REAL] bx:" + string(global.by) + " by:" + string(global.by) + " w/2:" + string(room_width/2) + " h/2:" + string(room_height/2));
        
        //build a fake grid
        fakex = global.bx - (room_width/2);
        fakey = global.by - (room_height/2);
        
        //show_debug_message("[DEBUG|BALL|GRID] fake-x:" + string(fakex) + " fake-y:" + string(fakey));
        
        //flip coordinates
        if (sign(fakex) == -1)
            fakex = abs(fakex);
        else
            fakex = fakex * -1;
        
        if (sign(fakey) == -1)
            fakey = abs(fakey);
        else
            fakey = fakey * -1;
            
        //show_debug_message("[DEBUG|BALL|FLIPPED] fake-x:" + string(fakex) + " fake-y:" + string(fakey));
        
        //remove fake grid
        fakex = fakex + (room_width/2);
        fakey = fakey + (room_height/2);
        
        //show_debug_message("[DEBUG|BALL|RESTORE] fake-x:" + string(fakex) + " fake-y:" + string(fakey));
        
        //move ball to reversed coordinates
        x = fakex;
        y = fakey;