Hi, I'm trying to create a little raycasting demo thingy where you can only see what you're looking at (mouselook) and vision is obstructed by objects (polygons, although in this code they are all rectangles).

Try the demo (source below), move with asdw, look with the mouse.

You will notice that there are tiny holes in my objects that appear seeming randomly. That's my problem. The line-line collision function is the last function in the program (boolean lineCollide). It is required to return true of the lines ab (ax,ay,bx,by) and cd (cx,cy,dx,dy) collide, and at the end place the collision point in the global variables: col_x and col_y. Does anyone have a better line-line collision function? Also, can you look at my code and tell me if there are any optomizations to be done? (I've never done raycasting before)

Demo and source:
http://www.staronesw.com/raycast2d/