I''m looking for an algorithm to check for a collision between 2 lines (each line is defined by a set of X,Y cordinates). I''ve already tried one that just checks for a point of intersection but I''m having problems with paralelle lines, slope=0 and other special cases. Is there an easier way? I''m programming it in Object Pascal but if you can show me an example in C it would be just as good.

**Newbie Alert** (that''s me)
Good Question.

I would like to hear an answer also. I''m working on my first "Test Engine". Real simple stuff. My map only has one floor level (Y=-1) and all I do for collision detection is something like Bounding-Sphere-Overlaps-Line = Collide. Right now I can only detect collisions with vertical and horizontal lines. I would like to add some more sophisticated collision detection but there seems to be little documentation on the net or in books.

In my LevelWall type I have 4 floats that define the end points of a line. Since my level only has one floor height (and my character can''t jump) I only need to check for collisions in two dimensions.

In my collision detection algorithm I would like to define a sencond line made from two more points.

The first point defined by the players new x,z.

The second point would be made from the players rotation (rad) and his bounding sphere radius.

Then I would like to check to see if the lines intersect.

A detailed answer with some source (simple for my newbie brain) or a link to something good would not suck at all.

:-)

Unfortunately I need to be working with true lines (not sprites) which can be at any angle. It''s like a 3D engine, but with only 2 dimensions (if that makes sense).

I made a similar program once, and yes: you''ll have to check those special cases. But don''t worry, there aren''t many of them (only two ones you listed).


-Hans