Difference between revisions of "Ray casting"

Revision as of 07:46, 5 January 2009

What is Ray Casting?

Ray casting is a method for calculating Field of Vision where rays are traced from the center of a source square to a select number of destination squares. Squares are marked as visible as the rays pass through them, and walls will block the rays.

There are a few ways to decide where rays are to be cast:

Every potential destination -- This method is very slow, but results in a crude approximation of Shadow casting.
Every square along the perimeter of the area being checked for Field of Vision -- This is faster, but causes an increasing number of artifacts as the radius increases.
A fixed number of rays as regular intervals -- Provides a tweakable knob that trades off between accuracy and speed.

Advantages

Easy to implement
Builds intuitively on Line of Sight algorithms.

Disadvantages

Slow compared to other methods. Even when casting only a few rays, squares close to the source will be visited many times.
Many artifacts, even in common situations

How do I implement it?

What games use it?

Moria

What libraries implement it?

No known libraries implement ray casting.

@@ Line 5: / Line 5: @@
 There are a few ways to decide where rays are to be cast:
-* Every potential destination -- This method is very slow, but results in a crude approximation of [[Shadow cCasting]].
+* Every potential destination -- This method is very slow, but results in a crude approximation of [[Shadow casting]].
 * Every square along the perimeter of the area being checked for [[Field of Vision]] -- This is faster, but causes an increasing number of artifacts as the radius increases.
 * A fixed number of rays as regular intervals -- Provides a tweakable knob that trades off between accuracy and speed.