doom experiments

For some reason the effect of picking up an item is determined by the 4-character prefix of the sprite name, not its thing id. With this you can have multiple versions of a pickup with different sprites:





Here's a minimal example that replaces the invisibility sphere with a differently colored soul sphere:

http://rbkz.net/exp/soul_color.wad

(shoutout to GrainOfSalt, who clued me into this particular effect)