Sunday, August 31, 2008

Collisions

Sorry about the delay in updates.. I have been very busy. The purpose of this post is to discuss car collisions in F-Zero VS.

Car collisions will not work properly until we make a few modifications. When a collision between two cars occurs, both emulator instances involved try to control both car rebound velocities. This conflict results in jagged movement.

The solution to this is to:

a) Make sure that each emulator instance only rebounds its own player during a player-opponent collision by patching occurrences of the code 99 20 0B STA $0B20,Y to NOPs at ROM addresses 00:BDB2, 00:BDD5, 00:BDEF and 00:BDFE.

b) Make the player's rebound speed equal to his current speed instead of the opponents speed (which is what happens in the game) by patching occurrences of the code 9D 20 0B STA $0B20,X to NOPs at ROM addresses 00:BDAE, 00:BDCB and 00:BDE5.