Synchronization of RNG

[Sewer56]

In order to maintain consistency between players, the random number generator will require synchronizing.

Initial Synchronization

Initial synchronization should be performed by hooking the native srand function that has been inlined into the executable. It is available at 0x0059B7BD.

srand() is called on:

• Race load start.
• Race start (after intro cutscene).
• Race restart.

Since srand is only called during initialization, the host should send out a seed to the players every time the function is called and wait for acknowledgements (effectively freeze the game). Players should wait for an acknowledgement from the host.

Constant Synchronization

While initial synchronization should maintain perfect synchronization in theory; in practice there are still edge cases such as a client disconnecting, grabbing an item box and reconnecting.

Other cases include RNG triggering events that may not be hooked by the user.
In order to enforce a consistent RNG for those edge cases, the client's seeds should simply force synchronize with the host in a non-blocking way.

During gameplay, after the host executes the rand function, the host should send a copy of the new seed using the reliable channel. Clients will apply this new seed asynchronously.

rand() is called on:

• Periodically on a timer.
• On item pickup.
• On other similar conditions.

Address of rand: 0x0059B7CA

[Sewer56]

Implemented, however currently desyncs due to off-screen objects seeding RNG for one player but not the other.