Mario Kart 64 (the n64decomp decompilation, n64decomp/mk64)

In the US version of Mario Kart 64, gen_random_item picks an item as one byte from a 100-byte row of a table, the row for the driver's current place. In Grand Prix, human players read common_grand_prix_human_item_curve and CPU drivers common_grand_prix_cpu_item_curve, and that branch reads no player count. Versus picks one of three tables by the number of players (two, three, or four), and Battle reads one row whatever the place. The slot is a random number from 0 to 100 (random_int(100)) plus the previous slot, a counter that held A, B, and R buttons advance, and the race frame counter, taken mod 100. mk64/item-roulette

About: Mario Kart 64 Item distribution

Value: 100 slots per place

The tables are game data the build extracts from the ROM, so their bytes aren't in the repo and the chance of each item per place isn't read here. The decompilers' extraction map (yamls/us/common_data.yml, outside the fetched paths) gives the human Grand Prix table 800 bytes, eight rows of 100. random_int(100) can return 100 only when random_u16 returns 65535; the mod keeps the slot below 100 either way.

Cited by: Diddy Kong Racing, Item distribution, Mario Kart 64, Mario Kart: Double Dash!!

In the US version of Mario Kart 64, while a kart drifts on the ground, holding the stick at least 10 of its 53 steps toward the outside of the turn counts up driftStateCounter. Letting the stick back after 18 to 99 counts raises driftState by one, up to 3, and sets the count to 10, so each later step takes 8 more counts (computed); letting it back before 10 counts, or at 100 or more, resets both to 0. When a human player's drift ends with driftState at 2 or more, the kart gets MINI_TURBO_EFFECT for 31 player updates (computed), during which a term in its forward force moves toward 580 by a fifth of the gap each update. mk64/mini-turbo

About: Mario Kart 64 Drift boost

{
 "steps-to-boost": 2,
 "first-step": 18,
 "later-steps": 8,
 "overheld": 100,
 "boost-updates": 31,
 "boost-term": 580
}

The counter steps once per call of update_drift_state_counter, one per player update; how updates map to displayed frames isn't read. "Toward the outside" follows the sign of the DRIFT_OUTSIDE_EFFECT tests in the same branch: a drift with unk_0C0 positive counts steerPosition at -10 or below, and marks -40 or below as the outside. The 31 is computed: the update that starts the boost sets unk_23A to 0, and the 31st after clears the effect. driftState also goes into the drift's particles (src/code_80057C60.c#L2865-L2883).

Cited by: Drift boost, Mario Kart 64

In the US version of Mario Kart 64, in Grand Prix and Versus the engine class sets each kart's top speed from gTopSpeedTable when it spawns: 290 at 50cc, 310 at 100cc, and 320 at 150cc for Mario, Luigi, Donkey Kong, Wario, and Bowser, and 4 more for Yoshi, Toad, and Peach. Extra uses the 100cc numbers, Time Trials always reads the 100cc row, and Battle gives every driver 245. mk64/top-speed

About: Mario Kart 64 Engine class

{
 "50cc": [
  290,
  294
 ],
 "100cc": [
  310,
  314
 ],
 "150cc": [
  320,
  324
 ],
 "extra": [
  310,
  314
 ],
 "battle": [
  245,
  245
 ]
}

topSpeed scales the acceleration steps (in player_accelerate_during_start_sequence each tenth of it has its own rate, src/player_controller.c#L3639-L3667); the unit is the game's own. The same spawn switch reads two more per-class tables, unnamed (D_800E2400, D_800E24B4), and a third (D_800E2568) that also favors the three light drivers.

Cited by: Engine class, Mario Kart 64

In the US version of Mario Kart 64, CPU_FAST_EFFECT, which the decompilers comment as the "CPU Rubberbanding flag", raises a CPU driver's forward force: while it's set, a term in that force moves toward 380 by half the gap each update, and once it's cleared the term falls toward 0 by a tenth of the gap. regulate_cpu_speed sets the flag on a CPU driver below its target speed when the pacing check func_800088D8 returns true, and clears it otherwise. mk64/rubber-band

About: Mario Kart 64 Rubber-band AI

Value: 380

The statement leaves out when func_800088D8 returns true, because its inputs are mostly unnamed. As read: Time Trials and human players always pass; a CPU driver in first place fails when its lead over the best-placed human, in path points, passes a per-course allowance times the class index plus one, once its speed reads 20 or more (src/cpu_vehicles_camera_path.c#L1016-L1040); other places pass when the gap to the driver in D_80163344[0] exceeds a per-place allowance from a course table (L1043-L1089). Other branches of regulate_cpu_speed set the flag too (cpu_speed_control.inc.c#L172-L176 and L188-L190, and func_80007D04). A human mini-turbo drives the same unk_0E8 term toward 580 (mk64/mini-turbo).

Cited by: Mario Kart 64, Rubber-band AI

In the US version of Mario Kart 64, the start boost's window opens when Lakitu's countdown finishes the animation after its second light sound, before the green-light sound. A press of A that begins within 8 counts of the race frame counter from the first update the window is open (20 in Time Trials) sets START_BOOST_TRIGGER, and letting go of A before the start clears it. The trigger gives the kart the Mushroom's effect and the same boost timer, 80. Once the window is open, a kart that revs to 90% of its top speed without the trigger gets START_SPINOUT_TRIGGER, the spin-out for holding the gas. mk64/start-boost

About: Mario Kart 64 Rocket start

{
 "window": 8,
 "window-time-trials": 20,
 "spinout-at": 0.9,
 "boost-timer": 80
}

THROTTLE is set at the end of each accelerating update and cleared by each decelerating one, so the test needs A up on the update before the press. The window counts the race frame counter, which steps once per unpaused call of func_80059AC8; its rate against displayed frames, and the countdown's timing in seconds, aren't read. The flag and the per-player first frame (D_801656F0, D_801652E0) are unnamed in the decompilation. The demo sets the trigger directly for some drivers (src/cpu_vehicles_camera_path.c#L2224-L2229).

Cited by: Diddy Kong Racing, Mario Kart 64, Rocket start