Ridge Racer (the kazuyette/rr-decomp decompilation)

In Ridge Racer's Japanese release (SLPS-00001), car_simulate (func_80019CF4) runs one of four handlers each update by the car's state at offset 0xB4: 0 func_80026E7C, 1 func_80027734, 2 func_80027F60, 3 func_80028294, which the atlas reads as grip, slide, slide recovery, and the start. In state 0 the heading turns a fifth of the way to the steering's target each update, and the car moves only along its heading: the code keeps the forward part of its velocity and drops the sideways part. ridge-racer/grip-state

About: Ridge Racer Drift boost

Cited by: Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), a car in grip (state 0, func_80026E7C) enters a slide (state 1) in two ways. Pressing the accelerator again after lifting off: the code counts the updates the accelerator stays below half (0x80) without a fresh brake press, and on the update the accelerator is pressed again it multiplies the count by the car's speed; a speed above 960 and a product above the car's threshold start the slide. Or a fresh brake press with the accelerator off: the car's sideways velocity times its speed over 64, above the threshold at a speed above 320. The threshold is 14 times a value from the car model's spec table. The product that started the slide becomes the slide's budget (D_801732F0), and the car's yaw rate (D_8012CFE0) is set against its sideways velocity: at least twice it on the accelerator, once on the brake. ridge-racer/slide-entry

About: Ridge Racer Drift boost

The pad's buttons come from a mapping table (D_801D7778), and on a neGcon (id 0x23) the two values are analogue. Field 0x98 (x98), which raises the accelerator kick when it's below 1000, isn't identified. The two numbers the comparisons use, 960 and 320, are in the car's speed units at offset 0xA0.

Cited by: Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), a car in a slide (state 1, func_80027734) turns its heading by its yaw rate over 256 each update, with the yaw rate held within ±0x3600, so at most 54 of the 4,096 units of a full turn (computed: about 4.7°). While the slide's budget is above 0, a term from Phys 0x54 (w54), which the atlas reads as the steering target, adds to the yaw rate and the budget drains each update by 0x40, by the square of the slip angle (heading against direction of travel) over 65,536, by (0x3600 − |yaw rate|)/64, and by 4 times the brake value, with more drained below a speed of 400, below half the car's spec speed, or at a slip under 0x80 with a slow yaw. Once the budget is spent, the yaw rate falls to 15/16 each update, and the slide ends on the first update it starts below 0x1000. ridge-racer/slide-hold

About: Ridge Racer Drift boost

Value: 54 angle units per update (of 4096), the slide's top turn rate

a is the yaw rate's size at the top of the update, so the exit test uses the value before that update's decay. The budget also loses 5000 in func_8001C490 L133 when the car hits something.

Cited by: Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), when a slide ends (func_80027734) the car's direction of travel snaps to its heading and its speed is multiplied by 1 − w²/2²⁰, where w is the slip angle between them folded to at most a quarter turn: a slide that ends at 45° keeps 75% of its speed and one at 90° keeps none (computed). The part taken off keeps moving the car along its old direction in state 2 (func_80027F60), shrinking to 31/32 each update with the leftover angle, and the car returns to grip (state 0) when both reach 0. ridge-racer/slide-exit

About: Ridge Racer Drift boost

Value: 0.75 share of speed kept by a slide ending at 45°

The same branch sets the engine field at Phys 0x58 from the speed and the gear-like field at Phys 0x2A (L70), not read further. In state 2 the steering and the accelerator count from slide-entry carry on, but only state 0 tests for a new slide.

Cited by: Drift boost, Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), car_simulate gives a car in a slide (state 1) an eighth of the engine drive it gets in the other states, and lets its speed fall by 0.4% an update instead of 6%. The slide handler (func_80027734) then scales that drive by (0x200 − w)/0x200 for a slip angle w up to a quarter turn: full drive with no slip, none at 45°, and a pull against the motion beyond (computed). func_80026CA8 adds the drive along the heading, but the slide handler saves the direction of travel before the call and restores it after, so in a slide the drive changes only the speed. ridge-racer/slide-drive

About: Ridge Racer Drift boost

The slide handler restores the direction of travel after func_80026CA8 (L90-L92), so in a slide the drive changes the speed but the turn of the direction comes from the next update's code; the atlas hasn't traced that order further.

Cited by: Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), the player's car starts a race in state 3 (func_80028294). When the grid phase ends at race update 211 and the race begins, func_8001B284 reads the rev counter shown on the tachometer (D_801D7800, the car's revs smoothed and held between 500 and 10000) and sets a counter to 1000 plus its distance below 7500, or 1000 plus six times its distance above 7500, in which case it also halves the engine field at car offset 0xB0. In state 3 the car moves a quarter of what its speed would carry it, and the counter falls each update by the accelerator plus the brake plus 8; at 10 or below the car goes to grip (state 0). With the accelerator held on a digital pad (0x100), revs of 7500 give 4 updates of this, 5000 give 14, and 10000 give 61 (computed). ridge-racer/start-wheelspin

About: Ridge Racer Rocket start

Value: 7500 tachometer revs that make the start shortest

Grid phase is the atlas's reading of race phase 1 (g_race_phase in the repo's notes). The counter keeps falling in later phases only while the car is still in state 3; car_simulate also takes (D_8012CFF0 & 0x1F) << 5 off the revs each update of state 3 in phase 2 (L179-L180). The atlas reads this for the player's car (st_race_main passes D_8007C258); whether the other cars' start goes through it isn't read.

Cited by: Ridge Racer, Rocket start

In Ridge Racer's Japanese release (SLPS-00001), the computer car in entity slot 0 takes its target speed from func_80022C40 during the race (when its field 0x60 is 0 and the game state isn't 0x1A). Unless its mode field 0xAA is 2: when it's on an earlier lap than the player, or on the same lap and behind the player by more than a margin, its target is 1.01 times its field 0x10C; when it's on a later lap, or more than 0x600 ahead on the same lap, its target is 80% of the lower of the usual target and its field 0xF8. The margin is 0x800, or 0x300 times the player's lap count when D_801D35D0 is 0. Between the two the target is left as it was. When D_801D35D0 is 0 and the player is on the last lap, the target is held to field 0xF8. ridge-racer/rival-pace

About: Ridge Racer Rubber-band AI

Fields 0xF8, 0xFC, 0x100 and 0x10C are per-car values the atlas hasn't traced to a table. With mode 2 (0xAA) the target is instead 97% or 87% of the player car's field 0x9C, set at init from its spec (func_8001AA60 L67-L70), by which side of the player it's on. Slot 11 has its own speed rules (func_80022B4C), and every car's target is cut in corners afterward (func_80022F88 L113-L131). The repo doesn't say which car slot 0 is.

Cited by: Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), a lap's time is counted in race updates and converted to milliseconds as if 30 updates were a second: whole seconds times 1000, plus the remaining updates times 100/3. When the player crosses the line from the race direction, the finished lap gets a random 0 to 31 ms added (rand() & 0x1F) before it's compared with the course's best lap. Backing over the line and crossing again doesn't count a lap: the code counts each backward crossing and spends one on the next forward one. The race time is the sum of the laps. ridge-racer/lap-time

The 30-a-second rate is the conversion's; the atlas hasn't measured the race loop's rate. The dither fills the millisecond digits a 30 Hz count can't resolve; it is the atlas's reading, not a comment in the code.

Cited by: Ridge Racer

In Ridge Racer's Japanese release (SLPS-00001), the race clock (D_8012CD20) starts at the course's row of a table (D_8005E90C) times 30 and falls by 1 each race update in phases 2 and 3. Each row also holds a lap bonus and two checkpoint bonuses. Crossing the line to start laps 2 up to the last adds the lap bonus times 30 (another field when D_801733B8 is set). On the course run in its usual direction (D_801733B8 clear), crossing the first checkpoint adds the first checkpoint bonus times 30, and on courses 3 and up a second checkpoint adds the second bonus times 30; backing over a checkpoint and crossing again pays once. While the clock is below 30 the pad is ignored and the car gets no accelerator or brake. Below −59, before the results, the race ends as over. ridge-racer/time-extension

The table values are times 30 to match the 30-a-second lap clock (see lap-time); the atlas hasn't decoded them, so no extension is given in seconds. Phases 5 and 6 are the end states the time-out sets (6 when it happens in phase 2).

Cited by: Ridge Racer