Road pursuit

What it does

Each mission opens with a radio briefing: the criminal, the charge, the car and a frequency. The target starts out of sight, and a DISTANCE counter closes at your speed minus its own. At a fork a flashing arrow shows the way it went, fixed or random, perhaps with a helicopter guiding you, and the other branch is a detour that adds to the distance. When you close in, the dome light and siren come on and the clock is extended or reset.

From the sighting the getaway car is on the road with you, driven by stepTarget. It cruises, sprints when you are on its tail, matches your speed so it cannot simply be overtaken, weaves across the lanes, swerves round traffic, moves across to block you, and pulls over for the arrest. Every ram adds to a segmented damage meter: side hits count for more than rear hits, a higher closing speed adds a bonus, and hitting it from the outside of a bend spins it out. Fill the meter and the arrest follows.

Turbo bursts per mission push the camera back while one burns. If time runs out, a continue countdown starts while the target flees on, with damage cleared or kept as you choose. Barriers and bins smash, tunnel walls spark and slow you, and scoring pays by distance, a rising overtake chain, hits, the clear and time left, cut to a tenth after a continue. Optional rules add a partner's gun with a gunsight lock, a heavy weapon parachuted by a helicopter, a biker gang to bump off the road, a flying target that can only be shot, and a reach-the-goal mission with no target.

Features

• Missions with briefings — criminal, charge, frequency, car, road entry, time, turbos and the fork's rule per mission.
• Out of sight, then on the road — a DISTANCE counter that closes until the sighting, then a target that drives the road with you.
• Forks with an arrow — fixed, random or helicopter-guided, with a detour that costs distance.
• A getaway driver — cruise, sprint, speed matching, weaving, swerving round traffic, blocking and pulling over, with pace by difficulty.
• Ramming damage — a segmented meter, side and rear damage, a closing-speed bonus, cooldown, shove and spin-outs on bends.
• Turbos and a turbo camera — charges per mission and after a continue, with the camera easing back while one burns.
• Continues — a countdown with the target fleeing on, damage cleared or kept, and a cap.
• Scenery to smash — barriers and bins that slow you and score, and tunnel walls that scrape.
• Scoring — distance, an overtake chain, hits and clears by stage, a bonus per second left and an all-clear prize.
• Gun and gang rules — the partner's gun with a lock, a parachuted heavy weapon, a biker gang and flying targets.
• Deterministic — whole 1/60 second steps, snapshot and restore, and Easy, Normal and Arcade difficulty.

Good for

• Police pursuit racers in the style of the 1988 arcade Chase H.Q., five rounds of catching and ramming.
• Pursuit racers with guns in the style of its 1989 sequel S.C.I., with a partner's gunsight, bikers and a helicopter.
• Convoy stops, a slow, wide target with no fork.
• Coastal smuggler chases on a road you drew, one mission with the clock reset at the sighting.
• Car-to-car shooters, with only the gun and no ramming damage.
• Timed escapes, reach-the-goal missions with no target at all.

Make it yours

The config is plain data. Missions set their kind, stage, criminal, briefing, car, road entry, lead, the target's speed out of sight, the fork, time, turbos, gang and heavy weapon. The clock sets the chase time, the extension and whether it adds or resets, the sighting range and warning. The target's driving, the ram rules, turbos, the gun, the heavy weapon, the gang, scoring, continues, smashable objects, tunnel scrapes and the turbo camera are all fields you can change.

The two presets are different games over one block. chaseHQPreset has five rounds on its own road file, ramming only, three five-second turbos, a fork in each stage and a continue that clears the damage. sciPreset has six stages on another road file, the partner's unlimited pistol, a bazooka from the helicopter, a biker gang, a flying target and a final timed run with one turbo and no continue. Both take a difficulty, a seed, a road, timer and turbo settings and a start stage.

A quick look

A chase from the preset, stepped with input and drawn with its turbo camera:

const RP = game.roadPursuit;
const p = RP.createPursuit(RP.chaseHQPreset({ difficulty: "normal" }));
p.start();                                   // the first briefing
p.tick(dt, { throttle, brake, steer, gear: lever, turbo, fire, start }); // presses are latched
for (const e of p.drain()) present(e);       // briefing, go, sighted, warning, turbo, hit, fork, arrest, clear, continue ...
const base = view.camera!;
view.draw(p.scene({ back: base.back, fov: base.fov }));   // the race's scene plus the turbo camera

Works with

• road-racer — required: your car, the road, traffic, crashes and the distance score.
• road-data — required: the road files, whose markers carry the lead and the fork arrows.
• vehicle-handling, pseudo-road and scaled-depth — required: the car's gears and turbo, the road and the field objects every hit is tested on.
• road-view-pseudo3d — draws the scene, the dome light, turbo flames and tunnels.
• road-assault — for a combat rally on a fuel gauge.
• road-combat — for a top-down road shooter.

Good to know

• Before the sighting the target is a counter, not a car, so a detour adds distance rather than being driven; after the sighting it follows the way you go at a fork.
• Two-way traffic, opened bridges, weather and bikers that throw things are not modelled.
• Arrest and briefing pictures are your presenter's; the pack gives the names, charges and tally.
• One player, no high-score entry and no sound, though the events are there for it.
• Damage per hit, the target's speeds and the gun and gang numbers are estimates where no source gives them.