108 lines
3.4 KiB
TypeScript
108 lines
3.4 KiB
TypeScript
import { System, SystemNames } from '.';
|
||
import {
|
||
BoundingBox,
|
||
ComponentNames,
|
||
Forces,
|
||
Gravity,
|
||
Velocity,
|
||
Mass,
|
||
Jump,
|
||
Moment,
|
||
Control
|
||
} from '../components';
|
||
import { PhysicsConstants } from '../config';
|
||
import type { Force2D, Velocity2D } from '../interfaces';
|
||
import { Game } from '../Game';
|
||
|
||
export class Physics extends System {
|
||
constructor() {
|
||
super(SystemNames.Physics);
|
||
}
|
||
|
||
public update(dt: number, game: Game): void {
|
||
game.forEachEntityWithComponent(ComponentNames.Forces, (entity) => {
|
||
const mass = entity.getComponent<Mass>(ComponentNames.Mass).mass;
|
||
const forces = entity.getComponent<Forces>(ComponentNames.Forces).forces;
|
||
const velocity = entity.getComponent<Velocity>(
|
||
ComponentNames.Velocity
|
||
).velocity;
|
||
const inertia = entity.getComponent<Moment>(
|
||
ComponentNames.Moment
|
||
).inertia;
|
||
|
||
// F_g = mg, applied only until terminal velocity is reached
|
||
if (entity.hasComponent(ComponentNames.Gravity)) {
|
||
const gravity = entity.getComponent<Gravity>(ComponentNames.Gravity);
|
||
if (velocity.dCartesian.dy <= gravity.terminalVelocity) {
|
||
forces.push({
|
||
fCartesian: {
|
||
fy: mass * PhysicsConstants.GRAVITY,
|
||
fx: 0
|
||
},
|
||
torque: 0
|
||
});
|
||
}
|
||
}
|
||
|
||
// ma = Σ(F), Iα = Σ(T)
|
||
const sumOfForces = forces.reduce(
|
||
(accum: Force2D, { fCartesian, torque }: Force2D) => ({
|
||
fCartesian: {
|
||
fx: accum.fCartesian.fx + (fCartesian?.fx ?? 0),
|
||
fy: accum.fCartesian.fy + (fCartesian?.fy ?? 0)
|
||
},
|
||
torque: accum.torque + (torque ?? 0)
|
||
}),
|
||
{ fCartesian: { fx: 0, fy: 0 }, torque: 0 }
|
||
);
|
||
|
||
// integrate accelerations
|
||
const [ddy, ddx] = [
|
||
sumOfForces.fCartesian.fy,
|
||
sumOfForces.fCartesian.fx
|
||
].map((x) => x / mass);
|
||
velocity.dCartesian.dx += ddx * dt;
|
||
velocity.dCartesian.dy += ddy * dt;
|
||
velocity.dTheta += (sumOfForces.torque * dt) / inertia;
|
||
|
||
// clear the forces
|
||
entity.getComponent<Forces>(ComponentNames.Forces).forces = [];
|
||
|
||
// maybe we fell off the floor
|
||
if (ddy > 0 && entity.hasComponent(ComponentNames.Jump)) {
|
||
entity.getComponent<Jump>(ComponentNames.Jump).canJump = false;
|
||
}
|
||
});
|
||
|
||
game.forEachEntityWithComponent(ComponentNames.Velocity, (entity) => {
|
||
const velocityComponent: Velocity = new Velocity();
|
||
const control = entity.getComponent<Control>(ComponentNames.Control);
|
||
|
||
velocityComponent.add(
|
||
entity.getComponent<Velocity>(ComponentNames.Velocity).velocity
|
||
);
|
||
if (control) {
|
||
velocityComponent.add(control.controlVelocityComponent.velocity);
|
||
}
|
||
|
||
const boundingBox = entity.getComponent<BoundingBox>(
|
||
ComponentNames.BoundingBox
|
||
);
|
||
|
||
// integrate velocity
|
||
boundingBox.center.x += velocityComponent.velocity.dCartesian.dx * dt;
|
||
boundingBox.center.y += velocityComponent.velocity.dCartesian.dy * dt;
|
||
boundingBox.rotation += velocityComponent.velocity.dTheta * dt;
|
||
boundingBox.rotation =
|
||
(boundingBox.rotation < 0
|
||
? 360 + boundingBox.rotation
|
||
: boundingBox.rotation) % 360;
|
||
|
||
// clear the control velocity
|
||
if (control && control.isControllable) {
|
||
control.controlVelocityComponent = new Velocity();
|
||
}
|
||
});
|
||
}
|
||
}
|