RigidBody2D

The RigidBody2D component allows the entity to collide and interact with other rigid bodies

The physics simulation is simplified. Among others, it assumes mass = 1, which means that acceleration and force are numerically equal.

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import {Vec2} from "../../lib/math.js";
import {clamp} from "../../lib/number.js";
import {Entity} from "../../lib/world.js";
import {Game} from "../game.js";
import {Has} from "../world.js";

export const enum RigidKind {
    Static,
    Dynamic,
}

export interface RigidBody2D {
    Kind: RigidKind;
    Drag: number;
    Bounciness: number;
    Acceleration: Vec2;
    VelocityLinear: Vec2;
    VelocityResolved: Vec2;
    VelocityAngular: number;
    IsGrounded: boolean;
}

Add RigidBody2D to an entity.

kind param: The type of the rigid body (static, dynamic).
bounciness param: Bounciness factor (0 = no bounce, 1 = full bounce).
drag param: Drag factor (0 = no drag, 1 = entity never moves).

export function rigid_body2d(kind: RigidKind, bounciness = 1, drag = 0.001) {
    return (game: Game, entity: Entity) => {
        game.World.Signature[entity] |= Has.RigidBody2D;
        game.World.RigidBody2D[entity] = {
            Kind: kind,
            Drag: clamp(0, 1, drag),
            Bounciness: clamp(0, 1, bounciness),
            Acceleration: [0, 0],
            VelocityLinear: [0, 0],
            VelocityResolved: [0, 0],
            VelocityAngular: 0,
            IsGrounded: false,
        };
    };
}