47 lines
1.8 KiB
TypeScript
47 lines
1.8 KiB
TypeScript
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///<reference path="./Constraint.ts" />
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module es {
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export class AngleConstraint extends Constraint {
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public stiffness: number;
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public angleInRadius: number;
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_particleA: Particle;
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_centerParticle: Particle;
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_particleC: Particle;
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constructor(a: Particle, center: Particle, c: Particle, stiffness: number) {
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super();
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this._particleA = a;
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this._centerParticle = center;
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this._particleC = c;
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this.stiffness = stiffness;
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this.collidesWithColliders = false;
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this.angleInRadius = this.angleBetweenParticles();
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}
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angleBetweenParticles(): number {
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const first = this._particleA.position.sub(this._centerParticle.position);
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const second = this._particleC.position.sub(this._centerParticle.position);
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return Math.atan2(first.x * second.y - first.y * second.x, first.x * second.x + first.y * second.y);
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}
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public solve() {
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const angleBetween = this.angleBetweenParticles();
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let diff = angleBetween - this.angleInRadius;
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if (diff <= -Math.PI)
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diff += 2 * Math.PI;
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else if(diff >= Math.PI)
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diff -= 2 * Math.PI;
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diff *= this.stiffness;
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this._particleA.position = MathHelper.rotateAround2(this._particleA.position, this._centerParticle.position, diff);
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this._particleC.position = MathHelper.rotateAround2(this._particleC.position, this._centerParticle.position, -diff);
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this._centerParticle.position = MathHelper.rotateAround2(this._centerParticle.position, this._particleA.position, diff);
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this._centerParticle.position = MathHelper.rotateAround2(this._centerParticle.position, this._particleC.position, -diff);
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}
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}
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}
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