@awayfl/awayfl-player/lib/Box2D/Dynamics/Contacts/b2PositionSolverManifold.ts

Flash Player emulator for executing SWF files (published for FP versions 6 and up) in javascript

import { b2Vec2, b2Mat22 } from '../../Common/Math';
import { b2ContactConstraint } from '../Contacts';
import { b2Settings } from '../../Common/b2Settings';
import { b2Manifold } from '../../Collision/b2Manifold';

export class b2PositionSolverManifold {
	constructor() {
		this.m_normal = new b2Vec2();
		this.m_separations = new Array<number>(b2Settings.b2_maxManifoldPoints);
		this.m_points = new Array<b2Vec2>(b2Settings.b2_maxManifoldPoints);
		for (let i: number /** int */ = 0; i < b2Settings.b2_maxManifoldPoints; i++) {
			this.m_points[i] = new b2Vec2();
		}
	}

	private static circlePointA: b2Vec2 = new b2Vec2();
	private static circlePointB: b2Vec2 = new b2Vec2();
	public Initialize(cc: b2ContactConstraint): void {
		b2Settings.b2Assert(cc.pointCount > 0);

		let i: number /** int */;
		let clipPointX: number;
		let clipPointY: number;
		let tMat: b2Mat22;
		let tVec: b2Vec2;
		let planePointX: number;
		let planePointY: number;

		switch (cc.type) {
			case b2Manifold.e_circles:
				{
				//var pointA:b2Vec2 = cc.bodyA.GetWorldPoint(cc.localPoint);
					tMat = cc.bodyA.m_xf.R;
					tVec = cc.localPoint;
					const pointAX: number = cc.bodyA.m_xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
					const pointAY: number = cc.bodyA.m_xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
					//var pointB:b2Vec2 = cc.bodyB.GetWorldPoint(cc.points[0].localPoint);
					tMat = cc.bodyB.m_xf.R;
					tVec = cc.points[0].localPoint;
					const pointBX: number = cc.bodyB.m_xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
					const pointBY: number = cc.bodyB.m_xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
					const dX: number = pointBX - pointAX;
					const dY: number = pointBY - pointAY;
					const d2: number = dX * dX + dY * dY;
					if (d2 > Number.MIN_VALUE * Number.MIN_VALUE) {
						const d: number = Math.sqrt(d2);
						this.m_normal.x = dX / d;
						this.m_normal.y = dY / d;
					} else {
						this.m_normal.x = 1.0;
						this.m_normal.y = 0.0;
					}
					this.m_points[0].x = 0.5 * (pointAX + pointBX);
					this.m_points[0].y = 0.5 * (pointAY + pointBY);
					this.m_separations[0] = dX * this.m_normal.x + dY * this.m_normal.y - cc.radius;
				}
				break;
			case b2Manifold.e_faceA:
				{
				//m_normal = cc.bodyA.GetWorldVector(cc.localPlaneNormal);
					tMat = cc.bodyA.m_xf.R;
					tVec = cc.localPlaneNormal;
					this.m_normal.x = tMat.col1.x * tVec.x + tMat.col2.x * tVec.y;
					this.m_normal.y = tMat.col1.y * tVec.x + tMat.col2.y * tVec.y;
					//planePoint = cc.bodyA.GetWorldPoint(cc.localPoint);
					tMat = cc.bodyA.m_xf.R;
					tVec = cc.localPoint;
					planePointX = cc.bodyA.m_xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
					planePointY = cc.bodyA.m_xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);

					tMat = cc.bodyB.m_xf.R;
					for (i = 0; i < cc.pointCount;++i) {
					//clipPoint = cc.bodyB.GetWorldPoint(cc.points[i].localPoint);
						tVec = cc.points[i].localPoint;
						clipPointX = cc.bodyB.m_xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
						clipPointY = cc.bodyB.m_xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
						this.m_separations[i] = (clipPointX - planePointX) * this.m_normal.x + (clipPointY - planePointY) * this.m_normal.y - cc.radius;
						this.m_points[i].x = clipPointX;
						this.m_points[i].y = clipPointY;
					}
				}
				break;
			case b2Manifold.e_faceB:
				{
				//m_normal = cc.bodyB.GetWorldVector(cc.localPlaneNormal);
					tMat = cc.bodyB.m_xf.R;
					tVec = cc.localPlaneNormal;
					this.m_normal.x = tMat.col1.x * tVec.x + tMat.col2.x * tVec.y;
					this.m_normal.y = tMat.col1.y * tVec.x + tMat.col2.y * tVec.y;
					//planePoint = cc.bodyB.GetWorldPoint(cc.localPoint);
					tMat = cc.bodyB.m_xf.R;
					tVec = cc.localPoint;
					planePointX = cc.bodyB.m_xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
					planePointY = cc.bodyB.m_xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);

					tMat = cc.bodyA.m_xf.R;
					for (i = 0; i < cc.pointCount;++i) {
					//clipPoint = cc.bodyA.GetWorldPoint(cc.points[i].localPoint);
						tVec = cc.points[i].localPoint;
						clipPointX = cc.bodyA.m_xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
						clipPointY = cc.bodyA.m_xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
						this.m_separations[i] = (clipPointX - planePointX) * this.m_normal.x + (clipPointY - planePointY) * this.m_normal.y - cc.radius;
						this.m_points[i].Set(clipPointX, clipPointY);
					}

					// Ensure normal points from A to B
					this.m_normal.x *= -1;
					this.m_normal.y *= -1;
				}
				break;
		}
	}

	public m_normal: b2Vec2;
	public m_points: Array<b2Vec2>;
	public m_separations: Array<number>;
}