@awayfl/awayfl-player
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Flash Player emulator for executing SWF files (published for FP versions 6 and up) in javascript
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text/typescript
/*
* Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
import { b2Shape } from './b2Shape';
import { b2XForm, b2Vec2, b2Mat22, b2Math } from '../../Common/Math';
import { b2Settings } from '../../Common/b2Settings';
import { b2AABB } from '../b2AABB';
import { b2OBB } from '../b2OBB';
import { b2ShapeDef } from './b2ShapeDef';
import { b2PolygonDef } from './b2PolygonDef';
import { b2Segment } from '../b2Segment';
import { b2MassData } from './b2MassData';
/// Convex polygon. The vertices must be in CCW order for a right-handed
/// coordinate system with the z-axis coming out of the screen.
export class b2PolygonShape extends b2Shape {
/// @see b2Shape::TestPoint
public TestPoint(xf: b2XForm, p: b2Vec2): boolean {
let tVec: b2Vec2;
//b2Vec2 pLocal = b2MulT(xf.R, p - xf.position);
const tMat: b2Mat22 = xf.R;
let tX: number = p.x - xf.position.x;
let tY: number = p.y - xf.position.y;
const pLocalX: number = (tX * tMat.col1.x + tY * tMat.col1.y);
const pLocalY: number = (tX * tMat.col2.x + tY * tMat.col2.y);
for (let i: number /** int */ = 0; i < this.m_vertexCount; ++i) {
//float32 dot = b2Dot(m_normals[i], pLocal - m_vertices[i]);
tVec = this.m_vertices[i];
tX = pLocalX - tVec.x;
tY = pLocalY - tVec.y;
tVec = this.m_normals[i];
const dot: number = (tVec.x * tX + tVec.y * tY);
if (dot > 0.0) {
return false;
}
}
return true;
}
/// @see b2Shape::TestSegment
public TestSegment(xf: b2XForm,
lambda: number[], // float ptr
normal: b2Vec2, // ptr
segment: b2Segment,
maxLambda: number
): number {
let lower: number = 0.0;
let upper: number = maxLambda;
let tX: number;
let tY: number;
let tMat: b2Mat22;
let tVec: b2Vec2;
//b2Vec2 p1 = b2MulT(xf.R, segment.p1 - xf.position);
tX = segment.p1.x - xf.position.x;
tY = segment.p1.y - xf.position.y;
tMat = xf.R;
const p1X: number = (tX * tMat.col1.x + tY * tMat.col1.y);
const p1Y: number = (tX * tMat.col2.x + tY * tMat.col2.y);
//b2Vec2 p2 = b2MulT(xf.R, segment.p2 - xf.position);
tX = segment.p2.x - xf.position.x;
tY = segment.p2.y - xf.position.y;
tMat = xf.R;
const p2X: number = (tX * tMat.col1.x + tY * tMat.col1.y);
const p2Y: number = (tX * tMat.col2.x + tY * tMat.col2.y);
//b2Vec2 d = p2 - p1;
const dX: number = p2X - p1X;
const dY: number = p2Y - p1Y;
let index: number /** int */ = -1;
for (let i: number /** int */ = 0; i < this.m_vertexCount; ++i) {
// p = p1 + a * d
// dot(normal, p - v) = 0
// dot(normal, p1 - v) + a * dot(normal, d) = 0
//float32 numerator = b2Dot(this.m_normals[i], this.m_vertices[i] - p1);
tVec = this.m_vertices[i];
tX = tVec.x - p1X;
tY = tVec.y - p1Y;
tVec = this.m_normals[i];
const numerator: number = (tVec.x * tX + tVec.y * tY);
//float32 denominator = b2Dot(this.m_normals[i], d);
const denominator: number = (tVec.x * dX + tVec.y * dY);
// Note: we want this predicate without division:
// lower < numerator / denominator, where denominator < 0
// Since denominator < 0, we have to flip the inequality:
// lower < numerator / denominator <==> denominator * lower > numerator.
if(denominator == 0.0) {
if(numerator < 0.0)
{
return b2Shape.e_missCollide;
}
} else {
if (denominator < 0.0 && numerator < lower * denominator) {
// Increase lower.
// The segment enters this half-space.
lower = numerator / denominator;
index = i;
} else if (denominator > 0.0 && numerator < upper * denominator) {
// Decrease upper.
// The segment exits this half-space.
upper = numerator / denominator;
}
if (upper < lower) {
return b2Shape.e_missCollide;
}
}
}
//b2Settings.b2Assert(0.0 <= lower && lower <= maxLambda);
if (index >= 0) {
//*lambda = lower;
lambda[0] = lower;
//*normal = b2Mul(xf.R, this.m_normals[index]);
tMat = xf.R;
tVec = this.m_normals[index];
normal.x = (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
normal.y = (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
return b2Shape.e_hitCollide;
}
lambda[0] = 0;
return b2Shape.e_startsInsideCollide;
}
/// @see b2Shape::ComputeAABB
//
private static s_computeMat: b2Mat22 = new b2Mat22();
//
public ComputeAABB(aabb: b2AABB, xf: b2XForm): void {
let tMat: b2Mat22;
let tVec: b2Vec2;
const R: b2Mat22 = b2PolygonShape.s_computeMat;
//b2Mat22 R = b2Mul(xf.R, this.m_obb.R);
tMat = xf.R;
tVec = this.m_obb.R.col1;
//R.col1 = b2MulMV(A, B.col1)
R.col1.x = (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
R.col1.y = (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
//
tVec = this.m_obb.R.col2;
//R.col1 = b2MulMV(A, B.col2)
R.col2.x = (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
R.col2.y = (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
//b2Mat22 absR = b2Abs(R);
R.Abs();
const absR: b2Mat22 = R;
//b2Vec2 h = b2Mul(absR, this.m_obb.extents);
tVec = this.m_obb.extents;
const hX: number = (absR.col1.x * tVec.x + absR.col2.x * tVec.y);
const hY: number = (absR.col1.y * tVec.x + absR.col2.y * tVec.y);
//b2Vec2 position = xf.position + b2Mul(xf.R, this.m_obb.center);
tMat = xf.R;
tVec = this.m_obb.center;
const positionX: number = xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
const positionY: number = xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
//aabb->lowerBound = position - h;
aabb.lowerBound.Set(positionX - hX, positionY - hY);
//aabb->upperBound = position + h;
aabb.upperBound.Set(positionX + hX, positionY + hY);
}
/// @see b2Shape::ComputeSweptAABB
//
private static s_sweptAABB1: b2AABB = new b2AABB();
private static s_sweptAABB2: b2AABB = new b2AABB();
//
public ComputeSweptAABB(aabb: b2AABB,
transform1: b2XForm,
transform2: b2XForm): void {
//b2AABB aabb1, aabb2;
const aabb1: b2AABB = b2PolygonShape.s_sweptAABB1;
const aabb2: b2AABB = b2PolygonShape.s_sweptAABB2;
this.ComputeAABB(aabb1, transform1);
this.ComputeAABB(aabb2, transform2);
//aabb.lowerBound = b2Min(aabb1.lowerBound, aabb2.lowerBound);
aabb.lowerBound.Set((aabb1.lowerBound.x < aabb2.lowerBound.x ? aabb1.lowerBound.x : aabb2.lowerBound.x),
(aabb1.lowerBound.y < aabb2.lowerBound.y ? aabb1.lowerBound.y : aabb2.lowerBound.y));
//aabb.upperBound = b2Max(aabb1.upperBound, aabb2.upperBound);
aabb.upperBound.Set((aabb1.upperBound.x > aabb2.upperBound.x ? aabb1.upperBound.x : aabb2.upperBound.x),
(aabb1.upperBound.y > aabb2.upperBound.y ? aabb1.upperBound.y : aabb2.upperBound.y));
}
/// @see b2Shape::ComputeMass
//
//
public ComputeMass(massData: b2MassData): void {
// Polygon mass, centroid, and inertia.
// Let rho be the polygon density in mass per unit area.
// Then:
// mass = rho * int(dA)
// centroid.x = (1/mass) * rho * int(x * dA)
// centroid.y = (1/mass) * rho * int(y * dA)
// I = rho * int((x*x + y*y) * dA)
//
// We can compute these integrals by summing all the integrals
// for each triangle of the polygon. To evaluate the integral
// for a single triangle, we make a change of variables to
// the (u,v) coordinates of the triangle:
// x = x0 + e1x * u + e2x * v
// y = y0 + e1y * u + e2y * v
// where 0 <= u && 0 <= v && u + v <= 1.
//
// We integrate u from [0,1-v] and then v from [0,1].
// We also need to use the Jacobian of the transformation:
// D = cross(e1, e2)
//
// Simplification: triangle centroid = (1/3) * (p1 + p2 + p3)
//
// The rest of the derivation is handled by computer algebra.
//b2Settings.b2Assert(this.m_vertexCount >= 3);
//b2Vec2 center; center.Set(0.0f, 0.0f);
let centerX: number = 0.0;
let centerY: number = 0.0;
let area: number = 0.0;
let I: number = 0.0;
// pRef is the reference point for forming triangles.
// It's location doesn't change the result (except for rounding error).
//b2Vec2 pRef(0.0f, 0.0f);
const p1X: number = 0.0;
const p1Y: number = 0.0;
/*#if 0
// This code would put the reference point inside the polygon.
for (int32 i = 0; i < this.m_vertexCount; ++i)
{
pRef += this.m_vertices[i];
}
pRef *= 1.0f / count;
#endif*/
const k_inv3: number = 1.0 / 3.0;
for (let i: number /** int */ = 0; i < this.m_vertexCount; ++i) {
// Triangle vertices.
//b2Vec2 p1 = pRef;
//
//b2Vec2 p2 = this.m_vertices[i];
const p2: b2Vec2 = this.m_vertices[i];
//b2Vec2 p3 = i + 1 < this.m_vertexCount ? this.m_vertices[i+1] : this.m_vertices[0];
const p3: b2Vec2 = i + 1 < this.m_vertexCount ? this.m_vertices[i + 1] : this.m_vertices[0];
//b2Vec2 e1 = p2 - p1;
const e1X: number = p2.x - p1X;
const e1Y: number = p2.y - p1Y;
//b2Vec2 e2 = p3 - p1;
const e2X: number = p3.x - p1X;
const e2Y: number = p3.y - p1Y;
//float32 D = b2Cross(e1, e2);
const D: number = e1X * e2Y - e1Y * e2X;
//float32 triangleArea = 0.5f * D;
const triangleArea: number = 0.5 * D;
area += triangleArea;
// Area weighted centroid
//center += triangleArea * k_inv3 * (p1 + p2 + p3);
centerX += triangleArea * k_inv3 * (p1X + p2.x + p3.x);
centerY += triangleArea * k_inv3 * (p1Y + p2.y + p3.y);
//float32 px = p1.x, py = p1.y;
const px: number = p1X;
const py: number = p1Y;
//float32 ex1 = e1.x, ey1 = e1.y;
const ex1: number = e1X;
const ey1: number = e1Y;
//float32 ex2 = e2.x, ey2 = e2.y;
const ex2: number = e2X;
const ey2: number = e2Y;
//float32 intx2 = k_inv3 * (0.25f * (ex1*ex1 + ex2*ex1 + ex2*ex2) + (px*ex1 + px*ex2)) + 0.5f*px*px;
const intx2: number = k_inv3 * (0.25 * (ex1 * ex1 + ex2 * ex1 + ex2 * ex2) + (px * ex1 + px * ex2)) + 0.5 * px * px;
//float32 inty2 = k_inv3 * (0.25f * (ey1*ey1 + ey2*ey1 + ey2*ey2) + (py*ey1 + py*ey2)) + 0.5f*py*py;
const inty2: number = k_inv3 * (0.25 * (ey1 * ey1 + ey2 * ey1 + ey2 * ey2) + (py * ey1 + py * ey2)) + 0.5 * py * py;
I += D * (intx2 + inty2);
}
// Total mass
massData.mass = this.m_density * area;
// Center of mass
//b2Settings.b2Assert(area > Number.MIN_VALUE);
//center *= 1.0f / area;
centerX *= 1.0 / area;
centerY *= 1.0 / area;
//massData->center = center;
massData.center.Set(centerX, centerY);
// Inertia tensor relative to the local origin.
massData.I = this.m_density * I;
}
/// Get the oriented bounding box relative to the parent body.
public GetOBB(): b2OBB {
return this.m_obb;
}
/// Get local centroid relative to the parent body.
public GetCentroid(): b2Vec2 {
return this.m_centroid;
}
/// Get the vertex count.
public GetVertexCount(): number /** int */{
return this.m_vertexCount;
}
/// Get the vertices in local coordinates.
public GetVertices(): b2Vec2[] {
return this.m_vertices;
}
/// Get the core vertices in local coordinates. These vertices
/// represent a smaller polygon that is used for time of impact
/// computations.
public GetCoreVertices(): b2Vec2[] {
return this.m_coreVertices;
}
/// Get the edge normal vectors. There is one for each vertex.
public GetNormals(): b2Vec2[] {
return this.m_normals;
}
/// Get the first vertex and apply the supplied transform.
public GetFirstVertex(xf: b2XForm): b2Vec2 {
return b2Math.b2MulX(xf, this.m_coreVertices[0]);
}
/// Get the centroid and apply the supplied transform.
public Centroid(xf: b2XForm): b2Vec2 {
return b2Math.b2MulX(xf, this.m_centroid);
}
/// Get the support point in the given world direction.
/// Use the supplied transform.
private s_supportVec: b2Vec2 = new b2Vec2();
public Support(xf: b2XForm, dX: number, dY: number): b2Vec2 {
let tVec: b2Vec2;
let tMat: b2Mat22;
//b2Vec2 dLocal = b2MulT(xf.R, d);
tMat = xf.R;
const dLocalX: number = (dX * tMat.col1.x + dY * tMat.col1.y);
const dLocalY: number = (dX * tMat.col2.x + dY * tMat.col2.y);
let bestIndex: number /** int */ = 0;
//var bestValue:number = b2Dot(this.m_coreVertices[0], dLocal);
tVec = this.m_coreVertices[0];
let bestValue: number = (tVec.x * dLocalX + tVec.y * dLocalY);
for (let i: number /** int */ = 1; i < this.m_vertexCount; ++i) {
//var value:number = b2Dot(this.m_coreVertices[i], dLocal);
tVec = this.m_coreVertices[i];
const value: number = (tVec.x * dLocalX + tVec.y * dLocalY);
if (value > bestValue) {
bestIndex = i;
bestValue = value;
}
}
//return b2Math.b2MulX(xf, this.m_coreVertices[bestIndex]);
tMat = xf.R;
tVec = this.m_coreVertices[bestIndex];
this.s_supportVec.x = xf.position.x + (tMat.col1.x * tVec.x + tMat.col2.x * tVec.y);
this.s_supportVec.y = xf.position.y + (tMat.col1.y * tVec.x + tMat.col2.y * tVec.y);
return this.s_supportVec;
}
//--------------- Internals Below -------------------
constructor(def: b2ShapeDef) {
super(def);
//b2Settings.b2Assert(def.type == e_polygonShape);
this.m_type = b2PolygonShape.e_polygonShape;
const poly: b2PolygonDef = def as b2PolygonDef;
// Get the vertices transformed into the body frame.
this.m_vertexCount = poly.vertexCount;
//b2Settings.b2Assert(3 <= this.m_vertexCount && this.m_vertexCount <= b2_maxPolygonVertices);
let i: number /** int */ = 0;
let i1: number /** int */ = i;
let i2: number /** int */ = i;
// AWAY fix, beacuse it can be ASArray
let v_arr: Array<b2Vec2> = poly.vertices;
if (!v_arr) {
console.error('[B2D] Try create polygon shape from def', def);
return this;
}
if (typeof v_arr['traits'] !== 'undefined') {
v_arr = <any>v_arr['value'] as Array<b2Vec2>;
}
// Copy vertices.
for (i = 0; i < this.m_vertexCount; ++i) {
this.m_vertices[i] = v_arr[i].Copy();
}
// Compute normals. Ensure the edges have non-zero length.
for (i = 0; i < this.m_vertexCount; ++i) {
i1 = i;
i2 = i + 1 < this.m_vertexCount ? i + 1 : 0;
//b2Vec2 edge = this.m_vertices[i2] - this.m_vertices[i1];
const edgeX: number = this.m_vertices[i2].x - this.m_vertices[i1].x;
const edgeY: number = this.m_vertices[i2].y - this.m_vertices[i1].y;
//b2Settings.b2Assert(edge.LengthSquared() > Number.MIN_VALUE * Number.MIN_VALUE);
//this.m_normals[i] = b2Cross(edge, 1.0f); ^^
const len: number = Math.sqrt(edgeX * edgeX + edgeY * edgeY);
//this.m_normals[i].Normalize();
this.m_normals[i] = new b2Vec2(edgeY / len, -edgeX / len);
}
/*#ifdef _DEBUG
// Ensure the polygon is convex.
for (int32 i = 0; i < this.m_vertexCount; ++i)
{
for (int32 j = 0; j < this.m_vertexCount; ++j)
{
// Don't check vertices on the current edge.
if (j == i || j == (i + 1) % this.m_vertexCount)
{
continue;
}
// Your polygon is non-convex (it has an indentation).
// Or your polygon is too skinny.
float32 s = b2Dot(this.m_normals[i], this.m_vertices[j] - this.m_vertices[i]);
b2Assert(s < -b2_linearSlop);
}
}
// Ensure the polygon is counter-clockwise.
for (i = 1; i < this.m_vertexCount; ++i)
{
var cross:number = b2Math.b2CrossVV(this.m_normals[int(i-1)], this.m_normals[i]);
// Keep asinf happy.
cross = b2Math.b2Clamp(cross, -1.0, 1.0);
// You have consecutive edges that are almost parallel on your polygon.
var angle:number = Math.asin(cross);
//b2Assert(angle > b2_angularSlop);
trace(angle > b2Settings.b2_angularSlop);
}
#endif*/
// Compute the polygon centroid.
this.m_centroid = b2PolygonShape.ComputeCentroid(v_arr, poly.vertexCount);
// Compute the oriented bounding box.
b2PolygonShape.ComputeOBB(this.m_obb, this.m_vertices, this.m_vertexCount);
// Create core polygon shape by shifting edges inward.
// Also compute the min/max radius for CCD.
for (i = 0; i < this.m_vertexCount; ++i) {
i1 = i - 1 >= 0 ? i - 1 : this.m_vertexCount - 1;
i2 = i;
//b2Vec2 n1 = this.m_normals[i1];
const n1X: number = this.m_normals[i1].x;
const n1Y: number = this.m_normals[i1].y;
//b2Vec2 n2 = this.m_normals[i2];
const n2X: number = this.m_normals[i2].x;
const n2Y: number = this.m_normals[i2].y;
//b2Vec2 v = this.m_vertices[i] - this.m_centroid;
const vX: number = this.m_vertices[i].x - this.m_centroid.x;
const vY: number = this.m_vertices[i].y - this.m_centroid.y;
//b2Vec2 d;
const dX: number = (n1X * vX + n1Y * vY) - b2Settings.b2_toiSlop;
const dY: number = (n2X * vX + n2Y * vY) - b2Settings.b2_toiSlop;
// Shifting the edge inward by b2_toiSlop should
// not cause the plane to pass the centroid.
// Your shape has a radius/extent less than b2_toiSlop.
//b2Settings.b2Assert(d.x >= 0.0);
//b2Settings.b2Assert(d.y >= 0.0);
//var A:b2Mat22;
//A.col1.x = n1.x; A.col2.x = n1.y;
//A.col1.y = n2.x; A.col2.y = n2.y;
//this.m_coreVertices[i] = A.Solve(d) + this.m_centroid;
//float32 det = a11 * a22 - a12 * a21;
const det: number = 1.0 / (n1X * n2Y - n1Y * n2X);
//det = 1.0 / det;
this.m_coreVertices[i] = new b2Vec2(det * (n2Y * dX - n1Y * dY) + this.m_centroid.x,
det * (n1X * dY - n2X * dX) + this.m_centroid.y);
}
}
public UpdateSweepRadius(center: b2Vec2): void {
let tVec: b2Vec2;
// Update the sweep radius (maximum radius) as measured from
// a local center point.
this.m_sweepRadius = 0.0;
for (let i: number /** int */ = 0; i < this.m_vertexCount; ++i) {
//b2Vec2 d = this.m_coreVertices[i] - center;
tVec = this.m_coreVertices[i];
let dX: number = tVec.x - center.x;
const dY: number = tVec.y - center.y;
dX = Math.sqrt(dX * dX + dY * dY);
//this.m_sweepRadius = b2Max(this.m_sweepRadius, d.Length());
if (dX > this.m_sweepRadius) this.m_sweepRadius = dX;
}
}
// Local position of the polygon centroid.
public m_centroid: b2Vec2;
public m_obb: b2OBB = new b2OBB();
public m_vertices: b2Vec2[] = new Array(b2Settings.b2_maxPolygonVertices);
public m_normals: b2Vec2[] = new Array(b2Settings.b2_maxPolygonVertices);
public m_coreVertices: b2Vec2[] = new Array(b2Settings.b2_maxPolygonVertices);
public m_vertexCount: number /** int */;
public static ComputeCentroid(vs: b2Vec2[], count: number /** int */): b2Vec2 {
//b2Settings.b2Assert(count >= 3);
//b2Vec2 c; c.Set(0.0f, 0.0f);
const c: b2Vec2 = new b2Vec2();
let area: number = 0.0;
// pRef is the reference point for forming triangles.
// It's location doesn't change the result (except for rounding error).
//b2Vec2 pRef(0.0f, 0.0f);
const p1X: number = 0.0;
const p1Y: number = 0.0;
/*#if 0
// This code would put the reference point inside the polygon.
for (int32 i = 0; i < count; ++i)
{
pRef += vs[i];
}
pRef *= 1.0f / count;
#endif*/
const inv3: number = 1.0 / 3.0;
for (let i: number /** int */ = 0; i < count; ++i) {
// Triangle vertices.
//b2Vec2 p1 = pRef;
// 0.0, 0.0
//b2Vec2 p2 = vs[i];
const p2: b2Vec2 = vs[i];
//b2Vec2 p3 = i + 1 < count ? vs[i+1] : vs[0];
const p3: b2Vec2 = i + 1 < count ? vs[i + 1] : vs[0];
//b2Vec2 e1 = p2 - p1;
const e1X: number = p2.x - p1X;
const e1Y: number = p2.y - p1Y;
//b2Vec2 e2 = p3 - p1;
const e2X: number = p3.x - p1X;
const e2Y: number = p3.y - p1Y;
//float32 D = b2Cross(e1, e2);
const D: number = (e1X * e2Y - e1Y * e2X);
//float32 triangleArea = 0.5f * D;
const triangleArea: number = 0.5 * D;
area += triangleArea;
// Area weighted centroid
//c += triangleArea * inv3 * (p1 + p2 + p3);
c.x += triangleArea * inv3 * (p1X + p2.x + p3.x);
c.y += triangleArea * inv3 * (p1Y + p2.y + p3.y);
}
// Centroid
//beSettings.b2Assert(area > Number.MIN_VALUE);
//c *= 1.0 / area;
c.x *= 1.0 / area;
c.y *= 1.0 / area;
return c;
}
// http://www.geometrictools.com/Documentation/MinimumAreaRectangle.pdf
public static ComputeOBB(obb: b2OBB, vs: b2Vec2[], count: number /** int */): void {
let i: number /** int */;
//b2Settings.b2Assert(count <= b2Settings.b2_maxPolygonVertices);
const p: b2Vec2[] = new Array(b2Settings.b2_maxPolygonVertices + 1);
for (i = 0; i < count; ++i) {
p[i] = vs[i];
}
p[count] = p[0];
let minArea: number = Number.MAX_VALUE;
for (i = 1; i <= count; ++i) {
const root: b2Vec2 = p[i - 1];
//b2Vec2 ux = p[i] - root;
let uxX: number = p[i].x - root.x;
let uxY: number = p[i].y - root.y;
//var length:number = ux.Normalize();
const length: number = Math.sqrt(uxX * uxX + uxY * uxY);
uxX /= length;
uxY /= length;
//b2Settings.b2Assert(length > Number.MIN_VALUE);
//b2Vec2 uy(-ux.y, ux.x);
const uyX: number = -uxY;
const uyY: number = uxX;
//b2Vec2 lower(FLT_MAX, FLT_MAX);
let lowerX: number = Number.MAX_VALUE;
let lowerY: number = Number.MAX_VALUE;
//b2Vec2 upper(-FLT_MAX, -FLT_MAX);
let upperX: number = -Number.MAX_VALUE;
let upperY: number = -Number.MAX_VALUE;
for (let j: number /** int */ = 0; j < count; ++j) {
//b2Vec2 d = p[j] - root;
const dX: number = p[j].x - root.x;
const dY: number = p[j].y - root.y;
//b2Vec2 r;
//var rX:number = b2Dot(ux, d);
const rX: number = (uxX * dX + uxY * dY);
//var rY:number = b2Dot(uy, d);
const rY: number = (uyX * dX + uyY * dY);
//lower = b2Min(lower, r);
if (rX < lowerX) lowerX = rX;
if (rY < lowerY) lowerY = rY;
//upper = b2Max(upper, r);
if (rX > upperX) upperX = rX;
if (rY > upperY) upperY = rY;
}
const area: number = (upperX - lowerX) * (upperY - lowerY);
if (area < 0.95 * minArea) {
minArea = area;
//obb->R.col1 = ux;
obb.R.col1.x = uxX;
obb.R.col1.y = uxY;
//obb->R.col2 = uy;
obb.R.col2.x = uyX;
obb.R.col2.y = uyY;
//b2Vec2 center = 0.5f * (lower + upper);
const centerX: number = 0.5 * (lowerX + upperX);
const centerY: number = 0.5 * (lowerY + upperY);
//obb->center = root + b2Mul(obb->R, center);
const tMat: b2Mat22 = obb.R;
obb.center.x = root.x + (tMat.col1.x * centerX + tMat.col2.x * centerY);
obb.center.y = root.y + (tMat.col1.y * centerX + tMat.col2.y * centerY);
//obb->extents = 0.5f * (upper - lower);
obb.extents.x = 0.5 * (upperX - lowerX);
obb.extents.y = 0.5 * (upperY - lowerY);
}
}
//b2Settings.b2Assert(minArea < Number.MAX_VALUE);
}
}