pocket-physics
Version:
Verlet physics extracted from pocket-ces demos
185 lines (184 loc) • 7.43 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.collideCircleEdge = void 0;
const v2_1 = require("./v2");
const collide_circle_circle_1 = require("./collide-circle-circle");
// Preallocations
const edgeDir = (0, v2_1.v2)();
const edge = (0, v2_1.v2)();
const prevEdge = (0, v2_1.v2)();
const hypo = (0, v2_1.v2)();
const epDiff = (0, v2_1.v2)();
const correction = (0, v2_1.v2)();
const collisionPoint = (0, v2_1.v2)();
const tunnelPoint = (0, v2_1.v2)();
const ep = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
const epBefore = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
function collideCircleEdge(circle, radius3, mass3, endpoint1, mass1, endpoint2, mass2, preserveInertia, damping) {
// Edge direction (edge in local space)
(0, v2_1.sub)(edge, endpoint2.cpos, endpoint1.cpos);
// Normalize collision edge (assume collision axis is edge)
(0, v2_1.normalize)(edgeDir, edge);
// Vector from endpoint1 to particle
(0, v2_1.sub)(hypo, circle.cpos, endpoint1.cpos);
// Where is the particle on the edge, before, after, or on?
// Also used for interpolation later.
const projection = (0, v2_1.dot)(edge, hypo);
const maxDot = (0, v2_1.dot)(edge, edge);
const edgeMag = Math.sqrt(maxDot);
// Colliding beyond the edge...
if (projection < 0 || projection > maxDot)
return;
// Create interpolation factor of where point closest
// to particle is on the line.
const t = projection / maxDot;
const u = 1 - t;
// Find the point of collision on the edge.
(0, v2_1.scale)(collisionPoint, edgeDir, t * edgeMag);
(0, v2_1.add)(collisionPoint, collisionPoint, endpoint1.cpos);
const dist = (0, v2_1.distance)(collisionPoint, circle.cpos);
// Bail if point and edge are too far apart.
if (dist > radius3)
return;
// Distribute mass of colliding point into two fake points
// and use those to collide against each endpoint independently.
const standinMass1 = u * mass3;
const standinMass2 = t * mass3;
const standin1 = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
const standin2 = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
// Slide standin1 along edge to be in front of endpoint1
(0, v2_1.scale)(standin1.cpos, edgeDir, t * edgeMag);
(0, v2_1.sub)(standin1.cpos, circle.cpos, standin1.cpos);
(0, v2_1.scale)(standin1.ppos, edgeDir, t * edgeMag);
(0, v2_1.sub)(standin1.ppos, circle.ppos, standin1.ppos);
// Slide standin2 along edge to be in front of endpoint2
(0, v2_1.scale)(standin2.cpos, edgeDir, u * edgeMag);
(0, v2_1.add)(standin2.cpos, circle.cpos, standin2.cpos);
(0, v2_1.scale)(standin2.ppos, edgeDir, u * edgeMag);
(0, v2_1.add)(standin2.ppos, circle.ppos, standin2.ppos);
const standin1Before = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
const standin2Before = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
// Stash state of standins
(0, v2_1.copy)(standin1Before.cpos, standin1.cpos);
(0, v2_1.copy)(standin1Before.ppos, standin1.ppos);
(0, v2_1.copy)(standin2Before.cpos, standin2.cpos);
(0, v2_1.copy)(standin2Before.ppos, standin2.ppos);
const edgeRadius = 0;
// Collide standins with endpoints
(0, collide_circle_circle_1.collideCircleCircle)(standin1, radius3, standinMass1, endpoint1, edgeRadius, mass1, preserveInertia, damping);
(0, collide_circle_circle_1.collideCircleCircle)(standin2, radius3, standinMass2, endpoint2, edgeRadius, mass2, preserveInertia, damping);
const standin1Delta = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
const standin2Delta = {
cpos: (0, v2_1.v2)(),
ppos: (0, v2_1.v2)()
};
// Compute standin1 cpos change
(0, v2_1.sub)(standin1Delta.cpos, standin1.cpos, standin1Before.cpos);
// Compute standin2 cpos change
(0, v2_1.sub)(standin2Delta.cpos, standin2.cpos, standin2Before.cpos);
(0, v2_1.scale)(standin1Delta.cpos, standin1Delta.cpos, u);
(0, v2_1.scale)(standin2Delta.cpos, standin2Delta.cpos, t);
// Apply cpos changes to point3
(0, v2_1.add)(circle.cpos, circle.cpos, standin1Delta.cpos);
(0, v2_1.add)(circle.cpos, circle.cpos, standin2Delta.cpos);
if (!preserveInertia)
return;
// TODO: instead of adding diff, get magnitude of diff and scale
// in reverse direction of standin velocity from point3.cpos because
// that is what circlecircle does.
// Compute standin1 ppos change
(0, v2_1.sub)(standin1Delta.ppos, standin1.ppos, standin1Before.ppos);
// Compute standin2 ppos change
(0, v2_1.sub)(standin2Delta.ppos, standin2.ppos, standin2Before.ppos);
(0, v2_1.scale)(standin1Delta.ppos, standin1Delta.ppos, u);
(0, v2_1.scale)(standin2Delta.ppos, standin2Delta.ppos, t);
// Apply ppos changes to point3
(0, v2_1.add)(circle.ppos, circle.ppos, standin1Delta.ppos);
(0, v2_1.add)(circle.ppos, circle.ppos, standin2Delta.ppos);
}
exports.collideCircleEdge = collideCircleEdge;
function snapshotDebug(name, particles = [], points = []) {
const cvs = document.createElement("canvas");
const ctx = cvs.getContext("2d");
document.body.appendChild(cvs);
// let minX = Number.MAX_SAFE_INTEGER;
// let maxX = Number.MIN_SAFE_INTEGER;
// let minY = Number.MAX_SAFE_INTEGER;
// let maxY = Number.MIN_SAFE_INTEGER;
// for (let i = 0; i < particles.length; i++) {
// const particle = particles[i];
// minX = Math.min(
// minX,
// particle.cpos.x - particle.radius,
// particle.ppos.x - particle.radius
// );
// maxX = Math.max(
// maxX,
// particle.cpos.x + particle.radius,
// particle.ppos.x + particle.radius
// );
// minY = Math.min(
// minY,
// particle.cpos.y - particle.radius,
// particle.ppos.y - particle.radius
// );
// maxY = Math.max(
// maxY,
// particle.cpos.y + particle.radius,
// particle.ppos.y + particle.radius
// );
// }
// for (let i = 0; i < points.length; i++) {
// const [, point] = points[i];
// minX = Math.min(minX, point.x, point.x);
// maxX = Math.max(maxX, point.x, point.x);
// minY = Math.min(minY, point.y, point.y);
// maxY = Math.max(maxY, point.y, point.y);
// }
// cvs.width = maxX - minX;
// cvs.height = maxY - minY;
// ctx.translate(-minX, -minY);
cvs.width = 800;
cvs.height = 800;
for (let i = 0; i < particles.length; i++) {
const particle = particles[i];
ctx.fillStyle = "rgba(255, 0, 0, 0.5)";
ctx.beginPath();
ctx.arc(particle.ppos.x, particle.ppos.y, particle.radius, 0, Math.PI * 2, false);
ctx.fill();
ctx.fillStyle = "rgba(0, 0, 0, 0.5)";
ctx.beginPath();
ctx.arc(particle.cpos.x, particle.cpos.y, particle.radius, 0, Math.PI * 2, false);
ctx.fill();
}
for (let i = 0; i < points.length; i++) {
const [name, point] = points[i];
ctx.fillStyle = "purple";
ctx.fillRect(point.x, point.y, 1, 1);
ctx.fillText(`${name} (${point.x},${point.y})`, point.x + 1, point.y + 1);
}
// ctx.translate(minX, minY);
ctx.fillStyle = "black";
ctx.fillText(name, 10, 10);
}