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instructions-clear/src/satx.js
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2025-01-11 18:17:44 +09:00

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JavaScript

import SAT from 'sat'
import { Vector2 } from 'three'
import Entity from './entity.js'
export default class SATX {
static clamp(vectorOrObject, maxX = Infinity, maxY = Infinity, radius = 0) {
let modified = null
if (vectorOrObject instanceof Vector2) {
modified = vectorOrObject.clone()
}
else if (vectorOrObject instanceof SAT.Vector) {
modified = new SAT.Vector(vectorOrObject.x, vectorOrObject.y)
}
else {
modified = { x: vectorOrObject.x, y: vectorOrObject.y }
}
modified.x = Math.min(Math.max(radius, vectorOrObject.x), (maxX ?? Infinity) - radius)
modified.y = Math.min(Math.max(radius, vectorOrObject.y), (maxY ?? Infinity) - radius)
return modified
}
static collideObject(collider1, collider2, result = null) {
if (collider1 instanceof SAT.Circle && collider2 instanceof SAT.Circle) {
return SAT.testCircleCircle(collider1, collider2, result)
}
if (collider1 instanceof SAT.Circle && collider2 instanceof SAT.Polygon) {
return SAT.testCirclePolygon(collider1, collider2, result)
}
if (collider1 instanceof SAT.Polygon && collider2 instanceof SAT.Circle) {
return SAT.testPolygonCircle(collider1, collider2, result)
}
if (collider1 instanceof SAT.Polygon && collider2 instanceof SAT.Polygon) {
return SAT.testPolygonPolygon(collider1, collider2, result)
}
return false
}
static collideObjects(collider1, colliders) {
return colliders.some((c) => this.collideObject(collider1, c))
}
static enclosingRegularPolygonRadius(numberOfVertices) {
return 1 / Math.cos(Math.PI / numberOfVertices)
}
static entityTunnel(fromX, fromY, toX, toY, radius = 0) {
if (radius <= 0) {
return this.line(fromX, fromY, toX, toY)
}
const sides = new Float32Array(5)
sides[0] = toX - fromX
sides[1] = toY - fromY
sides[4] = Math.hypot(sides[0], sides[1])
sides[2] = (sides[1] / sides[4]) * -radius // optimization: negation and swapping rotates
sides[3] = (sides[0] / sides[4]) * radius
return new SAT.Polygon(new SAT.Vector(fromX - sides[2], fromY - sides[3]), [
new SAT.Vector(),
new SAT.Vector(sides[0], sides[1]),
new SAT.Vector(sides[0] + (2 * sides[2]), sides[1] + (2 * sides[3])),
new SAT.Vector(2 * sides[2], 2 * sides[3]),
])
}
static fixCollisions(entityPosition, colliders, radius = 0, maxX = Infinity, maxY = Infinity) {
if (!this.collideObjects(Entity.collider(entityPosition.x, entityPosition.y, radius), colliders)) {
return entityPosition
}
// console.time('fixCollisions')
let direction = new Vector2(0, 5)
let multiplier = 1
const rotationSlices = 16
for (let limit = 1; limit <= 10000; limit++) {
const rads = (limit % rotationSlices) * 2 * Math.PI / rotationSlices
const offset = direction.clone().rotateAround(new Vector2(), rads).multiplyScalar(multiplier)
const position = SATX.clamp(entityPosition.clone().add(offset), maxX, maxY, radius)
if (!this.collideObjects(Entity.collider(position.x, position.y, radius), colliders)) {
// console.timeEnd('fixCollisions')
return position
}
if (limit % rotationSlices == 0) {
multiplier++
}
}
// console.timeEnd('fixCollisions')
console.error('ERROR: can\'t fix collision')
}
static line(fromX, fromY, toX, toY) {
return new SAT.Polygon(new SAT.Vector(fromX, fromY), [new SAT.Vector(), new SAT.Vector(toX - fromX, toY - fromY)])
}
static satPolygonToVectors(polygon) {
const position = new Vector2(polygon.pos.x, polygon.pos.y)
return polygon.points.map((p) => new Vector2(p.x, p.y).add(position))
}
static vectorToFloat32Array(vector) {
const array = new Float32Array(2)
array[0] = vector.x
array[1] = vector.y
return array
}
static float32ArrayToVector(array) {
return new Vector2(array[0], array[1])
}
static float32ArrayWithIndexToVector(array, index) {
return new Vector2(array[index], array[index + 1])
}
}