116 lines
3.1 KiB
TypeScript
116 lines
3.1 KiB
TypeScript
import type { Vec3 } from "../math/Vec3"
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/** A 2.5D box: horizontal footprint plus top height. */
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export type BoxCollider = {
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shape: "box"
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minX: number
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maxX: number
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minZ: number
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maxZ: number
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top: number
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standable: boolean
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}
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/** A 2.5D circle: horizontal footprint plus top height. */
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export type CircleCollider = {
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shape: "circle"
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x: number
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z: number
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radius: number
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top: number
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standable: boolean
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}
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/** Finite engine collision capabilities, not game-content identity. */
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export type Collider = BoxCollider | CircleCollider
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export namespace Collider {
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export function centerX(collider: Collider): number {
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return collider.shape === "circle"
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? collider.x
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: (collider.minX + collider.maxX) * 0.5
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}
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export function centerZ(collider: Collider): number {
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return collider.shape === "circle"
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? collider.z
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: (collider.minZ + collider.maxZ) * 0.5
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}
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export function contains(collider: Collider, x: number, z: number): boolean {
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if (collider.shape === "circle") {
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const dx = x - collider.x
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const dz = z - collider.z
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return dx * dx + dz * dz <= collider.radius * collider.radius
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}
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return (
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x >= collider.minX &&
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x <= collider.maxX &&
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z >= collider.minZ &&
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z <= collider.maxZ
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)
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}
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/** Push a horizontal player circle out of one collider. */
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export function pushOut(
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collider: Collider,
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position: Vec3,
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radius: number,
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): void {
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if (collider.shape === "circle") {
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pushFromCircle(position, radius, collider)
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return
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}
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pushFromBox(position, radius, collider)
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}
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function pushFromBox(position: Vec3, radius: number, box: BoxCollider): void {
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const cx = Math.max(box.minX, Math.min(box.maxX, position.x))
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const cz = Math.max(box.minZ, Math.min(box.maxZ, position.z))
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const dx = position.x - cx
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const dz = position.z - cz
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const distanceSquared = dx * dx + dz * dz
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if (distanceSquared >= radius * radius) {
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return
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}
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if (distanceSquared > 1e-6) {
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const distance = Math.sqrt(distanceSquared)
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const push = (radius - distance) / distance
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position.x += dx * push
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position.z += dz * push
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return
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}
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const left = position.x - box.minX
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const right = box.maxX - position.x
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const near = position.z - box.minZ
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const far = box.maxZ - position.z
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const nearest = Math.min(left, right, near, far)
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if (nearest === left) {
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position.x = box.minX - radius
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} else if (nearest === right) {
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position.x = box.maxX + radius
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} else if (nearest === near) {
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position.z = box.minZ - radius
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} else {
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position.z = box.maxZ + radius
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}
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}
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function pushFromCircle(
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position: Vec3,
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radius: number,
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circle: CircleCollider,
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): void {
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const dx = position.x - circle.x
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const dz = position.z - circle.z
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const reach = radius + circle.radius
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const distanceSquared = dx * dx + dz * dz
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if (distanceSquared >= reach * reach || distanceSquared < 1e-6) {
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return
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}
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const distance = Math.sqrt(distanceSquared)
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const push = (reach - distance) / distance
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position.x += dx * push
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position.z += dz * push
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}
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}
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