add client side terrain without collision

.gitignore

@@ -128,3 +128,5 @@ dist
 .yarn/build-state.yml
 .yarn/install-state.gz
 .pnp.*
+
+public/temp

src/entity.js

@@ -1,4 +1,4 @@
-import * as THREE from 'three'
+import { Vector2 } from 'three'
 import SAT from 'sat'
 import SATX from './satx.js'
 
@@ -7,7 +7,7 @@ export default class Entity {
   speed = 400
   radius = 0
 
-  #position = new THREE.Vector2(0, 0)
+  #position = new Vector2()
   #dest = null
   #game = null
 
@@ -40,7 +40,7 @@ export default class Entity {
   }
 
   moveAction(x, y) {
-    this.#dest = new THREE.Vector3(x, y, 0)
+    this.#dest = new Vector2(x, y)
   }
 
   state() {
@@ -60,7 +60,7 @@ export default class Entity {
   takeStep() {
     const speed = this.speed / (this.game?.tickBudget ?? 1000)
     if (this.#dest != null) {
-      const fixedDest = new THREE.Vector2(
+      const fixedDest = new Vector2(
         Math.min(Math.max(this.radius, this.#dest.x), (this.game?.width ?? Infinity) - this.radius),
         Math.min(Math.max(this.radius, this.#dest.y), (this.game?.height ?? Infinity) - this.radius),
       )

src/game.js

@@ -8,10 +8,12 @@ export default class Game {
 
   #entities = []
   #eventEmitter = new EventEmitter()
+  #terrains = []
   #tickBudget = Math.floor(1000 / this.tickRate)
 
   get entities() { return this.#entities }
   get eventEmitter() { return this.#eventEmitter }
+  get terrains() { return this.#terrains }
   get tickBudget() { return this.#tickBudget }
 
   spawn_entity(entity) {
@@ -19,10 +21,15 @@ export default class Game {
     entity.game = this
   }
 
+  add_terrain(terrain) {
+    this.#terrains.push(terrain)
+  }
+
   state() {
     return {
       ...this,
       entities: this.#entities.map((e) => e.state()),
+      terrains: this.#terrains.map((t) => t.state()),
     }
   }
 

src/index.js

@@ -2,6 +2,7 @@ import express from 'express'
 import { WebSocketExpress } from 'websocket-express'
 import Game from './game.js'
 import Entity from './entity.js'
+import Terrain from './terrain.js'
 
 const app = new WebSocketExpress()
 const port = 1280
@@ -39,11 +40,11 @@ app.ws('/ws', async (req, res) => {
 app.listen(port, () => {
   console.log(`Server started! Visit http://localhost:${port}`)
 
-  const entity = new Entity()
-  entity.id = '1'
-  entity.teleport(100, 100)
-  entity.radius = 35
-  game.spawn_entity(entity)
+  const entity1 = new Entity()
+  entity1.id = '1'
+  entity1.teleport(100, 100)
+  entity1.radius = 35
+  game.spawn_entity(entity1)
 
   const entity2 = new Entity()
   entity2.id = '2'
@@ -51,5 +52,20 @@ app.listen(port, () => {
   entity2.radius = 35
   game.spawn_entity(entity2)
 
+  const vertices = [
+    { x: 0, y: 0 },
+    { x: 20, y: 0 },
+    { x: 20, y: 20 },
+    { x: 10, y: 20 },
+    { x: 10, y: 5 },
+    { x: 5, y: 5 },
+    { x: 5, y: 20 },
+    { x: 0, y: 20 },
+  ]
+
+  const terrain1 = new Terrain(vertices)
+  terrain1.id = 'a'
+  game.add_terrain(terrain1)
+
   game.start()
 })

src/satx.js

@@ -6,6 +6,18 @@ export default class SATX {
       return SAT.testCircleCircle(collider1, collider2)
     }
 
+    if (collider1 instanceof SAT.Circle && collider2 instanceof SAT.Polygon) {
+      return SAT.testCirclePolygon(collider1, collider2)
+    }
+
+    if (collider1 instanceof SAT.Polygon && collider2 instanceof SAT.Circle) {
+      return SAT.testPolygonCircle(collider1, collider2)
+    }
+
+    if (collider1 instanceof SAT.Polygon && collider2 instanceof SAT.Polygon) {
+      return SAT.testPolygonPolygon(collider1, collider2)
+    }
+
     return false
   }
 }

src/terrain.js

@@ -0,0 +1,61 @@
+import SAT from 'sat'
+import { Shape, ShapeUtils, Vector2 } from 'three'
+
+export default class Terrain {
+  id = crypto.randomUUID()
+
+  position = new Vector2()
+  relativeVertices = []
+
+  #colliders = []
+  #vertices = []
+
+  constructor(vertices) {
+    this.#vertices = vertices.map((v) => new Vector2(v.x, v.y))
+    this.#calculateColliders()
+    this.#calculatePosition()
+    this.#calculateRelativeVertices()
+  }
+
+  get colliders() { return this.#colliders }
+  get vertices() { return this.#vertices }
+
+  state() {
+    return {
+      ...this,
+      position: {
+        x: this.x,
+        y: this.y,
+      },
+    }
+  }
+
+  #calculateColliders() {
+    const complexShape = new Shape()
+
+    complexShape.moveTo(this.#vertices.at(0).x, this.#vertices.at(0).y)
+    this.#vertices.slice(1).forEach((v) => complexShape.lineTo(v.x, v.y))
+
+    const points = complexShape.extractPoints(16)
+
+    const indicesToPolygon = (indices) => {
+      const satPoints = [
+        new SAT.Vector(...points.shape[indices[0]].toArray()),
+        new SAT.Vector(...points.shape[indices[1]].toArray()),
+        new SAT.Vector(...points.shape[indices[2]].toArray()),
+      ]
+
+      return new SAT.Polygon(satPoints[0], [new SAT.Vector(), satPoints[1], satPoints[2]])
+    }
+
+    this.#colliders = ShapeUtils.triangulateShape(points.shape, points.holes).map(indicesToPolygon)
+  }
+
+  #calculatePosition() {
+    this.position = this.#vertices.reduce(((sum, v) => sum.add(v)), new Vector2()).divideScalar(this.#vertices.length)
+  }
+
+  #calculateRelativeVertices() {
+    this.relativeVertices = this.#vertices.map((v) => v.clone().sub(this.position))
+  }
+}