FINALLY some working LOD terrain!

src/engine/components/index.js

@@ -157,6 +157,17 @@ class Node {
     return this.pos
   }
 
+  get absolutePosition () {
+    let p
+    if (this.parent) {
+      p = this.parent.absolutePosition
+      p = [p[0] + this.pos[0], p[1] + this.pos[1], p[2] + this.pos[2]]
+    } else {
+      p = this.pos
+    }
+    return p
+  }
+
   // Draw base
   draw (gl, shader) {
     // Nothing to draw here, so just draw children

src/engine/components/terrain/experimental.js

@@ -1,96 +0,0 @@
-import { Node } from '../'
-import { Mesh } from '../../mesh'
-import { vec3 } from 'gl-matrix'
-import { subv3, mulv3, addv3, normalv3 } from '../../utility'
-
-class Terrain extends Node {
-  constructor (pos, sWidth, sHeight, face = [0.0, -1.0, 0.0]) {
-    super(pos)
-
-    this.width = sWidth
-    this.height = sHeight
-
-    this.mesh = null
-
-    // Calculate left and forward vectors
-    this.left = [face[1], face[2], face[0]] || [1.0, 0.0, 0.0]
-    this.forward = [0.0, 0.0, -1.0]
-    vec3.cross(this.forward, face, this.left)
-  }
-
-  createMesh (gl, heightMap) {
-    // Center the mesh
-    let cpoint = [0.0, 0.0, 0.0]
-    cpoint = subv3(cpoint, mulv3(this.left, heightMap.size / 2))
-    cpoint = subv3(cpoint, mulv3(this.forward, heightMap.size / 2))
-
-    let VERTICES = heightMap.size
-    let count = VERTICES * VERTICES
-    let vertices = new Array(count * 3)
-    let normals = new Array(count * 3)
-    let textureCoords = new Array(count * 2)
-    let indices = new Array(6 * (VERTICES - 1) * (VERTICES - 1))
-    let vertexPointer = 0
-
-    for (let i = 0; i < VERTICES; i++) {
-      for (let j = 0; j < VERTICES; j++) {
-        let isize = j / (VERTICES - 1) * this.width / 2
-        let jsize = i / (VERTICES - 1) * this.height / 2
-
-        // From the left and forward vectors, we can calculate an oriented vertex
-        let iv = mulv3(this.left, isize)
-        let jv = mulv3(this.forward, jsize)
-
-        // Add the scaled left and forward to the centered origin
-        let pos = addv3(cpoint.slice(0), addv3(iv, jv))
-
-        vertices[vertexPointer * 3] = pos[0]
-        vertices[vertexPointer * 3 + 1] = pos[1]
-        vertices[vertexPointer * 3 + 2] = pos[2]
-        let normal = [0.0, 1.0, 0.0] // heightMap.getNormal(j, i)
-        normals[vertexPointer * 3] = normal[0]
-        normals[vertexPointer * 3 + 1] = normal[1]
-        normals[vertexPointer * 3 + 2] = normal[2]
-        textureCoords[vertexPointer * 2] = j / (VERTICES - 1)
-        textureCoords[vertexPointer * 2 + 1] = i / (VERTICES - 1)
-        vertexPointer++
-      }
-    }
-
-    let pointer = 0
-    for (let gz = 0; gz < VERTICES - 1; gz++) {
-      for (let gx = 0; gx < VERTICES - 1; gx++) {
-        let topLeft = (gz * VERTICES) + gx
-        let topRight = topLeft + 1
-        let bottomLeft = ((gz + 1) * VERTICES) + gx
-        let bottomRight = bottomLeft + 1
-        indices[pointer++] = topLeft
-        indices[pointer++] = bottomLeft
-        indices[pointer++] = topRight
-        indices[pointer++] = topRight
-        indices[pointer++] = bottomLeft
-        indices[pointer++] = bottomRight
-      }
-    }
-
-    this.mesh = Mesh.construct(gl, vertices, indices, textureCoords, normals)
-  }
-
-  setMaterial (mat) {
-    this.mesh.material = mat
-  }
-
-  draw (gl, shader) {
-    if (!this.mesh) return
-    // Set model transform matrix uniform
-    const transformLocation = shader.getUniformLocation(gl, 'uModelMatrix')
-    gl.uniformMatrix4fv(transformLocation, false, this.transform)
-
-    this.mesh.prepare(gl, shader)
-    this.mesh.draw(gl, shader)
-
-    super.draw(gl, shader)
-  }
-}
-
-export { Terrain }

src/engine/components/terrain/lod.js

@@ -0,0 +1,207 @@
+import { Node } from '../'
+import { BoundingBox } from '../../mesh/aabb'
+import { Mesh } from '../../mesh'
+import { vec3 } from 'gl-matrix'
+import { addv3 } from '../../utility'
+
+class TerrainNode extends Node {
+  constructor (root, pos, level) {
+    super(pos)
+
+    this.root = root
+    this.level = level
+
+    this.mesh = null
+  }
+
+  createMesh (gl) {
+    if (this.children.length) {
+      let generated = 0
+      for (let i in this.children) {
+        if (generated >= this.root.genPerTick) break
+        let child = this.children[i]
+        if (!(child instanceof TerrainNode)) continue
+        generated += this.children[i].createMesh(gl)
+      }
+      return generated
+    }
+
+    if (this.mesh) return 0
+
+    let VERTICES = this.root.resolution
+    let count = VERTICES * VERTICES
+    let vertices = new Array(count * 3)
+    let normals = new Array(count * 3)
+    let textureCoords = new Array(count * 2)
+    let indices = new Array(6 * (VERTICES - 1) * (VERTICES - 1))
+    let vertexPointer = 0
+    let divisionLevel = Math.pow(2, this.level)
+
+    for (let i = 0; i < VERTICES; i++) {
+      for (let j = 0; j < VERTICES; j++) {
+        let vertDivj = j / (VERTICES - 1)
+        let vertDivi = i / (VERTICES - 1)
+
+        let pj = vertDivj * this.root.width / divisionLevel
+        let pi = vertDivi * this.root.height / divisionLevel
+
+        vertices[vertexPointer * 3] = pj
+        vertices[vertexPointer * 3 + 1] = this.root.generator.getHeight(this.absolutePosition[0] + pj, this.absolutePosition[2] + pi)
+        vertices[vertexPointer * 3 + 2] = pi
+        let normal = this.root.generator.getNormal(this.absolutePosition[0] + pj, this.absolutePosition[2] + pi)
+        normals[vertexPointer * 3] = normal[0]
+        normals[vertexPointer * 3 + 1] = normal[1]
+        normals[vertexPointer * 3 + 2] = normal[2]
+        textureCoords[vertexPointer * 2] = j / (VERTICES - 1)
+        textureCoords[vertexPointer * 2 + 1] = i / (VERTICES - 1)
+        vertexPointer++
+      }
+    }
+
+    let pointer = 0
+    for (let gz = 0; gz < VERTICES - 1; gz++) {
+      for (let gx = 0; gx < VERTICES - 1; gx++) {
+        let topLeft = (gz * VERTICES) + gx
+        let topRight = topLeft + 1
+        let bottomLeft = ((gz + 1) * VERTICES) + gx
+        let bottomRight = bottomLeft + 1
+        indices[pointer++] = topLeft
+        indices[pointer++] = bottomLeft
+        indices[pointer++] = topRight
+        indices[pointer++] = topRight
+        indices[pointer++] = bottomLeft
+        indices[pointer++] = bottomRight
+      }
+    }
+
+    this.mesh = Mesh.construct(gl, vertices, indices, textureCoords, normals)
+    this.mesh.material = this.root.material
+    this.bounds = BoundingBox.fromMesh(this.mesh)
+
+    if (this.parent && this.parent.mesh) {
+      this.parent.dispose()
+    }
+
+    return 1
+  }
+
+  draw (gl, shader) {
+    super.draw(gl, shader)
+    if (!this.mesh) return
+    // Set model transform matrix uniform
+    const transformLocation = shader.getUniformLocation(gl, 'uModelMatrix')
+    gl.uniformMatrix4fv(transformLocation, false, this.transform)
+
+    this.mesh.prepare(gl, shader)
+    this.mesh.draw(gl, shader)
+  }
+
+  get generated () {
+    return this.mesh != null
+  }
+
+  dispose () {
+    this.mesh = null
+  }
+
+  merge () {
+    if (this.children.length === 0) return
+    for (let i in this.children) {
+      this.children[i].merge()
+      this.children[i].dispose()
+    }
+
+    this.children = []
+  }
+
+  subdivide () {
+    if (this.level === this.root.maxDetail) return
+    let lv = this.level + 1
+
+    let stepLeft = this.root.width / Math.pow(2, lv)
+    let stepForward = this.root.height / Math.pow(2, lv)
+
+    this.addChild(new TerrainNode(this.root, [0, 0, 0], lv))
+    this.addChild(new TerrainNode(this.root, [stepLeft, 0, 0], lv))
+    this.addChild(new TerrainNode(this.root, [0, 0, stepForward], lv))
+    this.addChild(new TerrainNode(this.root, [stepLeft, 0, stepForward], lv))
+  }
+
+  update (camera) {
+    if (!this.bounds) return false
+    let distCamera = vec3.distance(camera.pos, addv3(this.bounds.center, this.absolutePosition))
+    let lodDistance = this.root.lodDistance - (Math.pow(2, this.level) * 16)
+    if (this.children.length) {
+      if (distCamera > lodDistance + 16 && this.level >= 1) {
+        this.merge()
+        return true
+      }
+
+      let acted = false
+      for (let i in this.children) {
+        let child = this.children[i]
+        acted = child.update(camera)
+      }
+      return acted
+    }
+
+    if (distCamera < lodDistance && this.level < this.root.maxDetail) {
+      this.subdivide()
+
+      return true
+    }
+
+    return false
+  }
+}
+
+class LODTerrain extends Node {
+  constructor (pos, sWidth, sHeight, lodDistance = 1024, maxDetail = 4, resolution = 32, genPerTick = 4) {
+    super(pos)
+
+    this.width = sWidth
+    this.height = sHeight
+
+    this.genPerTick = genPerTick
+    this.lodDistance = lodDistance
+    this.maxDetail = maxDetail
+    this.resolution = resolution
+
+    this.addChild(new TerrainNode(this, pos, 1))
+    this.addChild(new TerrainNode(this, [pos[0] + sWidth / 2, pos[1], pos[2]], 1))
+    this.addChild(new TerrainNode(this, [pos[0], pos[1], pos[2] + sHeight / 2], 1))
+    this.addChild(new TerrainNode(this, [pos[0] + sWidth / 2, pos[1], pos[2] + sHeight / 2], 1))
+  }
+
+  setGenerator (generator) {
+    this.generator = generator
+  }
+
+  setMaterial (mat) {
+    this.material = mat
+  }
+
+  createMesh (gl) {
+    // Ensure only one mesh is generated every tick
+    let generated = 0
+    for (let i in this.children) {
+      if (generated >= this.genPerTick) break
+      let child = this.children[i]
+      if (!(child instanceof TerrainNode)) continue
+      generated += this.children[i].createMesh(gl)
+    }
+    return generated
+  }
+
+  update (camera) {
+    let acted = false
+    for (let i in this.children) {
+      if (acted) break
+      let child = this.children[i]
+      acted = child.update(camera)
+    }
+    return acted
+  }
+}
+
+export { LODTerrain }

src/index.js

@@ -3,7 +3,7 @@ import Camera from './engine/camera'
 import loadMesh from './engine/mesh/loader'
 
 import { Environment } from './engine/environment'
-import { Terrain } from './engine/components/terrain'
+import { LODTerrain } from './engine/components/terrain/lod'
 import { SimplexHeightMap } from './engine/components/terrain/heightmap'
 import { Material } from './engine/mesh/material'
 
@@ -22,13 +22,14 @@ async function pipeline () {
   let hmap = new SimplexHeightMap(1, 1, 256, 50)
 
   // Create a terrain
-  let terrain = new Terrain([0.0, 0.0, 0.0], 256, 256)
+  let terrain = new LODTerrain([0.0, 0.0, 0.0], 1024, 1024, 850, 4)
-  terrain.createMesh(game.gl, hmap)
 
   // Terrain material
   let material = new Material()
   material.textures = ['grass-1024.jpg']
   await material.loadTextures(game.gl)
+
+  terrain.setGenerator(hmap)
   terrain.setMaterial(material)
 
   // Create and initialize the camera
@@ -36,7 +37,6 @@ async function pipeline () {
   cam.updateProjection(game.gl)
 
   // Update function for camera
-  let face = 0
   game.addUpdateFunction(function (dt) {
     if (game.input.isDown('w')) {
       cam.processKeyboard(0, dt)
@@ -54,10 +54,13 @@ async function pipeline () {
       cam.processMouseMove(game.input.mouseOffset)
     }
 
+    // Update LOD meshes
+    terrain.update(cam)
+    terrain.createMesh(game.gl)
+
     // TESTING: Move model forward
     // t = t + 0.1
     // entity.setPosition([t, 0.0, 0.0])
-    if (face > 5) face = 0
   })
 
   // Render function for the triangle