性能优化 InstanceMesh(Point) + BufferGeometry + Label

src/components/ThreePerfView.vue

@@ -7,7 +7,8 @@
       <div class="demo-color-block">
         <span class="demonstration">物体数:<el-text type="danger">{{ restate.objects }}</el-text></span>
         <span class="demonstration"> 顶点数:<el-text type="danger">{{ restate.vertices }}</el-text></span>
-        <span class="demonstration"> 三角形数:<el-text type="danger">{{ restate.faces }}</el-text></span>
+        <span class="demonstration"> 三角形:<el-text type="danger">{{ restate.faces }}</el-text></span>
+        <span class="demonstration"> 标签:<el-text type="danger">{{ restate.viewLabelCount }}</el-text></span>
       </div>
     </el-space>
     <div class="main-content">
@@ -179,26 +180,58 @@ function test2() {
   refreshCount()
 }
 
+function isLabelInView(label, frustum, cameraPosition, maxDistance = 65) {
+  const pos = new THREE.Vector3()
+  label.getWorldPosition(pos)
+
+  // 正交相机的视锥体范围
+  if (frustum.containsPoint(pos)) {
+    // 检查标签是否在相机位置的最大距离内
+    if (shouldShowLabel(label)) {
+      return true
+    }
+  }
+  return false
+}
+
+const labels: Text[] = []
+
+function getLabelPixelSize(fontSize, cameraZoom) {
+  const pixelRatio = renderer.getPixelRatio()
+  const referenceZoom = 1
+  const referenceFontSize = 0.2
+  const referencePixelSize = 16 // fontSize=0.2, zoom=1 时显示为 16px
+
+  const scale = (fontSize / referenceFontSize) * (cameraZoom / referenceZoom)
+  return referencePixelSize * scale * pixelRatio
+}
+
+function shouldShowLabel(label, minPixelSize = 700) {
+  const pixelSize = getLabelPixelSize(label.fontSize, camera.zoom)
+  console.log(`pixel size: ${pixelSize}`)
+  return pixelSize >= minPixelSize
+}
+
 /**
- * BufferGeometry + Label
+ * InstanceMesh(Point) + BufferGeometry + Label
  */
 function test3() {
-  cleanupThree()
-  const xcount = 100
+  cleanupThree() // 清空画布
+  const xcount = 300
   const zcount = 100
   const dist = 1.25
   const spacing = dist
   const y = 0.1
 
-
   const noShaderMaterial = new THREE.MeshBasicMaterial({
     color: 0xFFFF99,
     transparent: true,
     depthWrite: false,
     side: THREE.DoubleSide
   })
-  const planeGeometry = new THREE.PlaneGeometry(0.25, 0.25) // 设置大小
+  const planeGeometry = new THREE.PlaneGeometry(0.25, 0.25)
 
+  // 使用 InstancedMesh 网格优化
   const instancedMesh = new THREE.InstancedMesh(planeGeometry, noShaderMaterial, zcount * xcount)
   instancedMesh.instanceMatrix.setUsage(THREE.DynamicDrawUsage)
   const dummy = new THREE.Object3D()
@@ -212,7 +245,7 @@ function test3() {
       const pz = z * dist
 
       dummy.position.set(px, y, pz)
-      dummy.rotation.set(-Math.PI / 2, 0, 0) // 假设你想让平面朝上，相当于面对相机视角的一部分
+      dummy.rotation.set(-Math.PI / 2, 0, 0)
       dummy.updateMatrix()
       instancedMesh.setMatrixAt(z * xcount + x, dummy.matrix)
 
@@ -222,9 +255,9 @@ function test3() {
   scene.add(instancedMesh)
 
   const positions = []
-  const labels = []
+  labels.length = 0
 
-  function createTextLabel(text, position) {
+  function createTextLabel(text, position): Text {
     const label = new Text()
     label.text = text
     label.font = SimSunTTF
@@ -243,7 +276,8 @@ function test3() {
 
     label.position.set(position.x, position.y + 0.3, position.z - 0.2)
     label.quaternion.copy(camera.quaternion)
-    label.sync()
+    label.visible = false
+    // label.sync()
 
     return label
   }
@@ -290,8 +324,9 @@ function test3() {
   lineSegments.name = 'grid-lines'
   scene.add(lineSegments)
 
-  // labels.forEach(label => scene.add(label))
+  labels.forEach(label => scene.add(label))
 
+  // 统计总数量
   refreshCount()
 }
 
@@ -299,6 +334,7 @@ function test3() {
 const restate = reactive({
   targetColor: '#ff0000',
   loadScale: 1,
+  viewLabelCount: 0,
   mode: 'translate',
   objects: 0,
   vertices: 0,
@@ -399,16 +435,52 @@ function initThree() {
   statsControls.dom.style.left = 'auto'
   viewerDom.appendChild(statsControls.dom)
 
-  renderer.setAnimationLoop(renderView)
+  renderer.setAnimationLoop(animate)
   renderer.setClearColor(0x000000, 0)
 
   // animate()
 }
 
 // 动画循环
+let frameCount = 0
+
 function animate() {
-  animationFrameId = requestAnimationFrame(animate)
+  // animationFrameId = requestAnimationFrame(animate)
   renderView()
+
+  if (frameCount++ % 60 === 0) { // 每 60 帧更新一次文本
+    const frustum = new THREE.Frustum()
+    const cameraCopy = camera.clone()
+
+    // 必须更新相机的世界矩阵
+    cameraCopy.updateMatrixWorld()
+
+    // 构造投影矩阵
+    const projScreenMatrix = new THREE.Matrix4().multiplyMatrices(
+      cameraCopy.projectionMatrix,
+      cameraCopy.matrixWorldInverse
+    )
+
+    // 设置视锥体
+    frustum.setFromProjectionMatrix(projScreenMatrix)
+
+    let viewLabelCount = 0
+    labels.forEach((label: Text) => {
+      // label.quaternion.copy(camera.quaternion) // billboard 效果保持朝向相机
+      const isvis = isLabelInView(label, frustum, camera.position)
+      if (isvis) {
+        viewLabelCount++
+      }
+      if (isvis && label.visible === false) {
+        label.visible = true
+        label.sync()
+      } else if (!isvis && label.visible === true) {
+        label.visible = false
+        label.sync()
+      }
+    })
+    restate.viewLabelCount = viewLabelCount
+  }
 }
 
 function handleResize(entries) {