Question

作为一名webGL开发人员，这些图表让我心碎。不可能如果垃圾收集器在主线程中运行阻止动画的工作流程超过半秒，则平滑动画可以不间断地播放

我已经尝试了所有这些，缓存，对象池，声明全局变量并使我的返回函数像状态机一样工作，直到我终于发现即使empty call to RequestAnimationFrame itself每秒也会产生高达1mb的垃圾

对RAF的Ping-pong呼叫不会改变我的系统上的垃圾创建率

假设在GC启动时没有可能拥有一个完全响应的webgl页面，我想知道是否有任何替代我们通常在webgl项目中看到的通常代码结构。起初我想使用webWorker并将主线程释放到GC而不中断动画渲染，但代价是钻研OffscreenCanvas界面，但看起来it's only supported in Firefox atm

使用setTimeout仍然会产生抖动，并且被认为是不好的做法，所以我想知道是否真的有一种解决方法可以避免GC中断

Answer 1

看起来你的测试页面正在做一些它不应该做的事情。

解析HTML

为什么每帧都在解析HTML？只有在someElement.innerHTML = "..."发生HTML更改时才会发生这种情况。

如果你要更新一个值，比如说FPS，试试这个

<div class="fps">FPS:<span id="fps"></span></div>

然后将div设为固定宽度，以便它不会根据fps改变大小

.fps { width: 100px }

然后为fps值

创建一个文本节点

var fpsNode = document.createTextNode("");
var fpsSpan = document.getElementById("fps");
fpsSpan.appendChild(fpsNode);

现在你可以像这样更新fps了

fpsSpan.nodeValue = someFPSNumber;

我的伏都教。我实际上并没有对它进行分析，但理论上这样做就意味着不需要进行HTML解析，因为每帧都没有新的HTML。最重要的是因为宽度是固定的，所以没有布局要做。

此外，你应该考虑在它自己的堆叠环境中加入类似的东西

.fps { position: absolute; z-index: 2 }

这样浏览器就可以将该元素放入其自己的纹理中，因此不必在同一堆叠上下文中使用其他元素重新渲染。

检查空白的rAF

＆＃13;

function nothing() {
  requestAnimationFrame(nothing);
}
nothing();

＆＃13;

我每1.5秒看一次1ms次要GC。你每帧有16毫秒，所以拿1来换GC不会毁了你的一天。

让我们在上面添加我的建议和一些WebGL

＆＃13;

"use strict";
var countNode = document.createTextNode("");
var countElem = document.getElementById("count");
countElem.appendChild(countNode);

twgl.setDefaults({attribPrefix: "a_"});
var m4 = twgl.m4;
var gl = twgl.getWebGLContext(document.getElementById("c"));
var programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);

var bufferInfo = twgl.primitives.createCubeBufferInfo(gl, 2);

var tex = twgl.createTexture(gl, {
  min: gl.NEAREST,
  mag: gl.NEAREST,
  src: [
    255, 255, 255, 255,
    192, 192, 192, 255,
    192, 192, 192, 255,
    255, 255, 255, 255,
  ],
});

var camera = m4.identity();
var view = m4.identity();
var projection = m4.identity();
var viewProjection = m4.identity();
var world = m4.identity();
var worldInverseTranspose = m4.identity();
var worldViewProjection = m4.identity();
    
var uniforms = {
  u_lightWorldPos: new Float32Array([1, 8, -10]),
  u_lightColor: new Float32Array([1, 0.8, 0.8, 1]),
  u_ambient: new Float32Array([0, 0, 0, 1]),
  u_specular: new Float32Array([1, 1, 1, 1]),
  u_shininess: 50,
  u_specularFactor: 1,
  u_diffuse: tex,
  u_viewInverse: camera,
  u_world: world,
  u_worldInverseTranspose: worldInverseTranspose,
  u_worldViewProjection: worldViewProjection,
  
};
                             
var eye = [1, 4, -6];
var target = [0, 0, 0];
var up = [0, 1, 0];
var count = 0;                            

function render(time) {
  ++count;
  countNode.nodeValue = count;

  time *= 0.001;
  twgl.resizeCanvasToDisplaySize(gl.canvas);
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

  gl.enable(gl.DEPTH_TEST);
  gl.enable(gl.CULL_FACE);
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

  m4.perspective(30 * Math.PI / 180, gl.canvas.clientWidth / gl.canvas.clientHeight, 0.5, 10, projection);

  m4.lookAt(eye, target, up, camera);
  m4.inverse(camera, view);
  m4.multiply(view, projection, viewProjection);
  m4.rotationY(time, world);

  m4.inverse(world, worldInverseTranspose);
  m4.transpose(worldInverseTranspose, worldInverseTranspose);
  
  m4.multiply(world, viewProjection, worldViewProjection);

  gl.useProgram(programInfo.program);
  twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
  twgl.setUniforms(programInfo, uniforms);
  gl.drawElements(gl.TRIANGLES, bufferInfo.numElements, gl.UNSIGNED_SHORT, 0);

  requestAnimationFrame(render);
}
requestAnimationFrame(render);

＆＃13;

html, body, canvas {
  margin: 0;
  width: 100%;
  height: 100%;
}
.count {
  width: 100px;
  position: absolute;
  left: 1em;
  top: 1em;
  background-color: rgba(0,0,0,0.8);
  z-index: 2;
  padding: 1em;
  color: white;
}

＆＃13;

<script src="https://twgljs.org/dist/twgl-full.min.js"></script>
   <script id="vs" type="notjs">
uniform mat4 u_worldViewProjection;
uniform vec3 u_lightWorldPos;
uniform mat4 u_world;
uniform mat4 u_viewInverse;
uniform mat4 u_worldInverseTranspose;

attribute vec4 a_position;
attribute vec3 a_normal;
attribute vec2 a_texcoord;

varying vec4 v_position;
varying vec2 v_texCoord;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

void main() {
  v_texCoord = a_texcoord;
  v_position = (u_worldViewProjection * a_position);
  v_normal = (u_worldInverseTranspose * vec4(a_normal, 0)).xyz;
  v_surfaceToLight = u_lightWorldPos - (u_world * a_position).xyz;
  v_surfaceToView = (u_viewInverse[3] - (u_world * a_position)).xyz;
  gl_Position = v_position;
}
  </script>
  <script id="fs" type="notjs">
precision mediump float;

varying vec4 v_position;
varying vec2 v_texCoord;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

uniform vec4 u_lightColor;
uniform vec4 u_ambient;
uniform sampler2D u_diffuse;
uniform vec4 u_specular;
uniform float u_shininess;
uniform float u_specularFactor;

vec4 lit(float l ,float h, float m) {
  return vec4(1.0,
              max(l, 0.0),
              (l > 0.0) ? pow(max(0.0, h), m) : 0.0,
              1.0);
}

void main() {
  vec4 diffuseColor = texture2D(u_diffuse, v_texCoord);
  vec3 a_normal = normalize(v_normal);
  vec3 surfaceToLight = normalize(v_surfaceToLight);
  vec3 surfaceToView = normalize(v_surfaceToView);
  vec3 halfVector = normalize(surfaceToLight + surfaceToView);
  vec4 litR = lit(dot(a_normal, surfaceToLight),
                    dot(a_normal, halfVector), u_shininess);
  vec4 outColor = vec4((
  u_lightColor * (diffuseColor * litR.y + diffuseColor * u_ambient +
                u_specular * litR.z * u_specularFactor)).rgb,
      diffuseColor.a);
  gl_FragColor = outColor;
}
</script>
<canvas id="c"></canvas>
<div class="count">
  count: <span id="count"></span>
</div>

＆＃13;

仍然没有发现任何事情导致我的帧率下降

垃圾收集器破坏WebGL页面性能

1 个答案: