42a7db75ec
adamk@ says these are pretty stable. R=abarth@chromium.org Review URL: https://codereview.chromium.org/845403009
63 lines
1.8 KiB
Plaintext
63 lines
1.8 KiB
Plaintext
<!--
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// Copyright 2015 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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-->
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<import src="/sky/framework/sky-element/sky-element.sky" as="SkyElement" />
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<sky-element name="fps-counter" attributes="showHistory:boolean">
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<template>
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<template if="{{ showHistory }}">
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<template repeat="{{ history }}">
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<div>{{ }} ms</div>
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</template>
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<div>max = {{ max }} ms</div>
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</template>
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<div>fps = {{ framerate }} Hz</div>
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</template>
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<script>
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var kMaxDeltaLength = 10;
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module.exports = class extends SkyElement {
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created() {
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this.framerate = "...";
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this.max = 0;
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this.lastTimeStamp = 0;
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this.rafId = 0;
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this.currentDeltaIndex = 0;
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this.deltas = new Array(kMaxDeltaLength);
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this.deltas.fill(0);
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this.history = new Array(kMaxDeltaLength);
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this.history.fill(0);
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}
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attached() {
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this.scheduleTick();
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}
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detached() {
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cancelAnimationFrame(this.rafId);
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this.rafId = 0;
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}
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scheduleTick() {
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this.rafId = requestAnimationFrame(this.tick.bind(this));
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}
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tick(timeStamp) {
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this.scheduleTick();
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var lastTimeStamp = this.lastTimeStamp;
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this.lastTimeStamp = timeStamp;
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if (!lastTimeStamp)
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return;
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var delta = timeStamp - lastTimeStamp;
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this.deltas[this.currentDeltaIndex++ % kMaxDeltaLength] = delta;
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for (var i = 0; i < kMaxDeltaLength; ++i) {
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var value = this.deltas[(i + this.currentDeltaIndex) % kMaxDeltaLength];
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this.history[i] = value.toFixed(2);
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}
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var sum = this.deltas.reduce(function(a, b) { return a + b }, 0);
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var avg = sum / kMaxDeltaLength;
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this.framerate = (1000 / avg).toFixed(2);
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this.max = Math.max(delta, this.max).toFixed(2);
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}
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}.register();
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</script>
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</sky-element>
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