mirror of
https://github.com/scratchfoundation/scratch-vm.git
synced 2024-12-24 06:52:40 -05:00
First draft of video IO device
This commit is contained in:
Corey Frang
Michael "Z" Goddard
parent
cd7e03f0f6
commit
eef88f6c2d
3 changed files with 354 additions and 157 deletions
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@ -15,6 +15,7 @@ const DeviceManager = require('../io/deviceManager');
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const Keyboard = require('../io/keyboard');
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const Mouse = require('../io/mouse');
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const MouseWheel = require('../io/mouseWheel');
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const Video = require('../io/video');
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const defaultBlockPackages = {
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scratch3_control: require('../blocks/scratch3_control'),
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@ -260,7 +261,8 @@ class Runtime extends EventEmitter {
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deviceManager: new DeviceManager(),
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keyboard: new Keyboard(this),
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mouse: new Mouse(this),
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mouseWheel: new MouseWheel(this)
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mouseWheel: new MouseWheel(this),
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video: new Video(this)
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};
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/**
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@ -3,7 +3,7 @@ const Runtime = require('../../engine/runtime');
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const ArgumentType = require('../../extension-support/argument-type');
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const BlockType = require('../../extension-support/block-type');
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const Clone = require('../../util/clone');
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const log = require('../../util/log');
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const Video = require('../../io/video');
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const VideoMotion = require('./library');
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@ -34,39 +34,6 @@ class Scratch3VideoSensingBlocks {
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*/
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this._lastUpdate = null;
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/**
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* Id representing a Scratch Renderer skin the video is rendered to for
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* previewing.
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* @type {number}
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*/
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this._skinId = -1;
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/**
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* The Scratch Renderer Skin object.
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* @type {Skin}
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*/
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this._skin = null;
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/**
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* Id for a drawable using the video's skin that will render as a video
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* preview.
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* @type {Drawable}
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*/
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this._drawable = -1;
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/**
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* Canvas DOM element video is rendered to down or up sample to the
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* expected resolution.
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* @type {HTMLCanvasElement}
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*/
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this._sampleCanvas = null;
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/**
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* Canvas 2D Context to render to the _sampleCanvas member.
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* @type {CanvasRenderingContext2D}
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*/
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this._sampleContext = null;
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if (this.runtime.ioDevices) {
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// Clear target motion state values when the project starts.
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this.runtime.on(Runtime.PROJECT_RUN_START, this.reset.bind(this));
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@ -74,10 +41,11 @@ class Scratch3VideoSensingBlocks {
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// Boot up the video, canvas to down/up sample the video stream, the
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// preview skin and drawable, and kick off looping the analysis
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// logic.
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this._setupVideo();
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this._setupSampleCanvas();
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this._setupPreview();
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this._loop();
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this.runtime.ioDevices.video.requestVideo()
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.then(({release}) => {
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this.releaseVideo = release;
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this._loop();
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});
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}
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}
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@ -99,14 +67,6 @@ class Scratch3VideoSensingBlocks {
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return [480, 360];
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}
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/**
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* Order preview drawable is inserted at in the renderer.
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* @type {number}
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*/
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static get ORDER () {
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return 1;
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}
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/**
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* The key to load & store a target's motion-related state.
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* @type {string}
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@ -145,127 +105,30 @@ class Scratch3VideoSensingBlocks {
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}
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}
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/**
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* Setup a video element connected to a user media stream.
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* @private
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*/
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_setupVideo () {
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this._video = document.createElement('video');
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navigator.getUserMedia({
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audio: false,
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video: {
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width: {min: 480, ideal: 640},
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height: {min: 360, ideal: 480}
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}
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}, stream => {
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this._video.src = window.URL.createObjectURL(stream);
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// Hint to the stream that it should load. A standard way to do this
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// is add the video tag to the DOM. Since this extension wants to
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// hide the video tag and instead render a sample of the stream into
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// the webgl rendered Scratch canvas, another hint like this one is
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// needed.
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this._track = stream.getTracks()[0];
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}, err => {
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// @todo Properly handle errors
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log(err);
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});
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}
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/**
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* Create a campus to render the user media video to down/up sample to the
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* needed resolution.
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* @private
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*/
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_setupSampleCanvas () {
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// Create low-resolution image to sample video for analysis and preview
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const canvas = this._sampleCanvas = document.createElement('canvas');
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canvas.width = Scratch3VideoSensingBlocks.DIMENSIONS[0];
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canvas.height = Scratch3VideoSensingBlocks.DIMENSIONS[1];
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this._sampleContext = canvas.getContext('2d');
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}
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/**
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* Create a Scratch Renderer Skin and Drawable to preview the user media
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* video stream.
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* @private
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*/
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_setupPreview () {
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if (this._skinId !== -1) return;
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if (this._skin !== null) return;
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if (this._drawable !== -1) return;
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if (!this.runtime.renderer) return;
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this._skinId = this.runtime.renderer.createPenSkin();
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this._skin = this.runtime.renderer._allSkins[this._skinId];
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this._drawable = this.runtime.renderer.createDrawable();
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this.runtime.renderer.setDrawableOrder(
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this._drawable,
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Scratch3VideoSensingBlocks.ORDER
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);
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this.runtime.renderer.updateDrawableProperties(this._drawable, {
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skinId: this._skinId
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});
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}
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/**
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* Occasionally step a loop to sample the video, stamp it to the preview
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* skin, and add a TypedArray copy of the canvas's pixel data.
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* @private
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*/
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_loop () {
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setTimeout(this._loop.bind(this), this.runtime.currentStepTime);
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// Ensure video stream is established
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if (!this._video) return;
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if (!this._track) return;
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if (typeof this._video.videoWidth !== 'number') return;
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if (typeof this._video.videoHeight !== 'number') return;
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// Bail if the camera is *still* not ready
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const nativeWidth = this._video.videoWidth;
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const nativeHeight = this._video.videoHeight;
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if (nativeWidth === 0) return;
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if (nativeHeight === 0) return;
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const ctx = this._sampleContext;
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// Mirror
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ctx.scale(-1, 1);
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// Generate video thumbnail for analysis
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ctx.drawImage(
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this._video,
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0,
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0,
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nativeWidth,
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nativeHeight,
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Scratch3VideoSensingBlocks.DIMENSIONS[0] * -1,
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0,
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Scratch3VideoSensingBlocks.DIMENSIONS[0],
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Scratch3VideoSensingBlocks.DIMENSIONS[1]
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);
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// Restore the canvas transform
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ctx.resetTransform();
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// Render to preview layer
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if (this._skin !== null) {
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const xOffset = Scratch3VideoSensingBlocks.DIMENSIONS[0] / 2 * -1;
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const yOffset = Scratch3VideoSensingBlocks.DIMENSIONS[1] / 2;
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this._skin.drawStamp(this._sampleCanvas, xOffset, yOffset);
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this.runtime.requestRedraw();
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}
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setTimeout(this._loop.bind(this), Math.max(this.runtime.currentStepTime, Scratch3VideoSensingBlocks.INTERVAL));
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// Add frame to detector
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const time = Date.now();
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if (this._lastUpdate === null) this._lastUpdate = time;
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if (this._lastUpdate === null) {
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this._lastUpdate = time;
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}
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const offset = time - this._lastUpdate;
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if (offset > Scratch3VideoSensingBlocks.INTERVAL) {
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this._lastUpdate = time;
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const data = ctx.getImageData(
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0, 0, Scratch3VideoSensingBlocks.DIMENSIONS[0], Scratch3VideoSensingBlocks.DIMENSIONS[1]
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);
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this.detect.addFrame(data.data);
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const frame = this.runtime.ioDevices.video.getFrame({
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mirror: true,
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format: Video.FORMAT_IMAGE_DATA,
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dimensions: Scratch3VideoSensingBlocks.DIMENSIONS
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});
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if (frame) {
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this._lastUpdate = time;
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this.detect.addFrame(frame.data);
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}
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}
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}
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332
src/io/video.js
Normal file
332
src/io/video.js
Normal file
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@ -0,0 +1,332 @@
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const log = require('../util/log');
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class Video {
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constructor (runtime) {
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/**
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* Reference to the owning Runtime.
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* @type{!Runtime}
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*/
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this.runtime = runtime;
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/**
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* Cache frames for this many ms.
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* @type number
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*/
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this._frameCacheTimeout = 16;
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/**
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* Store each request for video, so when all are released we can disable preview/video feed.
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* @type Array.<object>
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*/
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this._requests = [];
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/**
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* DOM Video element
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* @private
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*/
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this._video = null;
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/**
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* Usermedia stream track
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* @private
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*/
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this._track = null;
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/**
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* Stores some canvas/frame data per resolution/mirror states
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*/
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this._workspace = [];
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/**
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* Id representing a Scratch Renderer skin the video is rendered to for
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* previewing.
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* @type {number}
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*/
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this._skinId = -1;
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/**
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* The Scratch Renderer Skin object.
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* @type {Skin}
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*/
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this._skin = null;
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/**
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* Id for a drawable using the video's skin that will render as a video
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* preview.
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* @type {Drawable}
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*/
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this._drawable = -1;
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}
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static get FORMAT_IMAGE_DATA () {
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return 'image-data';
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}
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static get FORMAT_CANVAS () {
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return 'canvas';
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}
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/**
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* Dimensions the video stream is analyzed at after its rendered to the
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* sample canvas.
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* @type {Array.<number>}
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*/
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static get DIMENSIONS () {
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return [480, 360];
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}
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/**
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* Order preview drawable is inserted at in the renderer.
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* @type {number}
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*/
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static get ORDER () {
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return 1;
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}
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/**
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* Request video be enabled. Sets up video, creates video skin and enables preview.
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*
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* ioDevices.video.requestVideo()
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* .then(({ release }) => {
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* this.releaseVideo = release;
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* })
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*
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* @return {Promise.<VideoRequest>} A request object with a "release" property that
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* should be called when you are done with the video.
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*/
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requestVideo () {
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const io = this;
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const request = {
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release () {
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const index = io._requests.indexOf(request);
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if (index > -1) {
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io._requests.splice(index, 1);
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}
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if (io._requests.length === 0) {
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io._disablePreview();
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// by clearing refs to video and track, we should lose our hold over the camera
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io._video = null;
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io._track = null;
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}
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}
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};
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if (this.videoReady) {
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this._requests.push(request);
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return Promise.resolve(request);
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}
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if (this._lastSetup) {
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return this._lastSetup.then(() => {
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this._requests.push(request);
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return request;
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});
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}
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this._lastSetup = this._setupVideo()
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.then(() => {
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this._setupPreview();
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this._requests.push(request);
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this._lastSetup = null;
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return request;
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}, err => {
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this._lastSetup = null;
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throw err;
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});
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return this._lastSetup;
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}
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/**
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* Create a video stream.
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* Should probably be moved to -render or somewhere similar later
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* @private
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* @return {Promise} When video has been received, rejected if video is not received
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*/
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_setupVideo () {
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this._video = document.createElement('video');
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return new Promise((resolve, reject) => {
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navigator.getUserMedia({
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audio: false,
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video: {
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width: {min: 480, ideal: 640},
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height: {min: 360, ideal: 480}
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}
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}, stream => {
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this._video.src = window.URL.createObjectURL(stream);
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// Hint to the stream that it should load. A standard way to do this
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// is add the video tag to the DOM. Since this extension wants to
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// hide the video tag and instead render a sample of the stream into
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// the webgl rendered Scratch canvas, another hint like this one is
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// needed.
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this._track = stream.getTracks()[0];
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resolve(this._video);
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}, err => {
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// There are probably some error types we could handle gracefully here.
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reject(err);
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});
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});
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}
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_disablePreview () {
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if (this._skin) {
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this._skin.clear();
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}
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this._renderPreviewFrame = null;
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}
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_setupPreview () {
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const {renderer} = this.runtime;
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if (!renderer) return;
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if (this._skinId === -1 && this._skin === null && this._drawable === -1) {
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this._skinId = renderer.createPenSkin();
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this._skin = renderer._allSkins[this._skinId];
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this._drawable = renderer.createDrawable();
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renderer.setDrawableOrder(
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this._drawable,
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Video.ORDER
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);
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renderer.updateDrawableProperties(this._drawable, {
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skinId: this._skinId
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});
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}
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// if we haven't already created and started a preview frame render loop, do so
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if (!this._renderPreviewFrame) {
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this._renderPreviewFrame = () => {
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if (!this._renderPreviewFrame) {
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return;
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}
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setTimeout(this._renderPreviewFrame, this.runtime.currentStepTime);
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const canvas = this.getFrame({format: Video.FORMAT_CANVAS});
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if (!canvas) {
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return;
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}
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const xOffset = Video.DIMENSIONS[0] / -2;
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const yOffset = Video.DIMENSIONS[1] / 2;
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this._skin.drawStamp(canvas, xOffset, yOffset);
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this.runtime.requestRedraw();
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};
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this._renderPreviewFrame();
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}
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}
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get videoReady () {
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if (!this._video) {
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return false;
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}
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if (!this._track) {
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return false;
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}
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const {videoWidth, videoHeight} = this._video;
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if (typeof videoWidth !== 'number' || typeof videoHeight !== 'number') {
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return false;
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}
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if (videoWidth === 0 || videoHeight === 0) {
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return false;
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}
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return true;
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}
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/**
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* get an internal workspace for canvas/context/caches
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* this uses some document stuff to create a canvas and what not, probably needs abstraction
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* into the renderer layer?
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* @private
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* @return {object} A workspace for canvas/data storage. Internal format not documented intentionally
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*/
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_getWorkspace ({dimensions, mirror}) {
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let workspace = this._workspace.find(space => (
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space.dimensions.join('-') === dimensions.join('-') &&
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space.mirror === mirror
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));
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if (!workspace) {
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workspace = {
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dimensions,
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mirror,
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canvas: document.createElement('canvas'),
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lastUpdate: 0,
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cacheData: {}
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};
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workspace.canvas.width = dimensions[0];
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workspace.canvas.height = dimensions[1];
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workspace.context = workspace.canvas.getContext('2d');
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this._workspace.push(workspace);
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}
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return workspace;
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}
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/**
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* Return frame data from the video feed in a specified dimensions, format, and mirroring.
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* @return {ArrayBuffer|Canvas|string|null} Frame data in requested format, null when errors.
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*/
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getFrame ({
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dimensions = Video.DIMENSIONS,
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mirror = true,
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format = Video.FORMAT_IMAGE_DATA,
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cacheTimeout = this._frameCacheTimeout
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}) {
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if (!this.videoReady) {
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return null;
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}
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const [width, height] = dimensions;
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const workspace = this._getWorkspace({dimensions, mirror: Boolean(mirror)});
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const {videoWidth, videoHeight} = this._video;
|
||||
const {canvas, context, lastUpdate, cacheData} = workspace;
|
||||
const now = Date.now();
|
||||
|
||||
// if the canvas hasn't been updated...
|
||||
if (lastUpdate + cacheTimeout < now) {
|
||||
|
||||
if (mirror) {
|
||||
context.scale(-1, 1);
|
||||
context.translate(width * -1, 0);
|
||||
}
|
||||
|
||||
context.drawImage(this._video,
|
||||
// source x, y, width, height
|
||||
0, 0, videoWidth, videoHeight,
|
||||
// dest x, y, width, height
|
||||
0, 0, width, height
|
||||
);
|
||||
|
||||
context.resetTransform();
|
||||
workspace.lastUpdate = now;
|
||||
}
|
||||
|
||||
// each data type has it's own data cache, but the canvas is the same
|
||||
if (!cacheData[format]) {
|
||||
cacheData[format] = {lastUpdate: 0};
|
||||
}
|
||||
const formatCache = cacheData[format];
|
||||
|
||||
if (formatCache.lastUpdate + cacheTimeout < now) {
|
||||
if (format === Video.FORMAT_IMAGE_DATA) {
|
||||
formatCache.lastData = context.getImageData(0, 0, width, height);
|
||||
} else if (format === Video.FORMAT_CANVAS) {
|
||||
// this will never change
|
||||
formatCache.lastUpdate = Infinity;
|
||||
formatCache.lastData = canvas;
|
||||
} else {
|
||||
log.error(`video io error - unimplemented format ${format}`);
|
||||
// cache the null result forever, don't log about it again..
|
||||
formatCache.lastUpdate = Infinity;
|
||||
formatCache.lastData = null;
|
||||
}
|
||||
|
||||
// rather than set to now, this data is as stale as it's canvas is
|
||||
formatCache.lastUpdate = Math.max(workspace.lastUpdate, formatCache.lastUpdate);
|
||||
}
|
||||
|
||||
return formatCache.lastData;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
module.exports = Video;
|
||||
Loading…
Reference in a new issue