files_photospheres/js/marzipano/VideoAsset.js

129 строки
3.6 KiB
JavaScript

/*
* Copyright 2016 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// Dynamic asset containing a video element.
//
// The wrappedVideo argument should be an object exposing two methods:
// - videoElement() returning the actual HTML video element;
// - drawElement() returning the HTML element to be used as a WebGL texture.
//
// The two available implementations are NullVideoElementWrapper and
// CanvasHackVideoElementWrapper. See the respective files for an explanation.
function VideoAsset(wrappedVideo) {
this._wrappedVideo = null;
this._destroyed = false;
this._emitChange = this.emit.bind(this, 'change');
this._lastTimestamp = -1;
this.setVideo(wrappedVideo);
this.emptyCanvas = document.createElement('canvas');
this.emptyCanvas.width = 1;
this.emptyCanvas.height = 1;
}
Marzipano.dependencies.eventEmitter(VideoAsset);
VideoAsset.prototype.setVideo = function(wrappedVideo) {
var self = this;
this._wrappedVideo = wrappedVideo;
if (this._wrappedVideo) {
this._wrappedVideo.videoElement().removeEventListener('timeupdate', this._emitChange);
}
if (wrappedVideo == null) {
return;
}
var videoElement = wrappedVideo.videoElement();
videoElement.addEventListener('timeupdate', this._emitChange);
// Emit a change event on every frame while the video is playing.
// TODO: make the loop sleep when video is not playing.
if (this._emitChangeIfPlayingLoop) {
cancelAnimationFrame(this._emitChangeIfPlayingLoop);
this._emitChangeIfPlayingLoop = null;
}
function emitChangeIfPlaying() {
if (!videoElement.paused) {
self.emit('change');
}
if (!self._destroyed) {
self._emitChangeIfPlayingLoop = requestAnimationFrame(emitChangeIfPlaying);
}
}
emitChangeIfPlaying();
this.emit('change');
};
VideoAsset.prototype.width = function() {
if (this._wrappedVideo) {
return this._wrappedVideo.videoElement().videoWidth;
} else {
return this.emptyCanvas.width;
}
};
VideoAsset.prototype.height = function() {
if (this._wrappedVideo) {
return this._wrappedVideo.videoElement().videoHeight;
} else {
return this.emptyCanvas.height;
}
};
VideoAsset.prototype.element = function() {
// If element is null, show an empty canvas. This will cause a transparent
// image to be rendered when no video is present.
if (this._wrappedVideo) {
return this._wrappedVideo.drawElement();
} else {
return this.emptyCanvas;
}
};
VideoAsset.prototype.video = function() {
return this._wrappedVideo;
};
VideoAsset.prototype.isDynamic = function() {
return true;
};
VideoAsset.prototype.timestamp = function() {
if (this._wrappedVideo) {
this._lastTimestamp = this._wrappedVideo.videoElement().currentTime;
}
return this._lastTimestamp;
};
VideoAsset.prototype.destroy = function() {
this._destroyed = true;
if (this._wrappedVideo) {
this._wrappedVideo.videoElement().removeEventListener('timeupdate', this._emitChange);
}
if (this._emitChangeIfPlayingLoop) {
cancelAnimationFrame(this._emitChangeIfPlayingLoop);
this._emitChangeIfPlayingLoop = null;
}
};