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https://saranat.fi/wp-content/plugins/wpvr-pro/lib/pannellum/src/js/libpannellum.js

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1/*
2 * libpannellum - A WebGL and CSS 3D transform based Panorama Renderer
3 * Copyright (c) 2012-2019 Matthew Petroff
4 * 
5 * Permission is hereby granted, free of charge, to any person obtaining a copy
6 * of this software and associated documentation files (the "Software"), to deal
7 * in the Software without restriction, including without limitation the rights
8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 * copies of the Software, and to permit persons to whom the Software is
10 * furnished to do so, subject to the following conditions:
11 * 
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 * 
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 * THE SOFTWARE.
22 */
23
24window.libpannellum = (function(window, document, undefined) {
25
26'use strict';
27
28/**
29 * Creates a new panorama renderer.
30 * @constructor
31 * @param {HTMLElement} container - The container element for the renderer.
32 */
33function Renderer(container) {
34    var canvas = document.createElement('canvas');
35    canvas.style.width = canvas.style.height = '100%';
36    container.appendChild(canvas);
37
38    var program, gl, vs, fs;
39    var fallbackImgSize;
40    var world;
41    var vtmps;
42    var pose;
43    var image, imageType, dynamic;
44    var texCoordBuffer, cubeVertBuf, cubeVertTexCoordBuf, cubeVertIndBuf;
45    var globalParams;
46
47    /**
48     * Initialize renderer.
49     * @memberof Renderer
50     * @instance
51     * @param {Image|Array|Object} image - Input image; format varies based on
52     *      `imageType`. For `equirectangular`, this is an image; for
53     *      `cubemap`, this is an array of images for the cube faces in the
54     *      order [+z, +x, -z, -x, +y, -y]; for `multires`, this is a
55     *      configuration object.
56     * @param {string} imageType - The type of the image: `equirectangular`,
57     *      `cubemap`, or `multires`.
58     * @param {boolean} dynamic - Whether or not the image is dynamic (e.g. video).
59     * @param {number} haov - Initial horizontal angle of view.
60     * @param {number} vaov - Initial vertical angle of view.
61     * @param {number} voffset - Initial vertical offset angle.
62     * @param {function} callback - Load callback function.
63     * @param {Object} [params] - Other configuration parameters (`horizonPitch`, `horizonRoll`, `backgroundColor`).
64     */
65    this.init = function(_image, _imageType, _dynamic, haov, vaov, voffset, callback, params) {
66        // Default argument for image type
67        if (_imageType === undefined)
68            _imageType = 'equirectangular';
69
70        if (_imageType != 'equirectangular' && _imageType != 'cubemap' &&
71            _imageType != 'multires') {
72            console.log('Error: invalid image type specified!');
73            throw {type: 'config error'};
74        }
75
76        imageType = _imageType;
77        image = _image;
78        dynamic = _dynamic;
79        globalParams = params || {};
80
81        // Clear old data
82        if (program) {
83            if (vs) {
84                gl.detachShader(program, vs);
85                gl.deleteShader(vs);
86            }
87            if (fs) {
88                gl.detachShader(program, fs);
89                gl.deleteShader(fs);
90            }
91            gl.bindBuffer(gl.ARRAY_BUFFER, null);
92            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null);
93            if (program.texture)
94                gl.deleteTexture(program.texture);
95            if (program.nodeCache)
96                for (var i = 0; i < program.nodeCache.length; i++)
97                    gl.deleteTexture(program.nodeCache[i].texture);
98            gl.deleteProgram(program);
99            program = undefined;
100        }
101        pose = undefined;
102
103        var s;
104        var faceMissing = false;
105        var cubeImgWidth;
106        if (imageType == 'cubemap') {
107            for (s = 0; s < 6; s++) {
108                if (image[s].width > 0) {
109                    if (cubeImgWidth === undefined)
110                        cubeImgWidth = image[s].width;
111                    if (cubeImgWidth != image[s].width)
112                        console.log('Cube faces have inconsistent widths: ' + cubeImgWidth + ' vs. ' + image[s].width);
113                } else
114                    faceMissing = true;
115            }
116        }
117        function fillMissingFaces(imgSize) {
118            if (faceMissing) { // Fill any missing fallback/cubemap faces with background
119                var nbytes = imgSize * imgSize * 4; // RGB, plus non-functional alpha
120                var imageArray = new Uint8ClampedArray(nbytes);
121                var rgb = params.backgroundColor ? params.backgroundColor : [0, 0, 0];
122                rgb[0] *= 255;
123                rgb[1] *= 255;
124                rgb[2] *= 255;
125                // Maybe filling could be done faster, see e.g. https://stackoverflow.com/questions/1295584/most-efficient-way-to-create-a-zero-filled-javascript-array
126                for (var i = 0; i < nbytes; i++) {
127                    imageArray[i++] = rgb[0];
128                    imageArray[i++] = rgb[1];
129                    imageArray[i++] = rgb[2];
130                }
131                var backgroundSquare = new ImageData(imageArray, imgSize, imgSize);
132                for (s = 0; s < 6; s++) {
133                    if (image[s].width == 0)
134                        image[s] = backgroundSquare;
135                }
136            }
137        }
138        
139        // This awful browser specific test exists because iOS 8/9 and IE 11
140        // don't display non-power-of-two cubemap textures but also don't
141        // throw an error (tested on an iPhone 5c / iOS 8.1.3 / iOS 9.2 /
142        // iOS 10.3.1).
143        // Therefore, the WebGL context is never created for these browsers for
144        // NPOT cubemaps, and the CSS 3D transform fallback renderer is used
145        // instead.
146        if (!(imageType == 'cubemap' &&
147            (cubeImgWidth & (cubeImgWidth - 1)) !== 0 &&
148            (navigator.userAgent.toLowerCase().match(/(iphone|ipod|ipad).* os 8_/) ||
149            navigator.userAgent.toLowerCase().match(/(iphone|ipod|ipad).* os 9_/) ||
150            navigator.userAgent.toLowerCase().match(/(iphone|ipod|ipad).* os 10_/) ||
151            navigator.userAgent.match(/Trident.*rv[ :]*11\./)))) {
152            // Enable WebGL on canvas
153            if (!gl)
154                gl = canvas.getContext('experimental-webgl', {alpha: false, depth: false});
155            if (gl && gl.getError() == 1286)
156                handleWebGLError1286();
157        }
158        
159        // If there is no WebGL, fall back to CSS 3D transform renderer.
160        // This will discard the image loaded so far and load the fallback image.
161        // While browser specific tests are usually frowned upon, the
162        // fallback viewer only really works with WebKit/Blink and IE 10/11
163        // (it doesn't work properly in Firefox).
164        if (!gl && ((imageType == 'multires' && image.hasOwnProperty('fallbackPath')) ||
165            imageType == 'cubemap') &&
166            ('WebkitAppearance' in document.documentElement.style ||
167            navigator.userAgent.match(/Trident.*rv[ :]*11\./) ||
168            navigator.appVersion.indexOf('MSIE 10') !== -1)) {
169            // Remove old world if it exists
170            if (world) {
171                container.removeChild(world);
172            }
173            
174            // Initialize renderer
175            world = document.createElement('div');
176            world.className = 'pnlm-world';
177            
178            // Add images
179            var path;
180            if (image.basePath) {
181                path = image.basePath + image.fallbackPath;
182            } else {
183                path = image.fallbackPath;
184            }
185            var sides = ['f', 'r', 'b', 'l', 'u', 'd'];
186            var loaded = 0;
187            var onLoad = function() {
188                // Draw image on canvas
189                var faceCanvas = document.createElement('canvas');
190                faceCanvas.className = 'pnlm-face pnlm-' + sides[this.side] + 'face';
191                world.appendChild(faceCanvas);
192                var faceContext = faceCanvas.getContext('2d');
193                faceCanvas.style.width = this.width + 4 + 'px';
194                faceCanvas.style.height = this.height + 4 + 'px';
195                faceCanvas.width = this.width + 4;
196                faceCanvas.height = this.height + 4;
197                faceContext.drawImage(this, 2, 2);
198                var imgData = faceContext.getImageData(0, 0, faceCanvas.width, faceCanvas.height);
199                var data = imgData.data;
200                
201                // Duplicate edge pixels
202                var i;
203                var j;
204                for (i = 2; i < faceCanvas.width - 2; i++) {
205                    for (j = 0; j < 4; j++) {
206                        data[(i + faceCanvas.width) * 4 + j] = data[(i + faceCanvas.width * 2) * 4 + j];
207                        data[(i + faceCanvas.width * (faceCanvas.height - 2)) * 4 + j] = data[(i + faceCanvas.width * (faceCanvas.height - 3)) * 4 + j];
208                    }
209                }
210                for (i = 2; i < faceCanvas.height - 2; i++) {
211                    for (j = 0; j < 4; j++) {
212                        data[(i * faceCanvas.width + 1) * 4 + j] = data[(i * faceCanvas.width + 2) * 4 + j];
213                        data[((i + 1) * faceCanvas.width - 2) * 4 + j] = data[((i + 1) * faceCanvas.width - 3) * 4 + j];
214                    }
215                }
216                for (j = 0; j < 4; j++) {
217                    data[(faceCanvas.width + 1) * 4 + j] = data[(faceCanvas.width * 2 + 2) * 4 + j];
218                    data[(faceCanvas.width * 2 - 2) * 4 + j] = data[(faceCanvas.width * 3 - 3) * 4 + j];
219                    data[(faceCanvas.width * (faceCanvas.height - 2) + 1) * 4 + j] = data[(faceCanvas.width * (faceCanvas.height - 3) + 2) * 4 + j];
220                    data[(faceCanvas.width * (faceCanvas.height - 1) - 2) * 4 + j] = data[(faceCanvas.width * (faceCanvas.height - 2) - 3) * 4 + j];
221                }
222                for (i = 1; i < faceCanvas.width - 1; i++) {
223                    for (j = 0; j < 4; j++) {
224                        data[i * 4 + j] = data[(i + faceCanvas.width) * 4 + j];
225                        data[(i + faceCanvas.width * (faceCanvas.height - 1)) * 4 + j] = data[(i + faceCanvas.width * (faceCanvas.height - 2)) * 4 + j];
226                    }
227                }
228                for (i = 1; i < faceCanvas.height - 1; i++) {
229                    for (j = 0; j < 4; j++) {
230                        data[(i * faceCanvas.width) * 4 + j] = data[(i * faceCanvas.width + 1) * 4 + j];
231                        data[((i + 1) * faceCanvas.width - 1) * 4 + j] = data[((i + 1) * faceCanvas.width - 2) * 4 + j];
232                    }
233                }
234                for (j = 0; j < 4; j++) {
235                    data[j] = data[(faceCanvas.width + 1) * 4 + j];
236                    data[(faceCanvas.width - 1) * 4 + j] = data[(faceCanvas.width * 2 - 2) * 4 + j];
237                    data[(faceCanvas.width * (faceCanvas.height - 1)) * 4 + j] = data[(faceCanvas.width * (faceCanvas.height - 2) + 1) * 4 + j];
238                    data[(faceCanvas.width * faceCanvas.height - 1) * 4 + j] = data[(faceCanvas.width * (faceCanvas.height - 1) - 2) * 4 + j];
239                }
240                
241                // Draw image width duplicated edge pixels on canvas
242                faceContext.putImageData(imgData, 0, 0);
243                
244                incLoaded.call(this);
245            };
246            var incLoaded = function() {
247                if (this.width > 0) {
248                    if (fallbackImgSize === undefined)
249                        fallbackImgSize = this.width;
250                    if (fallbackImgSize != this.width)
251                        console.log('Fallback faces have inconsistent widths: ' + fallbackImgSize + ' vs. ' + this.width);
252                } else
253                    faceMissing = true;
254                loaded++;
255                if (loaded == 6) {
256                    fallbackImgSize = this.width;
257                    container.appendChild(world);
258                    callback();
259                }
260            };
261            faceMissing = false;
262            for (s = 0; s < 6; s++) {
263                var faceImg = new Image();
264                faceImg.crossOrigin = globalParams.crossOrigin ? globalParams.crossOrigin : 'anonymous';
265                faceImg.side = s;
266                faceImg.onload = onLoad;
267                faceImg.onerror = incLoaded; // ignore missing face to support partial fallback image
268                if (imageType == 'multires') {
269                    faceImg.src = path.replace('%s', sides[s]) + '.' + image.extension;
270                } else {
271                    faceImg.src = image[s].src;
272                }
273            }
274            fillMissingFaces(fallbackImgSize);
275            return;
276        } else if (!gl) {
277            console.log('Error: no WebGL support detected!');
278            throw {type: 'no webgl'};
279        }
280        if (imageType == 'cubemap')
281            fillMissingFaces(cubeImgWidth);
282        if (image.basePath) {
283            image.fullpath = image.basePath + image.path;
284        } else {
285            image.fullpath = image.path;
286        }
287        image.invTileResolution = 1 / image.tileResolution;
288        
289        var vertices = createCube();
290        vtmps = [];
291        for (s = 0; s < 6; s++) {
292            vtmps[s] = vertices.slice(s * 12, s * 12 + 12);
293            vertices = createCube();
294        }
295        
296        // Make sure image isn't too big
297        var maxWidth = 0;
298        if (imageType == 'equirectangular') {
299            maxWidth = gl.getParameter(gl.MAX_TEXTURE_SIZE);
300            if (Math.max(image.width / 2, image.height) > maxWidth) {
301                console.log('Error: The image is too big; it\'s ' + image.width + 'px wide, '+
302                            'but this device\'s maximum supported size is ' + (maxWidth * 2) + 'px.');
303                throw {type: 'webgl size error', width: image.width, maxWidth: maxWidth * 2};
304            }
305        } else if (imageType == 'cubemap') {
306            if (cubeImgWidth > gl.getParameter(gl.MAX_CUBE_MAP_TEXTURE_SIZE)) {
307                console.log('Error: The image is too big; it\'s ' + cubeImgWidth + 'px wide, ' +
308                            'but this device\'s maximum supported size is ' + maxWidth + 'px.');
309                throw {type: 'webgl size error', width: cubeImgWidth, maxWidth: maxWidth};
310            }
311        }
312
313        // Store horizon pitch and roll if applicable
314        if (params !== undefined && (params.horizonPitch !== undefined || params.horizonRoll !== undefined))
315            pose = [params.horizonPitch == undefined ? 0 : params.horizonPitch,
316                    params.horizonRoll == undefined ? 0 : params.horizonRoll];
317
318        // Set 2d texture binding
319        var glBindType = gl.TEXTURE_2D;
320
321        // Create viewport for entire canvas
322        gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
323
324        // Check precision support
325        if (gl.getShaderPrecisionFormat) {
326            var precision = gl.getShaderPrecisionFormat(gl.FRAGMENT_SHADER, gl.HIGH_FLOAT);
327            if (precision && precision.precision < 1) {
328                // `highp` precision not supported; https://stackoverflow.com/a/33308927
329                fragEquiCubeBase = fragEquiCubeBase.replace('highp', 'mediump');
330            }
331        }
332
333        // Create vertex shader
334        vs = gl.createShader(gl.VERTEX_SHADER);
335        var vertexSrc = v;
336        if (imageType == 'multires') {
337            vertexSrc = vMulti;
338        }
339        gl.shaderSource(vs, vertexSrc);
340        gl.compileShader(vs);
341
342        // Create fragment shader
343        fs = gl.createShader(gl.FRAGMENT_SHADER);
344        var fragmentSrc = fragEquirectangular;
345        if (imageType == 'cubemap') {
346            glBindType = gl.TEXTURE_CUBE_MAP;
347            fragmentSrc = fragCube;
348        } else if (imageType == 'multires') {
349            fragmentSrc = fragMulti;
350        }
351        gl.shaderSource(fs, fragmentSrc);
352        gl.compileShader(fs);
353
354        // Link WebGL program
355        program = gl.createProgram();
356        gl.attachShader(program, vs);
357        gl.attachShader(program, fs);
358        gl.linkProgram(program);
359
360        // Log errors
361        if (!gl.getShaderParameter(vs, gl.COMPILE_STATUS))
362            console.log(gl.getShaderInfoLog(vs));
363        if (!gl.getShaderParameter(fs, gl.COMPILE_STATUS))
364            console.log(gl.getShaderInfoLog(fs));
365        if (!gl.getProgramParameter(program, gl.LINK_STATUS))
366            console.log(gl.getProgramInfoLog(program));
367
368        // Use WebGL program
369        gl.useProgram(program);
370
371        program.drawInProgress = false;
372
373        // Set background clear color (does not apply to cubemap/fallback image)
374        var color = params.backgroundColor ? params.backgroundColor : [0, 0, 0];
375        gl.clearColor(color[0], color[1], color[2], 1.0);
376        gl.clear(gl.COLOR_BUFFER_BIT);
377
378        // Look up texture coordinates location
379        program.texCoordLocation = gl.getAttribLocation(program, 'a_texCoord');
380        gl.enableVertexAttribArray(program.texCoordLocation);
381
382        if (imageType != 'multires') {
383            // Provide texture coordinates for rectangle
384            if (!texCoordBuffer)
385                texCoordBuffer = gl.createBuffer();
386            gl.bindBuffer(gl.ARRAY_BUFFER, texCoordBuffer);
387            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([-1,1,1,1,1,-1,-1,1,1,-1,-1,-1]), gl.STATIC_DRAW);
388            gl.vertexAttribPointer(program.texCoordLocation, 2, gl.FLOAT, false, 0, 0);
389
390            // Pass aspect ratio
391            program.aspectRatio = gl.getUniformLocation(program, 'u_aspectRatio');
392            gl.uniform1f(program.aspectRatio, gl.drawingBufferWidth / gl.drawingBufferHeight);
393
394            // Locate psi, theta, focal length, horizontal extent, vertical extent, and vertical offset
395            program.psi = gl.getUniformLocation(program, 'u_psi');
396            program.theta = gl.getUniformLocation(program, 'u_theta');
397            program.f = gl.getUniformLocation(program, 'u_f');
398            program.h = gl.getUniformLocation(program, 'u_h');
399            program.v = gl.getUniformLocation(program, 'u_v');
400            program.vo = gl.getUniformLocation(program, 'u_vo');
401            program.rot = gl.getUniformLocation(program, 'u_rot');
402
403            // Pass horizontal extent, vertical extent, and vertical offset
404            gl.uniform1f(program.h, haov / (Math.PI * 2.0));
405            gl.uniform1f(program.v, vaov / Math.PI);
406            gl.uniform1f(program.vo, voffset / Math.PI * 2);
407
408            // Set background color
409            if (imageType == 'equirectangular') {
410                program.backgroundColor = gl.getUniformLocation(program, 'u_backgroundColor');
411                gl.uniform4fv(program.backgroundColor, color.concat([1]));
412            }
413
414            // Create texture
415            program.texture = gl.createTexture();
416            gl.bindTexture(glBindType, program.texture);
417
418            // Upload images to texture depending on type
419            if (imageType == 'cubemap') {
420                // Load all six sides of the cube map
421                gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_X, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image[1]);
422                gl.texImage2D(gl.TEXTURE_CUBE_MAP_NEGATIVE_X, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image[3]);
423                gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_Y, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image[4]);
424                gl.texImage2D(gl.TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image[5]);
425                gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_Z, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image[0]);
426                gl.texImage2D(gl.TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image[2]);
427            } else {
428                if (image.width <= maxWidth) {
429                    gl.uniform1i(gl.getUniformLocation(program, 'u_splitImage'), 0);
430                    // Upload image to the texture
431                    gl.texImage2D(glBindType, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image);
432                } else {
433                    // Image needs to be split into two parts due to texture size limits
434                    gl.uniform1i(gl.getUniformLocation(program, 'u_splitImage'), 1);
435
436                    // Draw image on canvas
437                    var cropCanvas = document.createElement('canvas');
438                    cropCanvas.width = image.width / 2;
439                    cropCanvas.height = image.height;
440                    var cropContext = cropCanvas.getContext('2d');
441                    cropContext.drawImage(image, 0, 0);
442
443                    // Upload first half of image to the texture
444                    var cropImage = cropContext.getImageData(0, 0, image.width / 2, image.height);
445                    gl.texImage2D(glBindType, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, cropImage);
446
447                    // Create and bind texture for second half of image
448                    program.texture2 = gl.createTexture();
449                    gl.activeTexture(gl.TEXTURE1);
450                    gl.bindTexture(glBindType, program.texture2);
451                    gl.uniform1i(gl.getUniformLocation(program, 'u_image1'), 1);
452
453                    // Upload second half of image to the texture
454                    cropContext.drawImage(image, -image.width / 2, 0);
455                    cropImage = cropContext.getImageData(0, 0, image.width / 2, image.height);
456                    gl.texImage2D(glBindType, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, cropImage);
457
458                    // Set parameters for rendering any size
459                    gl.texParameteri(glBindType, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
460                    gl.texParameteri(glBindType, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
461                    gl.texParameteri(glBindType, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
462                    gl.texParameteri(glBindType, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
463
464                    // Reactivate first texture unit
465                    gl.activeTexture(gl.TEXTURE0);
466                }
467            }
468
469            // Set parameters for rendering any size
470            gl.texParameteri(glBindType, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
471            gl.texParameteri(glBindType, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
472            gl.texParameteri(glBindType, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
473            gl.texParameteri(glBindType, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
474
475        } else {
476            // Look up vertex coordinates location
477            program.vertPosLocation = gl.getAttribLocation(program, 'a_vertCoord');
478            gl.enableVertexAttribArray(program.vertPosLocation);
479
480            // Create buffers
481            if (!cubeVertBuf)
482                cubeVertBuf = gl.createBuffer();
483            if (!cubeVertTexCoordBuf)
484                cubeVertTexCoordBuf = gl.createBuffer();
485            if (!cubeVertIndBuf)
486                cubeVertIndBuf = gl.createBuffer();
487
488            // Bind texture coordinate buffer and pass coordinates to WebGL
489            gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertTexCoordBuf);
490            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([0,0,1,0,1,1,0,1]), gl.STATIC_DRAW);
491
492            // Bind square index buffer and pass indicies to WebGL
493            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, cubeVertIndBuf);
494            gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array([0,1,2,0,2,3]), gl.STATIC_DRAW);
495
496            // Find uniforms
497            program.perspUniform = gl.getUniformLocation(program, 'u_perspMatrix');
498            program.cubeUniform = gl.getUniformLocation(program, 'u_cubeMatrix');
499            //program.colorUniform = gl.getUniformLocation(program, 'u_color');
500
501            program.level = -1;
502
503            program.currentNodes = [];
504            program.nodeCache = [];
505            program.nodeCacheTimestamp = 0;
506        }
507
508        // Check if there was an error
509        var err = gl.getError();
510        if (err !== 0) {
511            console.log('Error: Something went wrong with WebGL!', err);
512            throw {type: 'webgl error'};
513        }
514
515        callback();
516     };
517
518    /**
519     * Destroy renderer.
520     * @memberof Renderer
521     * @instance
522     */
523    this.destroy = function() {
524        if (container !== undefined) {
525            if (canvas !== undefined && container.contains(canvas)) {
526                container.removeChild(canvas);
527            }
528            if (world !== undefined && container.contains(world)) {
529                container.removeChild(world);
530            }
531        }
532        if (gl) {
533            // The spec says this is only supposed to simulate losing the WebGL
534            // context, but in practice it tends to actually free the memory.
535            var extension = gl.getExtension('WEBGL_lose_context');
536            if (extension)
537                extension.loseContext();
538        }
539    };
540
541    /**
542     * Resize renderer (call after resizing container).
543     * @memberof Renderer
544     * @instance
545     */
546    this.resize = function() {
547        var pixelRatio = window.devicePixelRatio || 1;
548        canvas.width = canvas.clientWidth * pixelRatio;
549        canvas.height = canvas.clientHeight * pixelRatio;
550        if (gl) {
551            if (gl.getError() == 1286)
552                handleWebGLError1286();
553            gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
554            if (imageType != 'multires') {
555                gl.uniform1f(program.aspectRatio, canvas.clientWidth / canvas.clientHeight);
556            }
557        }
558    };
559    // Initialize canvas size
560    this.resize();
561
562    /**
563     * Set renderer horizon pitch and roll.
564     * @memberof Renderer
565     * @instance
566     */
567    this.setPose = function(horizonPitch, horizonRoll) {
568        pose = [horizonPitch, horizonRoll];
569    };
570
571    /**
572     * Render new view of panorama.
573     * @memberof Renderer
574     * @instance
575     * @param {number} pitch - Pitch to render at (in radians).
576     * @param {number} yaw - Yaw to render at (in radians).
577     * @param {number} hfov - Horizontal field of view to render with (in radians).
578     * @param {Object} [params] - Extra configuration parameters. 
579     * @param {number} [params.roll] - Camera roll (in radians).
580     * @param {boolean} [params.returnImage] - Return rendered image?
581     */
582    this.render = function(pitch, yaw, hfov, params) {
583        var focal, i, s, roll = 0;
584        if (params === undefined)
585            params = {};
586        if (params.roll)
587            roll = params.roll;
588
589        // Apply pitch and roll transformation if applicable
590        if (pose !== undefined) {
591            var horizonPitch = pose[0],
592                horizonRoll = pose[1];
593
594            // Calculate new pitch and yaw
595            var orig_pitch = pitch,
596                orig_yaw = yaw,
597                x = Math.cos(horizonRoll) * Math.sin(pitch) * Math.sin(horizonPitch) +
598                    Math.cos(pitch) * (Math.cos(horizonPitch) * Math.cos(yaw) +
599                    Math.sin(horizonRoll) * Math.sin(horizonPitch) * Math.sin(yaw)),
600                y = -Math.sin(pitch) * Math.sin(horizonRoll) +
601                    Math.cos(pitch) * Math.cos(horizonRoll) * Math.sin(yaw),
602                z = Math.cos(horizonRoll) * Math.cos(horizonPitch) * Math.sin(pitch) +
603                    Math.cos(pitch) * (-Math.cos(yaw) * Math.sin(horizonPitch) +
604                    Math.cos(horizonPitch) * Math.sin(horizonRoll) * Math.sin(yaw));
605            pitch = Math.asin(Math.max(Math.min(z, 1), -1));
606            yaw = Math.atan2(y, x);
607
608            // Calculate roll
609            var v = [Math.cos(orig_pitch) * (Math.sin(horizonRoll) * Math.sin(horizonPitch) * Math.cos(orig_yaw) -
610                    Math.cos(horizonPitch) * Math.sin(orig_yaw)),
611                    Math.cos(orig_pitch) * Math.cos(horizonRoll) * Math.cos(orig_yaw),
612                    Math.cos(orig_pitch) * (Math.cos(horizonPitch) * Math.sin(horizonRoll) * Math.cos(orig_yaw) +
613                    Math.sin(orig_yaw) * Math.sin(horizonPitch))],
614                w = [-Math.cos(pitch) * Math.sin(yaw), Math.cos(pitch) * Math.cos(yaw)];
615            var roll_adj = Math.acos(Math.max(Math.min((v[0]*w[0] + v[1]*w[1]) /
616                (Math.sqrt(v[0]*v[0]+v[1]*v[1]+v[2]*v[2]) *
617                Math.sqrt(w[0]*w[0]+w[1]*w[1])), 1), -1));
618            if (v[2] < 0)
619                roll_adj = 2 * Math.PI - roll_adj;
620            roll += roll_adj;
621        }
622
623        // If no WebGL
624        if (!gl && (imageType == 'multires' || imageType == 'cubemap')) {
625            // Determine face transforms
626            s = fallbackImgSize / 2;
627            
628            var transforms = {
629                f: 'translate3d(-' + (s + 2) + 'px, -' + (s + 2) + 'px, -' + s + 'px)',
630                b: 'translate3d(' + (s + 2) + 'px, -' + (s + 2) + 'px, ' + s + 'px) rotateX(180deg) rotateZ(180deg)',
631                u: 'translate3d(-' + (s + 2) + 'px, -' + s + 'px, ' + (s + 2) + 'px) rotateX(270deg)',
632                d: 'translate3d(-' + (s + 2) + 'px, ' + s + 'px, -' + (s + 2) + 'px) rotateX(90deg)',
633                l: 'translate3d(-' + s + 'px, -' + (s + 2) + 'px, ' + (s + 2) + 'px) rotateX(180deg) rotateY(90deg) rotateZ(180deg)',
634                r: 'translate3d(' + s + 'px, -' + (s + 2) + 'px, -' + (s + 2) + 'px) rotateY(270deg)'
635            };
636            focal = 1 / Math.tan(hfov / 2);
637            var zoom = focal * canvas.clientWidth / 2 + 'px';
638            var transform = 'perspective(' + zoom + ') translateZ(' + zoom + ') rotateX(' + pitch + 'rad) rotateY(' + yaw + 'rad) ';
639            
640            // Apply face transforms
641            var faces = Object.keys(transforms);
642            for (i = 0; i < 6; i++) {
643                var face = world.querySelector('.pnlm-' + faces[i] + 'face');
644                if (!face)
645                    continue; // ignore missing face to support partial cubemap/fallback image
646                face.style.webkitTransform = transform + transforms[faces[i]];
647                face.style.transform = transform + transforms[faces[i]];
648            }
649            return;
650        }
651        
652        if (imageType != 'multires') {
653            // Calculate focal length from vertical field of view
654            var vfov = 2 * Math.atan(Math.tan(hfov * 0.5) / (gl.drawingBufferWidth / gl.drawingBufferHeight));
655            focal = 1 / Math.tan(vfov * 0.5);
656
657            // Pass psi, theta, roll, and focal length
658            gl.uniform1f(program.psi, yaw);
659            gl.uniform1f(program.theta, pitch);
660            gl.uniform1f(program.rot, roll);
661            gl.uniform1f(program.f, focal);
662            
663            if (dynamic === true) {
664                // Update texture if dynamic
665                if (imageType == 'equirectangular') {
666                    gl.bindTexture(gl.TEXTURE_2D, program.texture);
667                    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image);
668                }
669            }
670            
671            // Draw using current buffer
672            gl.drawArrays(gl.TRIANGLES, 0, 6);
673        
674        } else {
675            // Create perspective matrix
676            var perspMatrix = makePersp(hfov, gl.drawingBufferWidth / gl.drawingBufferHeight, 0.1, 100.0);
677            
678            // Find correct zoom level
679            checkZoom(hfov);
680            
681            // Create rotation matrix
682            var matrix = identityMatrix3();
683            matrix = rotateMatrix(matrix, -roll, 'z');
684            matrix = rotateMatrix(matrix, -pitch, 'x');
685            matrix = rotateMatrix(matrix, yaw, 'y');
686            matrix = makeMatrix4(matrix);
687            
688            // Set matrix uniforms
689            gl.uniformMatrix4fv(program.perspUniform, false, new Float32Array(transposeMatrix4(perspMatrix)));
690            gl.uniformMatrix4fv(program.cubeUniform, false, new Float32Array(transposeMatrix4(matrix)));
691            
692            // Find current nodes
693            var rotPersp = rotatePersp(perspMatrix, matrix);
694            program.nodeCache.sort(multiresNodeSort);
695            if (program.nodeCache.length > 200 &&
696                program.nodeCache.length > program.currentNodes.length + 50) {
697                // Remove older nodes from cache
698                var removed = program.nodeCache.splice(200, program.nodeCache.length - 200);
699                for (var j = 0; j < removed.length; j++) {
700                    // Explicitly delete textures
701                    gl.deleteTexture(removed[j].texture);
702                }
703            }
704            program.currentNodes = [];
705            
706            var sides = ['f', 'b', 'u', 'd', 'l', 'r'];
707            for (s = 0; s < 6; s++) {
708                var ntmp = new MultiresNode(vtmps[s], sides[s], 1, 0, 0, image.fullpath);
709                testMultiresNode(rotPersp, ntmp, pitch, yaw, hfov);
710            }
711            
712            program.currentNodes.sort(multiresNodeRenderSort);
713            
714            // Unqueue any pending requests for nodes that are no longer visible
715            for (i = pendingTextureRequests.length - 1; i >= 0; i--) {
716                if (program.currentNodes.indexOf(pendingTextureRequests[i].node) === -1) {
717                    pendingTextureRequests[i].node.textureLoad = false;
718                    pendingTextureRequests.splice(i, 1);
719                }
720            }
721            
722            // Allow one request to be pending, so that we can create a texture buffer for that in advance of loading actually beginning
723            if (pendingTextureRequests.length === 0) {
724                for (i = 0; i < program.currentNodes.length; i++) {
725                    var node = program.currentNodes[i];
726                    if (!node.texture && !node.textureLoad) {
727                        node.textureLoad = true;
728            
729                        setTimeout(processNextTile, 0, node);
730                        
731                        // Only process one tile per frame to improve responsiveness
732                        break;
733                    }
734                }
735            }
736            
737            // Draw tiles
738            multiresDraw();
739        }
740        
741        if (params.returnImage !== undefined) {
742            return canvas.toDataURL('image/png');
743        }
744    };
745    
746    /**
747     * Check if images are loading.
748     * @memberof Renderer
749     * @instance
750     * @returns {boolean} Whether or not images are loading.
751     */
752    this.isLoading = function() {
753        if (gl && imageType == 'multires') {
754            for ( var i = 0; i < program.currentNodes.length; i++ ) {
755                if (!program.currentNodes[i].textureLoaded) {
756                    return true;
757                }
758            }
759        }
760        return false;
761    };
762    
763    /**
764     * Retrieve renderer's canvas.
765     * @memberof Renderer
766     * @instance
767     * @returns {HTMLElement} Renderer's canvas.
768     */
769    this.getCanvas = function() {
770        return canvas;
771    };
772    
773    /**
774     * Sorting method for multires nodes.
775     * @private
776     * @param {MultiresNode} a - First node.
777     * @param {MultiresNode} b - Second node.
778     * @returns {number} Base tiles first, then higher timestamp first.
779     */
780    function multiresNodeSort(a, b) {
781        // Base tiles are always first
782        if (a.level == 1 && b.level != 1) {
783            return -1;
784        }
785        if (b. level == 1 && a.level != 1) {
786            return 1;
787        }
788        
789        // Higher timestamp first
790        return b.timestamp - a.timestamp;
791    }
792    
793    /**
794     * Sorting method for multires node rendering.
795     * @private
796     * @param {MultiresNode} a - First node.
797     * @param {MultiresNode} b - Second node.
798     * @returns {number} Lower zoom levels first, then closest to center first.
799     */
800    function multiresNodeRenderSort(a, b) {
801        // Lower zoom levels first
802        if (a.level != b.level) {
803            return a.level - b.level;
804        }
805        
806        // Lower distance from center first
807        return a.diff - b.diff;
808    }
809    
810    /**
811     * Draws multires nodes.
812     * @private
813     */
814    function multiresDraw() {
815        if (!program.drawInProgress) {
816            program.drawInProgress = true;
817            gl.clear(gl.COLOR_BUFFER_BIT);
818            for ( var i = 0; i < program.currentNodes.length; i++ ) {
819                if (program.currentNodes[i].textureLoaded > 1) {
820                    //var color = program.currentNodes[i].color;
821                    //gl.uniform4f(program.colorUniform, color[0], color[1], color[2], 1.0);
822                    
823                    // Bind vertex buffer and pass vertices to WebGL
824                    gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertBuf);
825                    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(program.currentNodes[i].vertices), gl.STATIC_DRAW);
826                    gl.vertexAttribPointer(program.vertPosLocation, 3, gl.FLOAT, false, 0, 0);
827                    
828                    // Prep for texture
829                    gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertTexCoordBuf);
830                    gl.vertexAttribPointer(program.texCoordLocation, 2, gl.FLOAT, false, 0, 0);
831                    
832                    // Bind texture and draw tile
833                    gl.bindTexture(gl.TEXTURE_2D, program.currentNodes[i].texture); // Bind program.currentNodes[i].texture to TEXTURE0
834                    gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
835                }
836            }
837            program.drawInProgress = false;
838        }
839    }
840
841    /**
842     * Creates new multires node.
843     * @constructor
844     * @private
845     * @param {number[]} vertices - Node's verticies.
846     * @param {string} side - Node's cube face.
847     * @param {number} level - Node's zoom level.
848     * @param {number} x - Node's x position.
849     * @param {number} y - Node's y position.
850     * @param {string} path - Node's path.
851     */
852    function MultiresNode(vertices, side, level, x, y, path) {
853        this.vertices = vertices;
854        this.side = side;
855        this.level = level;
856        this.x = x;
857        this.y = y;
858        this.path = path.replace('%s',side).replace('%l',level).replace('%x',x).replace('%y',y);
859    }
860
861    /**
862     * Test if multires node is visible. If it is, add it to current nodes,
863     * load its texture, and load appropriate child nodes.
864     * @private
865     * @param {number[]} rotPersp - Rotated perspective matrix.
866     * @param {MultiresNode} node - Multires node to check.
867     * @param {number} pitch - Pitch to check at.
868     * @param {number} yaw - Yaw to check at.
869     * @param {number} hfov - Horizontal field of view to check at.
870     */
871    function testMultiresNode(rotPersp, node, pitch, yaw, hfov) {
872        if (checkSquareInView(rotPersp, node.vertices)) {
873            // Calculate central angle between center of view and center of tile
874            var v = node.vertices;
875            var x = v[0] + v[3] + v[6] + v[ 9];
876            var y = v[1] + v[4] + v[7] + v[10];
877            var z = v[2] + v[5] + v[8] + v[11];
878            var r = Math.sqrt(x*x + y*y + z*z);
879            var theta = Math.asin(z / r);
880            var phi = Math.atan2(y, x);
881            var ydiff = phi - yaw;
882            ydiff += (ydiff > Math.PI) ? -2 * Math.PI : (ydiff < -Math.PI) ? 2 * Math.PI : 0;
883            ydiff = Math.abs(ydiff);
884            node.diff = Math.acos(Math.sin(pitch) * Math.sin(theta) + Math.cos(pitch) * Math.cos(theta) * Math.cos(ydiff));
885            
886            // Add node to current nodes and load texture if needed
887            var inCurrent = false;
888            for (var k = 0; k < program.nodeCache.length; k++) {
889                if (program.nodeCache[k].path == node.path) {
890                    inCurrent = true;
891                    program.nodeCache[k].timestamp = program.nodeCacheTimestamp++;
892                    program.nodeCache[k].diff = node.diff;
893                    program.currentNodes.push(program.nodeCache[k]);
894                    break;
895                }
896            }
897            if (!inCurrent) {
898                //node.color = [Math.random(), Math.random(), Math.random()];
899                node.timestamp = program.nodeCacheTimestamp++;
900                program.currentNodes.push(node);
901                program.nodeCache.push(node);
902            }
903            
904            // TODO: Test error
905            // Create child nodes
906            if (node.level < program.level) {
907                var cubeSize = image.cubeResolution * Math.pow(2, node.level - image.maxLevel);
908                var numTiles = Math.ceil(cubeSize * image.invTileResolution) - 1;
909                var doubleTileSize = cubeSize % image.tileResolution * 2;
910                var lastTileSize = (cubeSize * 2) % image.tileResolution;
911                if (lastTileSize === 0) {
912                    lastTileSize = image.tileResolution;
913                }
914                if (doubleTileSize === 0) {
915                    doubleTileSize = image.tileResolution * 2;
916                }
917                var f = 0.5;
918                if (node.x == numTiles || node.y == numTiles) {
919                    f = 1.0 - image.tileResolution / (image.tileResolution + lastTileSize);
920                }
921                var i = 1.0 - f;
922                var children = [];
923                var vtmp, ntmp;
924                var f1 = f, f2 = f, f3 = f, i1 = i, i2 = i, i3 = i;
925                // Handle non-symmetric tiles
926                if (lastTileSize < image.tileResolution) {
927                    if (node.x == numTiles && node.y != numTiles) {
928                        f2 = 0.5;
929                        i2 = 0.5;
930                        if (node.side == 'd' || node.side == 'u') {
931                            f3 = 0.5;
932                            i3 = 0.5;
933                        }
934                    } else if (node.x != numTiles && node.y == numTiles) {
935                        f1 = 0.5;
936                        i1 = 0.5;
937                        if (node.side == 'l' || node.side == 'r') {
938                            f3 = 0.5;
939                            i3 = 0.5;
940                        }
941                    }
942                }
943                // Handle small tiles that have fewer than four children
944                if (doubleTileSize <= image.tileResolution) {
945                    if (node.x == numTiles) {
946                        f1 = 0;
947                        i1 = 1;
948                        if (node.side == 'l' || node.side == 'r') {
949                            f3 = 0;
950                            i3 = 1;
951                        }
952                    }
953                    if (node.y == numTiles) {
954                        f2 = 0;
955                        i2 = 1;
956                        if (node.side == 'd' || node.side == 'u') {
957                            f3 = 0;
958                            i3 = 1;
959                        }
960                    }
961                }
962                
963                vtmp = [           v[0],             v[1],             v[2],
964                        v[0]*f1+v[3]*i1,    v[1]*f+v[4]*i,  v[2]*f3+v[5]*i3,
965                        v[0]*f1+v[6]*i1,  v[1]*f2+v[7]*i2,  v[2]*f3+v[8]*i3,
966                          v[0]*f+v[9]*i, v[1]*f2+v[10]*i2, v[2]*f3+v[11]*i3
967                ];
968                ntmp = new MultiresNode(vtmp, node.side, node.level + 1, node.x*2, node.y*2, image.fullpath);
969                children.push(ntmp);
970                if (!(node.x == numTiles && doubleTileSize <= image.tileResolution)) {
971                    vtmp = [v[0]*f1+v[3]*i1,    v[1]*f+v[4]*i,  v[2]*f3+v[5]*i3,
972                                       v[3],             v[4],             v[5],
973                              v[3]*f+v[6]*i,  v[4]*f2+v[7]*i2,  v[5]*f3+v[8]*i3,
974                            v[0]*f1+v[6]*i1,  v[1]*f2+v[7]*i2,  v[2]*f3+v[8]*i3
975                    ];
976                    ntmp = new MultiresNode(vtmp, node.side, node.level + 1, node.x*2+1, node.y*2, image.fullpath);
977                    children.push(ntmp);
978                }
979                if (!(node.x == numTiles && doubleTileSize <= image.tileResolution) &&
980                    !(node.y == numTiles && doubleTileSize <= image.tileResolution)) {
981                    vtmp = [v[0]*f1+v[6]*i1,  v[1]*f2+v[7]*i2,  v[2]*f3+v[8]*i3,
982                              v[3]*f+v[6]*i,  v[4]*f2+v[7]*i2,  v[5]*f3+v[8]*i3,
983                                       v[6],             v[7],             v[8],
984                            v[9]*f1+v[6]*i1,   v[10]*f+v[7]*i, v[11]*f3+v[8]*i3
985                    ];
986                    ntmp = new MultiresNode(vtmp, node.side, node.level + 1, node.x*2+1, node.y*2+1, image.fullpath);
987                    children.push(ntmp);
988                }
989                if (!(node.y == numTiles && doubleTileSize <= image.tileResolution)) {
990                    vtmp = [  v[0]*f+v[9]*i, v[1]*f2+v[10]*i2, v[2]*f3+v[11]*i3,
991                            v[0]*f1+v[6]*i1,  v[1]*f2+v[7]*i2,  v[2]*f3+v[8]*i3,
992                            v[9]*f1+v[6]*i1,   v[10]*f+v[7]*i, v[11]*f3+v[8]*i3,
993                                       v[9],            v[10],            v[11]
994                    ];
995                    ntmp = new MultiresNode(vtmp, node.side, node.level + 1, node.x*2, node.y*2+1, image.fullpath);
996                    children.push(ntmp);
997                }
998                for (var j = 0; j < children.length; j++) {
999                    testMultiresNode(rotPersp, children[j], pitch, yaw, hfov);
1000                }
1001            }
1002        }
1003    }
1004    
1005    /**
1006     * Creates cube vertex array.
1007     * @private
1008     * @returns {number[]} Cube vertex array.
1009     */
1010    function createCube() {
1011        return [-1,  1, -1,  1,  1, -1,  1, -1, -1, -1, -1, -1, // Front face
1012                 1,  1,  1, -1,  1,  1, -1, -1,  1,  1, -1,  1, // Back face
1013                -1,  1,  1,  1,  1,  1,  1,  1, -1, -1,  1, -1, // Up face
1014                -1, -1, -1,  1, -1, -1,  1, -1,  1, -1, -1,  1, // Down face
1015                -1,  1,  1, -1,  1, -1, -1, -1, -1, -1, -1,  1, // Left face
1016                 1,  1, -1,  1,  1,  1,  1, -1,  1,  1, -1, -1  // Right face
1017        ];
1018    }
1019    
1020    /**
1021     * Creates 3x3 identity matrix.
1022     * @private
1023     * @returns {number[]} Identity matrix.
1024     */
1025    function identityMatrix3() {
1026        return [
1027            1, 0, 0,
1028            0, 1, 0,
1029            0, 0, 1
1030        ];
1031    }
1032    
1033    /**
1034     * Rotates a 3x3 matrix.
1035     * @private
1036     * @param {number[]} m - Matrix to rotate.
1037     * @param {number[]} angle - Angle to rotate by in radians.
1038     * @param {string} axis - Axis to rotate about (`x`, `y`, or `z`).
1039     * @returns {number[]} Rotated matrix.
1040     */
1041    function rotateMatrix(m, angle, axis) {
1042        var s = Math.sin(angle);
1043        var c = Math.cos(angle);
1044        if (axis == 'x') {
1045            return [
1046                m[0], c*m[1] + s*m[2], c*m[2] - s*m[1],
1047                m[3], c*m[4] + s*m[5], c*m[5] - s*m[4],
1048                m[6], c*m[7] + s*m[8], c*m[8] - s*m[7]
1049            ];
1050        }
1051        if (axis == 'y') {
1052            return [
1053                c*m[0] - s*m[2], m[1], c*m[2] + s*m[0],
1054                c*m[3] - s*m[5], m[4], c*m[5] + s*m[3],
1055                c*m[6] - s*m[8], m[7], c*m[8] + s*m[6]
1056            ];
1057        }
1058        if (axis == 'z') {
1059            return [
1060                c*m[0] + s*m[1], c*m[1] - s*m[0], m[2],
1061                c*m[3] + s*m[4], c*m[4] - s*m[3], m[5],
1062                c*m[6] + s*m[7], c*m[7] - s*m[6], m[8]
1063            ];
1064        }
1065    }
1066    
1067    /**
1068     * Turns a 3x3 matrix into a 4x4 matrix.
1069     * @private
1070     * @param {number[]} m - Input matrix.
1071     * @returns {number[]} Expanded matrix.
1072     */
1073    function makeMatrix4(m) {
1074        return [
1075            m[0], m[1], m[2],    0,
1076            m[3], m[4], m[5],    0,
1077            m[6], m[7], m[8],    0,
1078               0,    0,    0,    1
1079        ];
1080    }
1081    
1082    /**
1083     * Transposes a 4x4 matrix.
1084     * @private
1085     * @param {number[]} m - Input matrix.
1086     * @returns {number[]} Transposed matrix.
1087     */
1088    function transposeMatrix4(m) {
1089        return [
1090            m[ 0], m[ 4], m[ 8], m[12],
1091            m[ 1], m[ 5], m[ 9], m[13],
1092            m[ 2], m[ 6], m[10], m[14],
1093            m[ 3], m[ 7], m[11], m[15]
1094        ];
1095    }
1096    
1097    /**
1098     * Creates a perspective matrix.
1099     * @private
1100     * @param {number} hfov - Desired horizontal field of view.
1101     * @param {number} aspect - Desired aspect ratio.
1102     * @param {number} znear - Near distance.
1103     * @param {number} zfar - Far distance.
1104     * @returns {number[]} Generated perspective matrix.
1105     */
1106    function makePersp(hfov, aspect, znear, zfar) {
1107        var fovy = 2 * Math.atan(Math.tan(hfov/2) * gl.drawingBufferHeight / gl.drawingBufferWidth);
1108        var f = 1 / Math.tan(fovy/2);
1109        return [
1110            f/aspect,   0,  0,  0,
1111                   0,   f,  0,  0,
1112                   0,   0,  (zfar+znear)/(znear-zfar), (2*zfar*znear)/(znear-zfar),
1113                   0,   0, -1,  0
1114        ];
1115    }
1116    
1117    /**
1118     * Processes a loaded texture image into a WebGL texture.
1119     * @private
1120     * @param {Image} img - Input image.
1121     * @param {WebGLTexture} tex - Texture to bind image to.
1122     */
1123    function processLoadedTexture(img, tex) {
1124        gl.bindTexture(gl.TEXTURE_2D, tex);
1125        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, img);
1126        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
1127        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
1128        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
1129        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
1130        gl.bindTexture(gl.TEXTURE_2D, null);
1131    }
1132    
1133    var pendingTextureRequests = [];
1134
1135    // Based on http://blog.tojicode.com/2012/03/javascript-memory-optimization-and.html
1136    var loadTexture = (function() {
1137        var cacheTop = 4;   // Maximum number of concurrents loads
1138        var textureImageCache = {};
1139        var crossOrigin;
1140
1141        function TextureImageLoader() {
1142            var self = this;
1143            this.texture = this.callback = null;
1144            this.image = new Image();
1145            this.image.crossOrigin = crossOrigin ? crossOrigin : 'anonymous';
1146            var loadFn = (function() {
1147                if (self.image.width > 0 && self.image.height > 0) { // ignore missing tile to supporting partial image
1148                    processLoadedTexture(self.image, self.texture);
1149                    self.callback(self.texture, true);
1150                } else {
1151                    self.callback(self.texture, false);
1152                }
1153                releaseTextureImageLoader(self);
1154            });
1155            this.image.addEventListener('load', loadFn);
1156            this.image.addEventListener('error', loadFn); // ignore missing tile file to support partial image, otherwise retry loop causes high CPU load
1157        }
1158
1159        TextureImageLoader.prototype.loadTexture = function(src, texture, callback) {
1160            this.texture = texture;
1161            this.callback = callback;
1162            this.image.src = src;
1163        };
1164
1165        function PendingTextureRequest(node, src, texture, callback) {
1166            this.node = node;
1167            this.src = src;
1168            this.texture = texture;
1169            this.callback = callback;
1170        }
1171
1172        function releaseTextureImageLoader(til) {
1173            if (pendingTextureRequests.length) {
1174                var req = pendingTextureRequests.shift();
1175                til.loadTexture(req.src, req.texture, req.callback);
1176            } else
1177                textureImageCache[cacheTop++] = til;
1178        }
1179
1180        for (var i = 0; i < cacheTop; i++)
1181            textureImageCache[i] = new TextureImageLoader();
1182
1183        return function(node, src, callback, _crossOrigin) {
1184            crossOrigin = _crossOrigin;
1185            var texture = gl.createTexture();
1186            if (cacheTop)
1187                textureImageCache[--cacheTop].loadTexture(src, texture, callback);
1188            else
1189                pendingTextureRequests.push(new PendingTextureRequest(node, src, texture, callback));
1190            return texture;
1191        };
1192    })();
1193
1194    /**
1195     * Loads image and creates texture for a multires node / tile.
1196     * @private
1197     * @param {MultiresNode} node - Input node.
1198     */
1199    function processNextTile(node) {
1200        loadTexture(node, node.path + '.' + image.extension, function(texture, loaded) {
1201            node.texture = texture;
1202            node.textureLoaded = loaded ? 2 : 1;
1203        }, globalParams.crossOrigin);
1204    }
1205    
1206    /**
1207     * Finds and applies optimal multires zoom level.
1208     * @private
1209     * @param {number} hfov - Horizontal field of view to check at.
1210     */
1211    function checkZoom(hfov) {
1212        // Find optimal level
1213        var newLevel = 1;
1214        while ( newLevel < image.maxLevel &&
1215            gl.drawingBufferWidth > image.tileResolution *
1216            Math.pow(2, newLevel - 1) * Math.tan(hfov / 2) * 0.707 ) {
1217            newLevel++;
1218        }
1219        
1220        // Apply change
1221        program.level = newLevel;
1222    }
1223    
1224    /**
1225     * Rotates perspective matrix.
1226     * @private
1227     * @param {number[]} p - Perspective matrix.
1228     * @param {number[]} r - Rotation matrix.
1229     * @returns {number[]} Rotated matrix.
1230     */
1231    function rotatePersp(p, r) {
1232        return [
1233            p[ 0]*r[0], p[ 0]*r[1], p[ 0]*r[ 2],     0,
1234            p[ 5]*r[4], p[ 5]*r[5], p[ 5]*r[ 6],     0,
1235            p[10]*r[8], p[10]*r[9], p[10]*r[10], p[11],
1236                 -r[8],      -r[9],      -r[10],     0
1237        ];
1238    }
1239    
1240    /**
1241     * Applies rotated perspective matrix to a 3-vector
1242     * (last element is inverted).
1243     * @private
1244     * @param {number[]} m - Rotated perspective matrix.
1245     * @param {number[]} v - Input 3-vector.
1246     * @returns {number[]} Resulting 4-vector.
1247     */
1248    function applyRotPerspToVec(m, v) {
1249        return [
1250                    m[ 0]*v[0] + m[ 1]*v[1] + m[ 2]*v[2],
1251                    m[ 4]*v[0] + m[ 5]*v[1] + m[ 6]*v[2],
1252            m[11] + m[ 8]*v[0] + m[ 9]*v[1] + m[10]*v[2],
1253                 1/(m[12]*v[0] + m[13]*v[1] + m[14]*v[2])
1254        ];
1255    }
1256    
1257    /**
1258     * Checks if a vertex is visible.
1259     * @private
1260     * @param {number[]} m - Rotated perspective matrix.
1261     * @param {number[]} v - Input vertex.
1262     * @returns {number} 1 or -1 if the vertex is or is not visible,
1263     *      respectively.
1264     */
1265    function checkInView(m, v) {
1266        var vpp = applyRotPerspToVec(m, v);
1267        var winX = vpp[0]*vpp[3];
1268        var winY = vpp[1]*vpp[3];
1269        var winZ = vpp[2]*vpp[3];
1270        var ret = [0, 0, 0];
1271        
1272        if ( winX < -1 )
1273            ret[0] = -1;
1274        if ( winX > 1 )
1275            ret[0] = 1;
1276        if ( winY < -1 )
1277            ret[1] = -1;
1278        if ( winY > 1 )
1279            ret[1] = 1;
1280        if ( winZ < -1 || winZ > 1 )
1281            ret[2] = 1;
1282        return ret;
1283    }
1284    
1285    /**
1286     * Checks if a square (tile) is visible.
1287     * @private
1288     * @param {number[]} m - Rotated perspective matrix.
1289     * @param {number[]} v - Square's vertex array.
1290     * @returns {boolean} Whether or not the square is visible.
1291     */
1292    function checkSquareInView(m, v) {
1293        var check1 = checkInView(m, v.slice(0, 3));
1294        var check2 = checkInView(m, v.slice(3, 6));
1295        var check3 = checkInView(m, v.slice(6, 9));
1296        var check4 = checkInView(m, v.slice(9, 12));
1297        var testX = check1[0] + check2[0] + check3[0] + check4[0];
1298        if ( testX == -4 || testX == 4 )
1299            return false;
1300        var testY = check1[1] + check2[1] + check3[1] + check4[1];
1301        if ( testY == -4 || testY == 4 )
1302            return false;
1303        var testZ = check1[2] + check2[2] + check3[2] + check4[2];
1304        return testZ != 4;
1305        
1306
1307    }
1308
1309    /**
1310     * On iOS (iPhone 5c, iOS 10.3), this WebGL error occurs when the canvas is
1311     * too big. Unfortuately, there's no way to test for this beforehand, so we
1312     * reduce the canvas size if this error is thrown.
1313     * @private
1314     */
1315    function handleWebGLError1286() {
1316        console.log('Reducing canvas size due to error 1286!');
1317        canvas.width = Math.round(canvas.width / 2);
1318        canvas.height = Math.round(canvas.height / 2);
1319    }
1320}
1321
1322// Vertex shader for equirectangular and cube
1323var v = [
1324'attribute vec2 a_texCoord;',
1325'varying vec2 v_texCoord;',
1326
1327'void main() {',
1328    // Set position
1329    'gl_Position = vec4(a_texCoord, 0.0, 1.0);',
1330    
1331    // Pass the coordinates to the fragment shader
1332    'v_texCoord = a_texCoord;',
1333'}'
1334].join('');
1335
1336// Vertex shader for multires
1337var vMulti = [
1338'attribute vec3 a_vertCoord;',
1339'attribute vec2 a_texCoord;',
1340
1341'uniform mat4 u_cubeMatrix;',
1342'uniform mat4 u_perspMatrix;',
1343
1344'varying mediump vec2 v_texCoord;',
1345
1346'void main(void) {',
1347    // Set position
1348    'gl_Position = u_perspMatrix * u_cubeMatrix * vec4(a_vertCoord, 1.0);',
1349    
1350    // Pass the coordinates to the fragment shader
1351    'v_texCoord = a_texCoord;',
1352'}'
1353].join('');
1354
1355// Fragment shader
1356var fragEquiCubeBase = [
1357'precision highp float;', // mediump looks bad on some mobile devices
1358
1359'uniform float u_aspectRatio;',
1360'uniform float u_psi;',
1361'uniform float u_theta;',
1362'uniform float u_f;',
1363'uniform float u_h;',
1364'uniform float u_v;',
1365'uniform float u_vo;',
1366'uniform float u_rot;',
1367
1368'const float PI = 3.14159265358979323846264;',
1369
1370// Texture
1371'uniform sampler2D u_image0;',
1372'uniform sampler2D u_image1;',
1373'uniform bool u_splitImage;',
1374'uniform samplerCube u_imageCube;',
1375
1376// Coordinates passed in from vertex shader
1377'varying vec2 v_texCoord;',
1378
1379// Background color (display for partial panoramas)
1380'uniform vec4 u_backgroundColor;',
1381
1382'void main() {',
1383    // Map canvas/camera to sphere
1384    'float x = v_texCoord.x * u_aspectRatio;',
1385    'float y = v_texCoord.y;',
1386    'float sinrot = sin(u_rot);',
1387    'float cosrot = cos(u_rot);',
1388    'float rot_x = x * cosrot - y * sinrot;',
1389    'float rot_y = x * sinrot + y * cosrot;',
1390    'float sintheta = sin(u_theta);',
1391    'float costheta = cos(u_theta);',
1392    'float a = u_f * costheta - rot_y * sintheta;',
1393    'float root = sqrt(rot_x * rot_x + a * a);',
1394    'float lambda = atan(rot_x / root, a / root) + u_psi;',
1395    'float phi = atan((rot_y * costheta + u_f * sintheta) / root);',
1396].join('\n');
1397
1398// Fragment shader
1399var fragCube = fragEquiCubeBase + [
1400    // Look up color from texture
1401    'float cosphi = cos(phi);',
1402    'gl_FragColor = textureCube(u_imageCube, vec3(cosphi*sin(lambda), sin(phi), cosphi*cos(lambda)));',
1403'}'
1404].join('\n');
1405
1406// Fragment shader
1407var fragEquirectangular = fragEquiCubeBase + [
1408    // Wrap image
1409    'lambda = mod(lambda + PI, PI * 2.0) - PI;',
1410
1411    // Map texture to sphere
1412    'vec2 coord = vec2(lambda / PI, phi / (PI / 2.0));',
1413
1414    // Look up color from texture
1415    // Map from [-1,1] to [0,1] and flip y-axis
1416    'if(coord.x < -u_h || coord.x > u_h || coord.y < -u_v + u_vo || coord.y > u_v + u_vo)',
1417        'gl_FragColor = u_backgroundColor;',
1418    'else {',
1419        'if(u_splitImage) {',
1420            // Image was split into two textures to work around texture size limits
1421            'if(coord.x < 0.0)',
1422                'gl_FragColor = texture2D(u_image0, vec2((coord.x + u_h) / u_h, (-coord.y + u_v + u_vo) / (u_v * 2.0)));',
1423            'else',
1424                'gl_FragColor = texture2D(u_image1, vec2((coord.x + u_h) / u_h - 1.0, (-coord.y + u_v + u_vo) / (u_v * 2.0)));',
1425        '} else {',
1426            'gl_FragColor = texture2D(u_image0, vec2((coord.x + u_h) / (u_h * 2.0), (-coord.y + u_v + u_vo) / (u_v * 2.0)));',
1427        '}',
1428    '}',
1429'}'
1430].join('\n');
1431
1432// Fragment shader
1433var fragMulti = [
1434'varying mediump vec2 v_texCoord;',
1435'uniform sampler2D u_sampler;',
1436//'uniform mediump vec4 u_color;',
1437
1438'void main(void) {',
1439    // Look up color from texture
1440    'gl_FragColor = texture2D(u_sampler, v_texCoord);',
1441//    'gl_FragColor = u_color;',
1442'}'
1443].join('');
1444
1445return {
1446    renderer: function(container, image, imagetype, dynamic) {
1447        return new Renderer(container, image, imagetype, dynamic);
1448    }
1449};
1450
1451})(window, document);

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