src/viewer/scene/canvas/Canvas.js
import {math} from '../math/math.js';
import {Component} from '../Component.js';
import {Spinner} from './Spinner.js';
const WEBGL_CONTEXT_NAMES = [
"webgl2",
"experimental-webgl",
"webkit-3d",
"moz-webgl",
"moz-glweb20"
];
/**
* @desc Manages its {@link Scene}'s HTML canvas.
*
* * Provides the HTML canvas element in {@link Canvas#canvas}.
* * Has a {@link Spinner}, provided at {@link Canvas#spinner}, which manages the loading progress indicator.
*/
class Canvas extends Component {
/**
* @constructor
* @private
*/
constructor(owner, cfg = {}) {
super(owner, cfg);
this._backgroundColor = math.vec3([
cfg.backgroundColor ? cfg.backgroundColor[0] : 1,
cfg.backgroundColor ? cfg.backgroundColor[1] : 1,
cfg.backgroundColor ? cfg.backgroundColor[2] : 1]);
this._backgroundColorFromAmbientLight = !!cfg.backgroundColorFromAmbientLight;
/**
* The HTML canvas.
*
* @property canvas
* @type {HTMLCanvasElement}
* @final
*/
this.canvas = cfg.canvas;
/**
* The WebGL rendering context.
*
* @property gl
* @type {WebGLRenderingContext}
* @final
*/
this.gl = null;
/**
* True when WebGL 2 support is enabled.
*
* @property webgl2
* @type {Boolean}
* @final
*/
this.webgl2 = false; // Will set true in _initWebGL if WebGL is requested and we succeed in getting it.
/**
* Indicates if this Canvas is transparent.
*
* @property transparent
* @type {Boolean}
* @default {false}
* @final
*/
this.transparent = !!cfg.transparent;
/**
* Attributes for the WebGL context
*
* @type {{}|*}
*/
this.contextAttr = cfg.contextAttr || {};
this.contextAttr.alpha = this.transparent;
this.contextAttr.preserveDrawingBuffer = !!this.contextAttr.preserveDrawingBuffer;
this.contextAttr.stencil = false;
this.contextAttr.premultipliedAlpha = (!!this.contextAttr.premultipliedAlpha); // False by default: https://github.com/xeokit/xeokit-sdk/issues/251
this.contextAttr.antialias = (this.contextAttr.antialias !== false);
// If the canvas uses css styles to specify the sizes make sure the basic
// width and height attributes match or the WebGL context will use 300 x 150
this.resolutionScale = cfg.resolutionScale;
this.canvas.width = Math.round(this.canvas.clientWidth * this._resolutionScale);
this.canvas.height = Math.round(this.canvas.clientHeight * this._resolutionScale);
/**
* Boundary of the Canvas in absolute browser window coordinates.
*
* ### Usage:
*
* ````javascript
* var boundary = myScene.canvas.boundary;
*
* var xmin = boundary[0];
* var ymin = boundary[1];
* var width = boundary[2];
* var height = boundary[3];
* ````
*
* @property boundary
* @type {Number[]}
* @final
*/
this.boundary = [
this.canvas.offsetLeft, this.canvas.offsetTop,
this.canvas.clientWidth, this.canvas.clientHeight
];
// Get WebGL context
this._initWebGL(cfg);
// Bind context loss and recovery handlers
const self = this;
this.canvas.addEventListener("webglcontextlost", this._webglcontextlostListener = function (event) {
console.time("webglcontextrestored");
self.scene._webglContextLost();
/**
* Fired whenever the WebGL context has been lost
* @event webglcontextlost
*/
self.fire("webglcontextlost");
event.preventDefault();
},
false);
this.canvas.addEventListener("webglcontextrestored", this._webglcontextrestoredListener = function (event) {
self._initWebGL();
if (self.gl) {
self.scene._webglContextRestored(self.gl);
/**
* Fired whenever the WebGL context has been restored again after having previously being lost
* @event webglContextRestored
* @param value The WebGL context object
*/
self.fire("webglcontextrestored", self.gl);
event.preventDefault();
}
console.timeEnd("webglcontextrestored");
},
false);
// Attach to resize events on the canvas
let dirtyBoundary = true; // make sure we publish the 1st boundary event
const resizeObserver = new ResizeObserver((entries) => {
for (const entry of entries) {
if (entry.contentBoxSize) {
dirtyBoundary = true;
}
}
});
resizeObserver.observe(this.canvas);
// Publish canvas size and position changes on each scene tick
this._tick = this.scene.on("tick", () => {
// Only publish if the canvas bounds changed
if (!dirtyBoundary) {
return;
}
dirtyBoundary = false;
// Set the real size of the canvas (the drawable w*h)
self.canvas.width = Math.round(self.canvas.clientWidth * self._resolutionScale);
self.canvas.height = Math.round(self.canvas.clientHeight * self._resolutionScale);
// Publish the boundary change
self.boundary[0] = self.canvas.offsetLeft;
self.boundary[1] = self.canvas.offsetTop;
self.boundary[2] = self.canvas.clientWidth;
self.boundary[3] = self.canvas.clientHeight;
self.fire("boundary", self.boundary);
});
this._spinner = new Spinner(this.scene, {
canvas: this.canvas,
elementId: cfg.spinnerElementId
});
}
/**
@private
*/
get type() {
return "Canvas";
}
/**
* Gets whether the canvas clear color will be derived from {@link AmbientLight} or {@link Canvas#backgroundColor}
* when {@link Canvas#transparent} is ```true```.
*
* When {@link Canvas#transparent} is ```true``` and this is ````true````, then the canvas clear color will
* be taken from the {@link Scene}'s ambient light color.
*
* When {@link Canvas#transparent} is ```true``` and this is ````false````, then the canvas clear color will
* be taken from {@link Canvas#backgroundColor}.
*
* Default value is ````true````.
*
* @type {Boolean}
*/
get backgroundColorFromAmbientLight() {
return this._backgroundColorFromAmbientLight;
}
/**
* Sets if the canvas background color is derived from an {@link AmbientLight}.
*
* This only has effect when the canvas is not transparent. When not enabled, the background color
* will be the canvas element's HTML/CSS background color.
*
* Default value is ````true````.
*
* @type {Boolean}
*/
set backgroundColorFromAmbientLight(backgroundColorFromAmbientLight) {
this._backgroundColorFromAmbientLight = (backgroundColorFromAmbientLight !== false);
this.glRedraw();
}
/**
* Gets the canvas clear color.
*
* Default value is ````[1, 1, 1]````.
*
* @type {Number[]}
*/
get backgroundColor() {
return this._backgroundColor;
}
/**
* Sets the canvas clear color.
*
* Default value is ````[1, 1, 1]````.
*
* @type {Number[]}
*/
set backgroundColor(value) {
if (value) {
this._backgroundColor[0] = value[0];
this._backgroundColor[1] = value[1];
this._backgroundColor[2] = value[2];
} else {
this._backgroundColor[0] = 1.0;
this._backgroundColor[1] = 1.0;
this._backgroundColor[2] = 1.0;
}
this.glRedraw();
}
/**
* Gets the scale of the canvas back buffer relative to the CSS-defined size of the canvas.
*
* This is a common way to trade off rendering quality for speed. If the canvas size is defined in CSS, then
* setting this to a value between ````[0..1]```` (eg ````0.5````) will render into a smaller back buffer, giving
* a performance boost.
*
* @returns {*|number} The resolution scale.
*/
get resolutionScale() {
return this._resolutionScale;
}
/**
* Sets the scale of the canvas back buffer relative to the CSS-defined size of the canvas.
*
* This is a common way to trade off rendering quality for speed. If the canvas size is defined in CSS, then
* setting this to a value between ````[0..1]```` (eg ````0.5````) will render into a smaller back buffer, giving
* a performance boost.
*
* @param {*|number} resolutionScale The resolution scale.
*/
set resolutionScale(resolutionScale) {
resolutionScale = resolutionScale || 1.0;
if (resolutionScale === this._resolutionScale) {
return;
}
this._resolutionScale = resolutionScale;
const canvas = this.canvas;
canvas.width = Math.round(canvas.clientWidth * this._resolutionScale);
canvas.height = Math.round(canvas.clientHeight * this._resolutionScale);
this.glRedraw();
}
/**
* The busy {@link Spinner} for this Canvas.
*
* @property spinner
* @type Spinner
* @final
*/
get spinner() {
return this._spinner;
}
/**
* Creates a default canvas in the DOM.
* @private
*/
_createCanvas() {
const canvasId = "xeokit-canvas-" + math.createUUID();
const body = document.getElementsByTagName("body")[0];
const div = document.createElement('div');
const style = div.style;
style.height = "100%";
style.width = "100%";
style.padding = "0";
style.margin = "0";
style.background = "rgba(0,0,0,0);";
style.float = "left";
style.left = "0";
style.top = "0";
style.position = "absolute";
style.opacity = "1.0";
style["z-index"] = "-10000";
div.innerHTML += '<canvas id="' + canvasId + '" style="width: 100%; height: 100%; float: left; margin: 0; padding: 0;"></canvas>';
body.appendChild(div);
this.canvas = document.getElementById(canvasId);
}
_getElementXY(e) {
let x = 0, y = 0;
while (e) {
x += (e.offsetLeft - e.scrollLeft);
y += (e.offsetTop - e.scrollTop);
e = e.offsetParent;
}
return {x: x, y: y};
}
/**
* Initialises the WebGL context
* @private
*/
_initWebGL() {
// Default context attribute values
if (!this.gl) {
for (let i = 0; !this.gl && i < WEBGL_CONTEXT_NAMES.length; i++) {
try {
this.gl = this.canvas.getContext(WEBGL_CONTEXT_NAMES[i], this.contextAttr);
} catch (e) { // Try with next context name
}
}
}
if (!this.gl) {
this.error('Failed to get a WebGL context');
/**
* Fired whenever the canvas failed to get a WebGL context, which probably means that WebGL
* is either unsupported or has been disabled.
* @event webglContextFailed
*/
this.fire("webglContextFailed", true, true);
}
// data-textures: avoid to re-bind same texture
{
const gl = this.gl;
let lastTextureUnit = "__";
let originalActiveTexture = gl.activeTexture;
gl.activeTexture = function (arg1) {
if (lastTextureUnit === arg1) {
return;
}
lastTextureUnit = arg1;
originalActiveTexture.call (this, arg1);
};
let lastBindTexture = {};
let originalBindTexture = gl.bindTexture;
let avoidedRebinds = 0;
gl.bindTexture = function (arg1, arg2) {
if (lastBindTexture[lastTextureUnit] === arg2)
{
avoidedRebinds++;
return;
}
lastBindTexture[lastTextureUnit] = arg2;
originalBindTexture.call (this, arg1, arg2);
}
// setInterval (
// () => {
// console.log (`${avoidedRebinds} avoided texture binds/sec`);
// avoidedRebinds = 0;
// },
// 1000
// );
}
if (this.gl) {
// Setup extension (if necessary) and hints for fragment shader derivative functions
if (this.webgl2) {
this.gl.hint(this.gl.FRAGMENT_SHADER_DERIVATIVE_HINT, this.gl.FASTEST);
// data-textures: not using standard-derivatives
if (!(this.gl instanceof WebGL2RenderingContext)) {
}
}
}
}
/**
* @private
* @deprecated
*/
getSnapshot(params) {
throw "Canvas#getSnapshot() has been replaced by Viewer#getSnapshot() - use that method instead.";
}
/**
* Reads colors of pixels from the last rendered frame.
*
* Call this method like this:
*
* ````JavaScript
*
* // Ignore transparent pixels (default is false)
* var opaqueOnly = true;
*
* var colors = new Float32Array(8);
*
* viewer.scene.canvas.readPixels([ 100, 22, 12, 33 ], colors, 2, opaqueOnly);
* ````
*
* Then the r,g,b components of the colors will be set to the colors at those pixels.
*
* @param {Number[]} pixels
* @param {Number[]} colors
* @param {Number} size
* @param {Boolean} opaqueOnly
*/
readPixels(pixels, colors, size, opaqueOnly) {
return this.scene._renderer.readPixels(pixels, colors, size, opaqueOnly);
}
/**
* Simulates lost WebGL context.
*/
loseWebGLContext() {
if (this.canvas.loseContext) {
this.canvas.loseContext();
}
}
destroy() {
this.scene.off(this._tick);
this._spinner._destroy();
// Memory leak avoidance
this.canvas.removeEventListener("webglcontextlost", this._webglcontextlostListener);
this.canvas.removeEventListener("webglcontextrestored", this._webglcontextrestoredListener);
this.gl = null;
super.destroy();
}
}
export {Canvas};
