blob: 179b64b3dd3bbe0c64bdffd60cf168ed35c81105 [file] [log] [blame]
// Adds compile-time JS functions to augment the CanvasKit interface.
// Specifically, anything that should only be on the GPU version of canvaskit.
(function(CanvasKit){
CanvasKit._extraInitializations = CanvasKit._extraInitializations || [];
CanvasKit._extraInitializations.push(function() {
function get(obj, attr, defaultValue) {
if (obj && obj.hasOwnProperty(attr)) {
return obj[attr];
}
return defaultValue;
}
function makeWebGLContext(canvas, attrs) {
// These defaults come from the emscripten _emscripten_webgl_create_context
var contextAttributes = {
alpha: get(attrs, 'alpha', 1),
depth: get(attrs, 'depth', 1),
stencil: get(attrs, 'stencil', 0),
antialias: get(attrs, 'antialias', 1),
premultipliedAlpha: get(attrs, 'premultipliedAlpha', 1),
preserveDrawingBuffer: get(attrs, 'preserveDrawingBuffer', 0),
preferLowPowerToHighPerformance: get(attrs, 'preferLowPowerToHighPerformance', 0),
failIfMajorPerformanceCaveat: get(attrs, 'failIfMajorPerformanceCaveat', 0),
majorVersion: get(attrs, 'majorVersion', 2),
minorVersion: get(attrs, 'minorVersion', 0),
enableExtensionsByDefault: get(attrs, 'enableExtensionsByDefault', 1),
explicitSwapControl: get(attrs, 'explicitSwapControl', 0),
renderViaOffscreenBackBuffer: get(attrs, 'renderViaOffscreenBackBuffer', 0),
};
if (!canvas) {
SkDebug('null canvas passed into makeWebGLContext');
return 0;
}
// This check is from the emscripten version
if (contextAttributes['explicitSwapControl']) {
SkDebug('explicitSwapControl is not supported');
return 0;
}
// GL is an enscripten provided helper
// See https://github.com/emscripten-core/emscripten/blob/incoming/src/library_webgl.js
var ctx = GL.createContext(canvas, contextAttributes);
if (!ctx && contextAttributes.majorVersion > 1) {
contextAttributes.majorVersion = 1; // fall back to WebGL 1.0
contextAttributes.minorVersion = 0;
ctx = GL.createContext(canvas, contextAttributes);
}
return ctx;
}
CanvasKit.GetWebGLContext = function(canvas, attrs) {
return makeWebGLContext(canvas, attrs);
};
// arg can be of types:
// - String - in which case it is interpreted as an id of a
// canvas element.
// - HTMLCanvasElement - in which the provided canvas element will
// be used directly.
// Width and height can be provided to override those on the canvas
// element, or specify a height for when a context is provided.
CanvasKit.MakeWebGLCanvasSurface = function(arg, width, height) {
var canvas = arg;
if (canvas.tagName !== 'CANVAS') {
canvas = document.getElementById(arg);
if (!canvas) {
throw 'Canvas with id ' + arg + ' was not found';
}
}
// we are ok with all the defaults
var ctx = this.GetWebGLContext(canvas);
if (!ctx || ctx < 0) {
throw 'failed to create webgl context: err ' + ctx;
}
if (!canvas && (!width || !height)) {
throw 'height and width must be provided with context';
}
var grcontext = this.MakeGrContext(ctx);
// Bump the default resource cache limit.
var RESOURCE_CACHE_BYTES = 256 * 1024 * 1024;
grcontext.setResourceCacheLimitBytes(RESOURCE_CACHE_BYTES);
// Maybe better to use clientWidth/height. See:
// https://webglfundamentals.org/webgl/lessons/webgl-anti-patterns.html
var surface = this.MakeOnScreenGLSurface(grcontext,
width || canvas.width,
height || canvas.height);
if (!surface) {
SkDebug('falling back from GPU implementation to a SW based one');
// we need to throw away the old canvas (which was locked to
// a webGL context) and create a new one so we can
var newCanvas = canvas.cloneNode(true);
var parent = canvas.parentNode;
parent.replaceChild(newCanvas, canvas);
// add a class so the user can detect that it was replaced.
newCanvas.classList.add('ck-replaced');
return CanvasKit.MakeSWCanvasSurface(newCanvas);
}
surface._context = ctx;
surface.grContext = grcontext;
return surface;
};
// Default to trying WebGL first.
CanvasKit.MakeCanvasSurface = CanvasKit.MakeWebGLCanvasSurface;
});
}(Module)); // When this file is loaded in, the high level object is "Module";