virtualx-engine/platform/javascript/engine.js
Zaven Muradyan 61d5513525 Add comments to javascript wrapper parts.
The code in pre.js and engine.js is a bit confusing to see in isolation,
since the files aren't valid JS files by themselves. This just adds some
explanatory text to both files.

Fixes #22937.
2018-10-15 08:56:44 -07:00

415 lines
10 KiB
JavaScript

// The following is concatenated with generated code, and acts as the end
// of a wrapper for said code. See pre.js for the other part of the
// wrapper.
exposedLibs['PATH'] = PATH;
exposedLibs['FS'] = FS;
return Module;
},
};
(function() {
var engine = Engine;
var DOWNLOAD_ATTEMPTS_MAX = 4;
var basePath = null;
var wasmFilenameExtensionOverride = null;
var engineLoadPromise = null;
var loadingFiles = {};
function getPathLeaf(path) {
while (path.endsWith('/'))
path = path.slice(0, -1);
return path.slice(path.lastIndexOf('/') + 1);
}
function getBasePath(path) {
if (path.endsWith('/'))
path = path.slice(0, -1);
if (path.lastIndexOf('.') > path.lastIndexOf('/'))
path = path.slice(0, path.lastIndexOf('.'));
return path;
}
function getBaseName(path) {
return getPathLeaf(getBasePath(path));
}
Engine = function Engine() {
this.rtenv = null;
var LIBS = {};
var initPromise = null;
var unloadAfterInit = true;
var preloadedFiles = [];
var resizeCanvasOnStart = true;
var progressFunc = null;
var preloadProgressTracker = {};
var lastProgress = { loaded: 0, total: 0 };
var canvas = null;
var executableName = null;
var locale = null;
var stdout = null;
var stderr = null;
this.init = function(newBasePath) {
if (!initPromise) {
initPromise = Engine.load(newBasePath).then(
instantiate.bind(this)
);
requestAnimationFrame(animateProgress);
if (unloadAfterInit)
initPromise.then(Engine.unloadEngine);
}
return initPromise;
};
function instantiate(wasmBuf) {
var rtenvProps = {
engine: this,
ENV: {},
};
if (typeof stdout === 'function')
rtenvProps.print = stdout;
if (typeof stderr === 'function')
rtenvProps.printErr = stderr;
rtenvProps.instantiateWasm = function(imports, onSuccess) {
WebAssembly.instantiate(wasmBuf, imports).then(function(result) {
onSuccess(result.instance);
});
return {};
};
return new Promise(function(resolve, reject) {
rtenvProps.onRuntimeInitialized = resolve;
rtenvProps.onAbort = reject;
rtenvProps.engine.rtenv = Engine.RuntimeEnvironment(rtenvProps, LIBS);
});
}
this.preloadFile = function(pathOrBuffer, destPath) {
if (pathOrBuffer instanceof ArrayBuffer) {
pathOrBuffer = new Uint8Array(pathOrBuffer);
} else if (ArrayBuffer.isView(pathOrBuffer)) {
pathOrBuffer = new Uint8Array(pathOrBuffer.buffer);
}
if (pathOrBuffer instanceof Uint8Array) {
preloadedFiles.push({
path: destPath,
buffer: pathOrBuffer
});
return Promise.resolve();
} else if (typeof pathOrBuffer === 'string') {
return loadPromise(pathOrBuffer, preloadProgressTracker).then(function(xhr) {
preloadedFiles.push({
path: destPath || pathOrBuffer,
buffer: xhr.response
});
});
} else {
throw Promise.reject("Invalid object for preloading");
}
};
this.start = function() {
return this.init().then(
Function.prototype.apply.bind(synchronousStart, this, arguments)
);
};
this.startGame = function(mainPack) {
executableName = getBaseName(mainPack);
var mainArgs = [];
if (!getPathLeaf(mainPack).endsWith('.pck')) {
mainArgs = ['--main-pack', getPathLeaf(mainPack)];
}
return Promise.all([
// Load from directory,
this.init(getBasePath(mainPack)),
// ...but write to root where the engine expects it.
this.preloadFile(mainPack, getPathLeaf(mainPack))
]).then(
Function.prototype.apply.bind(synchronousStart, this, mainArgs)
);
};
function synchronousStart() {
if (canvas instanceof HTMLCanvasElement) {
this.rtenv.canvas = canvas;
} else {
var firstCanvas = document.getElementsByTagName('canvas')[0];
if (firstCanvas instanceof HTMLCanvasElement) {
this.rtenv.canvas = firstCanvas;
} else {
throw new Error("No canvas found");
}
}
var actualCanvas = this.rtenv.canvas;
// canvas can grab focus on click
if (actualCanvas.tabIndex < 0) {
actualCanvas.tabIndex = 0;
}
// necessary to calculate cursor coordinates correctly
actualCanvas.style.padding = 0;
actualCanvas.style.borderWidth = 0;
actualCanvas.style.borderStyle = 'none';
// disable right-click context menu
actualCanvas.addEventListener('contextmenu', function(ev) {
ev.preventDefault();
}, false);
// until context restoration is implemented
actualCanvas.addEventListener('webglcontextlost', function(ev) {
alert("WebGL context lost, please reload the page");
ev.preventDefault();
}, false);
if (locale) {
this.rtenv.locale = locale;
} else {
this.rtenv.locale = navigator.languages ? navigator.languages[0] : navigator.language;
}
this.rtenv.locale = this.rtenv.locale.split('.')[0];
this.rtenv.resizeCanvasOnStart = resizeCanvasOnStart;
this.rtenv.thisProgram = executableName || getBaseName(basePath);
preloadedFiles.forEach(function(file) {
var dir = LIBS.PATH.dirname(file.path);
try {
LIBS.FS.stat(dir);
} catch (e) {
if (e.code !== 'ENOENT') {
throw e;
}
LIBS.FS.mkdirTree(dir);
}
LIBS.FS.createDataFile('/', file.path, new Uint8Array(file.buffer), true, true, true);
}, this);
preloadedFiles = null;
initPromise = null;
this.rtenv.callMain(arguments);
}
this.setProgressFunc = function(func) {
progressFunc = func;
};
this.setResizeCanvasOnStart = function(enabled) {
resizeCanvasOnStart = enabled;
};
function animateProgress() {
var loaded = 0;
var total = 0;
var totalIsValid = true;
var progressIsFinal = true;
[loadingFiles, preloadProgressTracker].forEach(function(tracker) {
Object.keys(tracker).forEach(function(file) {
if (!tracker[file].final)
progressIsFinal = false;
if (!totalIsValid || tracker[file].total === 0) {
totalIsValid = false;
total = 0;
} else {
total += tracker[file].total;
}
loaded += tracker[file].loaded;
});
});
if (loaded !== lastProgress.loaded || total !== lastProgress.total) {
lastProgress.loaded = loaded;
lastProgress.total = total;
if (typeof progressFunc === 'function')
progressFunc(loaded, total);
}
if (!progressIsFinal)
requestAnimationFrame(animateProgress);
}
this.setCanvas = function(elem) {
canvas = elem;
};
this.setExecutableName = function(newName) {
executableName = newName;
};
this.setLocale = function(newLocale) {
locale = newLocale;
};
this.setUnloadAfterInit = function(enabled) {
if (enabled && !unloadAfterInit && initPromise) {
initPromise.then(Engine.unloadEngine);
}
unloadAfterInit = enabled;
};
this.setStdoutFunc = function(func) {
var print = function(text) {
if (arguments.length > 1) {
text = Array.prototype.slice.call(arguments).join(" ");
}
func(text);
};
if (this.rtenv)
this.rtenv.print = print;
stdout = print;
};
this.setStderrFunc = function(func) {
var printErr = function(text) {
if (arguments.length > 1)
text = Array.prototype.slice.call(arguments).join(" ");
func(text);
};
if (this.rtenv)
this.rtenv.printErr = printErr;
stderr = printErr;
};
}; // Engine()
Engine.RuntimeEnvironment = engine.RuntimeEnvironment;
Engine.isWebGLAvailable = function(majorVersion = 1) {
var testContext = false;
try {
var testCanvas = document.createElement('canvas');
if (majorVersion === 1) {
testContext = testCanvas.getContext('webgl') || testCanvas.getContext('experimental-webgl');
} else if (majorVersion === 2) {
testContext = testCanvas.getContext('webgl2') || testCanvas.getContext('experimental-webgl2');
}
} catch (e) {}
return !!testContext;
};
Engine.setWebAssemblyFilenameExtension = function(override) {
if (String(override).length === 0) {
throw new Error('Invalid WebAssembly filename extension override');
}
wasmFilenameExtensionOverride = String(override);
}
Engine.load = function(newBasePath) {
if (newBasePath !== undefined) basePath = getBasePath(newBasePath);
if (engineLoadPromise === null) {
if (typeof WebAssembly !== 'object')
return Promise.reject(new Error("Browser doesn't support WebAssembly"));
// TODO cache/retrieve module to/from idb
engineLoadPromise = loadPromise(basePath + '.' + (wasmFilenameExtensionOverride || 'wasm')).then(function(xhr) {
return xhr.response;
});
engineLoadPromise = engineLoadPromise.catch(function(err) {
engineLoadPromise = null;
throw err;
});
}
return engineLoadPromise;
};
Engine.unload = function() {
engineLoadPromise = null;
};
function loadPromise(file, tracker) {
if (tracker === undefined)
tracker = loadingFiles;
return new Promise(function(resolve, reject) {
loadXHR(resolve, reject, file, tracker);
});
}
function loadXHR(resolve, reject, file, tracker) {
var xhr = new XMLHttpRequest;
xhr.open('GET', file);
if (!file.endsWith('.js')) {
xhr.responseType = 'arraybuffer';
}
['loadstart', 'progress', 'load', 'error', 'abort'].forEach(function(ev) {
xhr.addEventListener(ev, onXHREvent.bind(xhr, resolve, reject, file, tracker));
});
xhr.send();
}
function onXHREvent(resolve, reject, file, tracker, ev) {
if (this.status >= 400) {
if (this.status < 500 || ++tracker[file].attempts >= DOWNLOAD_ATTEMPTS_MAX) {
reject(new Error("Failed loading file '" + file + "': " + this.statusText));
this.abort();
return;
} else {
setTimeout(loadXHR.bind(null, resolve, reject, file, tracker), 1000);
}
}
switch (ev.type) {
case 'loadstart':
if (tracker[file] === undefined) {
tracker[file] = {
total: ev.total,
loaded: ev.loaded,
attempts: 0,
final: false,
};
}
break;
case 'progress':
tracker[file].loaded = ev.loaded;
tracker[file].total = ev.total;
break;
case 'load':
tracker[file].final = true;
resolve(this);
break;
case 'error':
if (++tracker[file].attempts >= DOWNLOAD_ATTEMPTS_MAX) {
tracker[file].final = true;
reject(new Error("Failed loading file '" + file + "'"));
} else {
setTimeout(loadXHR.bind(null, resolve, reject, file, tracker), 1000);
}
break;
case 'abort':
tracker[file].final = true;
reject(new Error("Loading file '" + file + "' was aborted."));
break;
}
}
})();