我正在尝试将这个简单的 html 页面 add.html 转置到 vue.js：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
</head>
<body>
<input type="button" value="Add" onclick="callAdd()" />
<script>
function callAdd() {
const result = Module.ccall('Add',
'number',
['number', 'number'],
[1, 2]);
console.log(`Result: ${result}`);
}
</script>
<script src="js_plumbing.js"></script>
</body>
</html>
它调用 add.c 中定义的 Add 函数：
#include <stdlib.h>
#include <emscripten.h>
// If this is an Emscripten (WebAssembly) build then...
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#endif
#ifdef __cplusplus
extern "C" { // So that the C++ compiler does not rename our function names
#endif
EMSCRIPTEN_KEEPALIVE
int Add(int value1, int value2)
{
return (value1 + value2);
}
#ifdef __cplusplus
}
#endif
并通过命令转换为js_plumbing和js_plumbling.wasm文件：
emcc add.c -o js_plumbing.js -s EXTRA_EXPORTED_RUNTIME_METHODS=['ccall','cwrap'] -s
ENVIRONMENT='web','worker'
在谷歌浏览器的控制台中我收到以下错误：
GET http://localhost:8080/dist/js_plumbing.wasm 404 (Not Found) @ js_plumbing.js?2b2c:1653
js_plumbing_js 中的位置：
// Prefer streaming instantiation if available.
function instantiateAsync() {
if (!wasmBinary &&
typeof WebAssembly.instantiateStreaming === 'function' &&
!isDataURI(wasmBinaryFile) &&
typeof fetch === 'function') {
fetch(wasmBinaryFile, { credentials: 'same-origin' }).then(function (response) { // <---------------!!!
var result = WebAssembly.instantiateStreaming(response, info);
return result.then(receiveInstantiatedSource, function(reason) {
// We expect the most common failure cause to be a bad MIME type for the binary,
// in which case falling back to ArrayBuffer instantiation should work.
err('wasm streaming compile failed: ' + reason);
err('falling back to ArrayBuffer instantiation');
instantiateArrayBuffer(receiveInstantiatedSource);
});
});
} else {
return instantiateArrayBuffer(receiveInstantiatedSource);
}
}
在 Google Chrome 中：createWasm @ js_plumbing.js?2b2c:1680
js_plumbing.js 第 1680 行：
instantiateAsync();
在 Google Chrome 中： eval @ js_plumbing.js?2b2c:1930
js_plumbing.js 第 1930 行：
<pre><font color="#4E9A06">var</font> asm = createWasm();</pre>
还有许多与 wasm 相关的其他错误：
那么...我应该如何修改 Result.vue 中的 callAdd() 方法才能正确执行 js_plumbing.js 和 js_plumbing.wasm 文件中的 Add 函数？
methods: {
callAdd() {
const result = Module.ccall('Add',
'number',
['number', 'number'],
[1, 2]);
console.log('Result: ${result}');
}
}
Updates:
1 次更新）
我用以下命令编译了 add.c：
emcc add.c -o js_plumbing.mjs -s EXTRA_EXPORTED_RUNTIME_METHODS=
['ccall','cwrap'] -s ENVIRONMENT='web' .
然后创建一个 js_plumbing.js 文件：
. import wasm from './js_plumbing.mjs';
const instance = wasm({
onRuntimeInitialized() {
console.log(instance._addTwoNumbers(3,2));
}
}) .
执行 npm run dev：
Failed to compile.
./src/components/js_plumbing.mjs 3:25
Module parse failed: Unexpected token (3:25)
You may need an appropriate loader to handle this file type, currently
no loaders are configured to process this file.
See https://webpack.js.org/concepts#loaders
|
| var Module = (function() {
> var _scriptDir = import.meta.url;
|
| return (
更新2)
我通过将 wasm 文件放入 index.html 文件同一文件夹内的 /div 子文件夹中解决了 404 错误。
Now I’m facing this problem: “Cannot read property ‘ccall’ of undefined”
但我使用此命令编译了 add.c 文件，创建了 js_plumbing.js 和 js_plumbing.wasm 文件，该命令导出了方法 ‘ccall’ 和 ‘cwrap’ ：
emcc add.c -o js_plumbing.js -s EXTRA_EXPORTED_RUNTIME_METHODS=[‘ccall’,‘cwrap’] -s ENVIRONMENT=‘web’,‘worker’
3°更新）
我通过某种黑客手段“解决”了这个问题，但我根本不喜欢这种方式。
这是 Result.vue 文件：
<template>
<div>
<p button @click="callAdd">Add!</p>
<p>Result: {{ result }}</p>
</div>
</template>
<script>
import * as js_plumbing from './js_plumbing'
import Module from './js_plumbing'
export default {
data () {
return {
result: null
}
},
methods: {
callAdd () {
const result = js_plumbing.Module.ccall('Add',
'number',
['number', 'number'],
[1, 2]);
this.result = result;
}
}
}
</script>
和之前用的一模一样
为了使其正常工作，我所做的唯一一件事是将导出添加到 js_plumbing.js 中的模块定义中：
js_plumbing.js
// Copyright 2010 The Emscripten Authors. All rights reserved.
// Emscripten is available under two separate licenses, the MIT
license and the
// University of Illinois/NCSA Open Source License. Both these
licenses can be
// found in the LICENSE file.
// The Module object: Our interface to the outside world. We import
// and export values on it. There are various ways Module can be used:
// 1. Not defined. We create it here
// 2. A function parameter, function(Module) { ..generated code.. }
// 3. pre-run appended it, var Module = {}; ..generated code..
// 4. External script tag defines var Module.
// We need to check if Module already exists (e.g. case 3 above).
// Substitution will be replaced with actual code on later stage of
the build,
// this way Closure Compiler will not mangle it (e.g. case 4. above).
// Note that if you want to run closure, and also to use Module
// after the generated code, you will need to define var Module =
{};
// before the code. Then that object will be used in the code, and you
// can continue to use Module afterwards as well.
export var Module = typeof Module !== 'undefined' ? Module : {};
但是，正如我所说，我不喜欢这种黑客行为。 关于如何使模块可导出、从而可导入，而不需要在 js_plumbing.js 文件中手动添加“导出”，有什么建议吗？
首先，应该解决 404 错误。是否归档/dist/js_plumbing.wasm存在？我过去需要手动复制 .wasm 文件，因为某些自动构建系统（如 Parcel）目前不需要。
您可以使用MODULARIZE导入到构建系统的选项。
addTwoNumbers.c
#include <emscripten.h>
EMSCRIPTEN_KEEPALIVE
int addTwoNumbers(int value1, int value2)
{
return (value1 + value2);
}
构建命令
$ emcc -o dist/addTwoNumbers.js -s MODULARIZE=1 src/addTwoNumbers.c
Vue 实现
import myMathModule from './js_plumbing';
let instance = {
ready: new Promise(resolve => {
myMathModule({
onRuntimeInitialized() {
instance = Object.assign(this, {
ready: Promise.resolve()
});
resolve();
}
});
})
};
export default {
data () {
return {
result: null
};
},
methods: {
callAdd(a, b) {
instance.ready
.then(_ => this.result = instance._add(a, b));
}
}
};
Use the onRuntimeInitialized检测 WASM 模块何时准备就绪的方法。您导出的函数前面会有一个下划线。
require()可能可以用来代替import:
const wasmModule = require('./addTwoNumbers.js');
...