在 Web Worker（Emscripten 和 Rust）中创建 SDL Canvas 时出现问题 - 错误：GLctx 未定义

Question

我在 Web Worker 中创建 SDL 画布时遇到问题。

该程序作为库启动，并且在 Emscripten 构建中没有名为 main() 的函数：

// Run as Library (e.g. Android and WebAssembly)
#[no_mangle]
#[allow(non_snake_case)]
pub extern fn SDL_main(_argc: libc::c_int, _argv: *const *const libc::c_char) -> libc::c_int {
    game::start();
    return 0;
}

触发问题的代码行（在 Rust 中从主线程启动的渲染线程中）：

    // ...

    let window: Window = video_subsystem.window("Alexis' Game Engine", 800, 600)
                                        .position_centered()
                                        .resizable()
                                        .build()
                                        .expect("Could Not Make a Window");
    debug!("Window Created...");

    // The below line of code is what triggers the issue
    let mut canvas: Canvas<Window> = window.into_canvas()
                                            .accelerated()
                                            .present_vsync()
                                            .build()
                                            .expect("Could Not Make a Canvas");
    debug!("Canvas Created...");

    // ...

下面的代码是从主线程启动渲染线程的代码

    // ...

    #[cfg(feature="client")]
    let render_thread: JoinHandle<()> = thread::Builder::new().name("render".to_string())
                    .spawn(|| render::start(rrtx, srrx)).unwrap();  // Client

    // ...

根据链接文档，

OFFSCREEN_FRAMEBUFFER和OFFSCREENCANVAS_SUPPORT都应该有助于解决此问题

    // These are the flags that are used to build the webassembly files. This includes main.js, main.wasm, main.worker.js, and main.ww.js. main.ww.js is unused.
    println!("cargo:rustc-env=EMCC_CFLAGS=-O3 -pthread -s STRICT_JS=1 \
                -s WASM=1 \
                -s WASM_BIGINT=1 \
                -s SUPPORT_BIG_ENDIAN=1 \
                -s ALLOW_MEMORY_GROWTH=1 \
                -s SHARED_MEMORY=1 \
                -s ABORT_ON_WASM_EXCEPTIONS=0 \
                -s WASM_WORKERS=1 \
                -s WASMFS=1 \
                -s MINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION=1 \
                -s TRUSTED_TYPES=1 \
                -s ASSERTIONS=1 \
                -s PTHREADS_DEBUG=0 \
                -s RUNTIME_DEBUG=0 \
                -s ALLOW_BLOCKING_ON_MAIN_THREAD=0 \
                -s PTHREAD_POOL_SIZE=3 \
                -s OFFSCREEN_FRAMEBUFFER=1 \
                -s OFFSCREENCANVAS_SUPPORT=1 \
                -lSDL2 \
                -lSDL2_image \
                -lSDL2_ttf \
                -s EXPORTED_FUNCTIONS=\"['_SDL_main', '_malloc']\"
            ");

下面的 Firefox 屏幕截图显示了错误

TypeError: GLctx is undefined

下面的 Chrome 屏幕截图显示了错误

(index):49 TypeError: Cannot read properties of undefined (reading 'createShader')

Answer 1

你的问题解决了吗？我有一模一样的 附：我没有资格写评论；|