Support for --target wasm32-unknown-emscripten

gfx-rs · Dec 3, 2021 · e86e194 · e86e194
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commit e86e194
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diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -77,6 +77,13 @@ jobs:
             target: wasm32-unknown-unknown
             kind: webgl
 
+          # Emscripten WebGL
+          - name: WebAssembly emscripten
+            os: ubuntu-20.04
+            channel: stable
+            target: wasm32-unknown-emscripten
+            kind: compile
+
     name: Check ${{ matrix.name }}
     runs-on: ${{ matrix.os }}
 

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -24,7 +24,7 @@ default-members = ["wgpu", "wgpu-hal", "wgpu-info"]
 [patch."https://github.com/zakarumych/gpu-alloc"]
 #gpu-alloc = { path = "../gpu-alloc/gpu-alloc" }
 
-[patch."https://github.com/grovesNL/glow"]
+[patch."https://github.com/caiiiycuk/glow"]
 #glow = { path = "../glow" }
 
 [patch.crates-io]

diff --git a/run-wasm-emscripten-example.sh b/run-wasm-emscripten-example.sh
@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+
+set -e
+
+set -- hello-triangle
+echo "Compiling..."
+EMMAKEN_CFLAGS="-g -s ERROR_ON_UNDEFINED_SYMBOLS=0 --no-entry -s FULL_ES3=1" cargo build --example $1 --target wasm32-unknown-emscripten
+
+mkdir -p target/wasm-examples/$1/
+cp target/wasm32-unknown-emscripten/debug/examples/* target/wasm-examples/$1
+cat wasm-resources/index.em.template.html | sed "s/{{example}}/$1/g" > target/wasm-examples/$1/index.html
+
+# Find a serving tool to host the example
+SERVE_CMD=""
+SERVE_ARGS=""
+if which basic-http-server; then
+    SERVE_CMD="basic-http-server"
+    SERVE_ARGS="target/wasm-examples/$1 -a 127.0.0.1:1234"
+elif which miniserve && python3 -m http.server --help > /dev/null; then
+    SERVE_CMD="miniserve"
+    SERVE_ARGS="target/wasm-examples/$1 -p 1234 --index index.html"
+elif python3 -m http.server --help > /dev/null; then
+    SERVE_CMD="python3"
+    SERVE_ARGS="-m http.server --directory target/wasm-examples/$1 1234"
+fi
+
+# Exit if we couldn't find a tool to serve the example with
+if [ "$SERVE_CMD" = "" ]; then
+    echo "Couldn't find a utility to use to serve the example web page. You can serve the `target/wasm-examples/$1` folder yourself using any simple static http file server."
+fi
+
+echo "Serving example with $SERVE_CMD at http://localhost:1234"
+$SERVE_CMD $SERVE_ARGS
diff --git a/wasm-resources/index.em.template.html b/wasm-resources/index.em.template.html
@@ -0,0 +1,15 @@
+<html>
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  </head>
+  <body>
+    <canvas id="canvas" width="640" height="400"></canvas>
+    <script>
+        var Module = {
+            canvas: document.getElementById("canvas"),
+        };
+    </script>
+    <script src="{{example}}.js"></script>
+  </body>
+</html>
diff --git a/wgpu-hal/Cargo.toml b/wgpu-hal/Cargo.toml
@@ -43,7 +43,9 @@ gpu-descriptor = { version = "0.2", optional = true }
 inplace_it = { version ="0.3.3", optional = true }
 
 # backend: Gles
-glow = { version = "0.11", optional = true }
+# TODO: remove caiiiycuk/glow when
+# https://github.com/grovesNL/glow/pull/195 will be merged
+glow = { git = "https://github.com/caiiiycuk/glow", rev = "5abe786", optional = true }
 
 # backend: Dx12
 bit-set = { version = "0.5", optional = true }
@@ -59,6 +61,10 @@ egl = { package = "khronos-egl", version = "4.1", features = ["dynamic"], option
 #Note: it's only unused on Apple platforms
 libloading = { version = "0.7", optional = true }
 
+[target.'cfg(target_os = "emscripten")'.dependencies]
+egl = { package = "khronos-egl", version = "4.1", features = ["static", "no-pkg-config"], optional = true }
+libloading = { version = "0.7", optional = true }
+
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["libloaderapi", "windef", "winuser"] }
 native = { package = "d3d12", version = "0.4.1", features = ["libloading"], optional = true }
@@ -68,7 +74,7 @@ mtl = { package = "metal", version = "0.23.1" }
 objc = "0.2.5"
 core-graphics-types = "0.1"
 
-[target.'cfg(target_arch = "wasm32")'.dependencies]
+[target.'cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))'.dependencies]
 wasm-bindgen = { version = "0.2" }
 web-sys = { version = "0.3", features = ["Window", "HtmlCanvasElement", "WebGl2RenderingContext"] }
 js-sys = { version = "0.3" }
@@ -86,4 +92,6 @@ features = ["wgsl-in"]
 
 [dev-dependencies]
 env_logger = "0.8"
+
+[target.'cfg(not(target_os = "emscripten"))'.dev-dependencies]
 winit = "0.26"
diff --git a/wgpu-hal/src/gles/device.rs b/wgpu-hal/src/gles/device.rs
@@ -1096,6 +1096,8 @@ impl crate::Device<super::Api> for super::Device {
         #[cfg_attr(target_arch = "wasm32", allow(clippy::needless_borrow))]
         Ok(fence.get_latest(&self.shared.context.lock()))
     }
+
+    #[cfg_attr(target_os = "emscripten", allow(unreachable_code, unused_variables))]
     unsafe fn wait(
         &self,
         fence: &super::Fence,
@@ -1114,6 +1116,12 @@ impl crate::Device<super::Api> for super::Device {
                 .iter()
                 .find(|&&(value, _)| value >= wait_value)
                 .unwrap();
+
+            // for some reason signature of glow's client_wait_sync didn't match to emscripten's client_wait_sync
+            // however it should be noop in emscripten
+            #[cfg(target_os = "emscripten")]
+            return Ok(true);
+
             match gl.client_wait_sync(sync, glow::SYNC_FLUSH_COMMANDS_BIT, timeout_ns as i32) {
                 // for some reason firefox returns WAIT_FAILED, to investigate
                 #[cfg(target_arch = "wasm32")]

diff --git a/wgpu-hal/src/gles/egl.rs b/wgpu-hal/src/gles/egl.rs
@@ -10,7 +10,9 @@ const CONTEXT_LOCK_TIMEOUT_SECS: u64 = 1;
 const EGL_CONTEXT_FLAGS_KHR: i32 = 0x30FC;
 const EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR: i32 = 0x0001;
 const EGL_CONTEXT_OPENGL_ROBUST_ACCESS_EXT: i32 = 0x30BF;
+#[cfg_attr(target_os = "emscripten", allow(dead_code))]
 const EGL_PLATFORM_WAYLAND_KHR: u32 = 0x31D8;
+#[cfg_attr(target_os = "emscripten", allow(dead_code))]
 const EGL_PLATFORM_X11_KHR: u32 = 0x31D5;
 const EGL_GL_COLORSPACE_KHR: u32 = 0x309D;
 const EGL_GL_COLORSPACE_SRGB_KHR: u32 = 0x3089;
@@ -23,12 +25,20 @@ type WlDisplayConnectFun =
 
 type WlDisplayDisconnectFun = unsafe extern "system" fn(display: *const raw::c_void);
 
+#[cfg(not(target_os = "emscripten"))]
+type EglInstance = egl::DynamicInstance<egl::EGL1_4>;
+
+#[cfg(target_os = "emscripten")]
+type EglInstance = egl::Instance<egl::Static>;
+
+#[cfg_attr(target_os = "emscripten", allow(dead_code))]
 type WlEglWindowCreateFun = unsafe extern "system" fn(
     surface: *const raw::c_void,
     width: raw::c_int,
     height: raw::c_int,
 ) -> *mut raw::c_void;
 
+#[cfg_attr(target_os = "emscripten", allow(dead_code))]
 type WlEglWindowResizeFun = unsafe extern "system" fn(
     window: *const raw::c_void,
     width: raw::c_int,
@@ -141,7 +151,7 @@ enum SrgbFrameBufferKind {
 
 /// Choose GLES framebuffer configuration.
 fn choose_config(
-    egl: &egl::DynamicInstance<egl::EGL1_4>,
+    egl: &EglInstance,
     display: egl::Display,
     srgb_kind: SrgbFrameBufferKind,
 ) -> Result<(egl::Config, bool), crate::InstanceError> {
@@ -249,7 +259,7 @@ fn gl_debug_message_callback(source: u32, gltype: u32, id: u32, severity: u32, m
 /// exclusive access when shared with multiple threads.
 pub struct AdapterContext {
     glow_context: Mutex<glow::Context>,
-    egl: Arc<egl::DynamicInstance<egl::EGL1_4>>,
+    egl: Arc<EglInstance>,
     egl_display: egl::Display,
     pub(super) egl_context: egl::Context,
     egl_pbuffer: Option<egl::Surface>,
@@ -261,7 +271,7 @@ unsafe impl Send for AdapterContext {}
 /// A guard containing a lock to an [`AdapterContext`]
 pub struct AdapterContextLock<'a> {
     glow_context: MutexGuard<'a, glow::Context>,
-    egl: &'a Arc<egl::DynamicInstance<egl::EGL1_4>>,
+    egl: &'a Arc<EglInstance>,
     egl_display: egl::Display,
 }
 
@@ -331,7 +341,7 @@ impl AdapterContext {
 
 #[derive(Debug)]
 struct Inner {
-    egl: Arc<egl::DynamicInstance<egl::EGL1_4>>,
+    egl: Arc<EglInstance>,
     #[allow(unused)]
     version: (i32, i32),
     supports_native_window: bool,
@@ -341,6 +351,7 @@ struct Inner {
     /// Dummy pbuffer (1x1).
     /// Required for `eglMakeCurrent` on platforms that doesn't supports `EGL_KHR_surfaceless_context`.
     pbuffer: Option<egl::Surface>,
+    #[cfg_attr(target_os = "emscripten", allow(dead_code))]
     wl_display: Option<*mut raw::c_void>,
     /// Method by which the framebuffer should support srgb
     srgb_kind: SrgbFrameBufferKind,
@@ -349,7 +360,7 @@ struct Inner {
 impl Inner {
     fn create(
         flags: crate::InstanceFlags,
-        egl: Arc<egl::DynamicInstance<egl::EGL1_4>>,
+        egl: Arc<EglInstance>,
         display: egl::Display,
     ) -> Result<Self, crate::InstanceError> {
         let version = egl.initialize(display).map_err(|_| crate::InstanceError)?;
@@ -443,8 +454,12 @@ impl Inner {
             }
         };
 
+        #[cfg(target_os = "emscripten")]
+        let pbuffer = None;
+
         // Testing if context can be binded without surface
         // and creating dummy pbuffer surface if not.
+        #[cfg(not(target_os = "emscripten"))]
         let pbuffer =
             if version >= (1, 5) || display_extensions.contains("EGL_KHR_surfaceless_context") {
                 log::info!("\tEGL context: +surfaceless");
@@ -494,7 +509,12 @@ unsafe impl Send for Instance {}
 unsafe impl Sync for Instance {}
 
 impl crate::Instance<super::Api> for Instance {
+    #[cfg_attr(target_os = "emscripten", allow(unused_variables, unused_mut))]
     unsafe fn init(desc: &crate::InstanceDescriptor) -> Result<Self, crate::InstanceError> {
+        #[cfg(target_os = "emscripten")]
+        let egl = Arc::new(egl::Instance::new(egl::Static));
+
+        #[cfg(not(target_os = "emscripten"))]
         let egl = match egl::DynamicInstance::<egl::EGL1_4>::load_required() {
             Ok(egl) => Arc::new(egl),
             Err(e) => {
@@ -528,6 +548,7 @@ impl crate::Instance<super::Api> for Instance {
             None
         };
 
+        #[cfg(not(target_os = "emscripten"))]
         let display = if let (Some(library), Some(egl)) =
             (wayland_library, egl.upcast::<egl::EGL1_5>())
         {
@@ -553,6 +574,9 @@ impl crate::Instance<super::Api> for Instance {
             egl.get_display(egl::DEFAULT_DISPLAY).unwrap()
         };
 
+        #[cfg(target_os = "emscripten")]
+        let display = egl.get_display(egl::DEFAULT_DISPLAY).unwrap();
+
         if desc.flags.contains(crate::InstanceFlags::VALIDATION)
             && client_ext_str.contains(&"EGL_KHR_debug")
         {
@@ -582,7 +606,10 @@ impl crate::Instance<super::Api> for Instance {
         })
     }
 
-    #[cfg_attr(target_os = "macos", allow(unused, unused_mut, unreachable_code))]
+    #[cfg_attr(
+        any(target_os = "macos", target_os = "emscripten"),
+        allow(unused, unused_mut, unreachable_code)
+    )]
     unsafe fn create_surface(
         &self,
         has_handle: &impl HasRawWindowHandle,
@@ -611,6 +638,7 @@ impl crate::Instance<super::Api> for Instance {
                     return Err(crate::InstanceError);
                 }
             }
+            #[cfg(not(target_os = "emscripten"))]
             Rwh::Wayland(handle) => {
                 /* Wayland displays are not sharable between surfaces so if the
                  * surface we receive from this handle is from a different
@@ -645,6 +673,8 @@ impl crate::Instance<super::Api> for Instance {
                     drop(old_inner);
                 }
             }
+            #[cfg(target_os = "emscripten")]
+            Rwh::Web(_) => {}
             other => {
                 log::error!("Unsupported window: {:?}", other);
                 return Err(crate::InstanceError);
@@ -736,7 +766,7 @@ pub struct Swapchain {
 
 #[derive(Debug)]
 pub struct Surface {
-    egl: Arc<egl::DynamicInstance<egl::EGL1_4>>,
+    egl: Arc<EglInstance>,
     wsi_library: Option<Arc<libloading::Library>>,
     config: egl::Config,
     display: egl::Display,
@@ -875,6 +905,8 @@ impl crate::Surface<super::Api> for Surface {
                         wl_window = Some(window);
                         window
                     }
+                    #[cfg(target_os = "emscripten")]
+                    Rwh::Web(handle) => handle.id as *mut std::ffi::c_void,
                     _ => unreachable!(),
                 };
 
@@ -900,6 +932,7 @@ impl crate::Surface<super::Api> for Surface {
                 attributes.push(egl::ATTRIB_NONE as i32);
 
                 // Careful, we can still be in 1.4 version even if `upcast` succeeds
+                #[cfg(not(target_os = "emscripten"))]
                 let raw_result = if let Some(egl) = self.egl.upcast::<egl::EGL1_5>() {
                     let attributes_usize = attributes
                         .into_iter()
@@ -920,6 +953,14 @@ impl crate::Surface<super::Api> for Surface {
                     )
                 };
 
+                #[cfg(target_os = "emscripten")]
+                let raw_result = self.egl.create_window_surface(
+                    self.display,
+                    self.config,
+                    native_window_ptr,
+                    Some(&attributes),
+                );
+
                 match raw_result {
                     Ok(raw) => (raw, wl_window),
                     Err(e) => {

diff --git a/wgpu-hal/src/gles/mod.rs b/wgpu-hal/src/gles/mod.rs
@@ -56,9 +56,9 @@ To address this, we invalidate the vertex buffers based on:
 
 */
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(any(not(target_arch = "wasm32"), target_os = "emscripten"))]
 mod egl;
-#[cfg(target_arch = "wasm32")]
+#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
 mod web;
 
 mod adapter;
@@ -67,10 +67,10 @@ mod conv;
 mod device;
 mod queue;
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(any(not(target_arch = "wasm32"), target_os = "emscripten"))]
 use self::egl::{AdapterContext, Instance, Surface};
 
-#[cfg(target_arch = "wasm32")]
+#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
 use self::web::{AdapterContext, Instance, Surface};
 
 use arrayvec::ArrayVec;

diff --git a/wgpu-hal/src/gles/queue.rs b/wgpu-hal/src/gles/queue.rs
@@ -1102,10 +1102,10 @@ impl crate::Queue<super::Api> for super::Queue {
         surface: &mut super::Surface,
         texture: super::Texture,
     ) -> Result<(), crate::SurfaceError> {
-        #[cfg(not(target_arch = "wasm32"))]
+        #[cfg(any(not(target_arch = "wasm32"), target_os = "emscripten"))]
         let gl = &self.shared.context.get_without_egl_lock();
 
-        #[cfg(target_arch = "wasm32")]
+        #[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
         let gl = &self.shared.context.glow_context;
 
         surface.present(texture, gl)