Add 'web' feature, add missing feature enables/checks.

Author: raphaelhetzel

examples/standalone/custom_backend/Cargo.toml

@@ -4,6 +4,9 @@ edition = "2021"
 rust-version = "1.84"
 publish = false
 
+[features]
+web = ["wgpu/web"]
+
 [dependencies]
 wgpu = { version = "25.0.0", features = [
     "custom",

examples/standalone/custom_backend/src/custom.rs

@@ -337,7 +337,7 @@ impl QueueInterface for CustomQueue {
         unimplemented!()
     }
 
-    #[cfg(target_arch = "wasm32")]
+    #[cfg(all(target_arch = "wasm32", feature = "web"))]
     fn copy_external_image_to_texture(
         &self,
         _source: &wgpu::CopyExternalImageSourceInfo,

wgpu-hal/Cargo.toml

@@ -118,6 +118,7 @@ gles = [
     "dep:profiling",
     "dep:wasm-bindgen",
     "dep:web-sys",
+    "wgpu-types/web",
     "windows/Win32_Graphics_OpenGL",
     "windows/Win32_Graphics_Gdi",
     "windows/Win32_System_LibraryLoader",

wgpu/Cargo.toml

@@ -48,19 +48,16 @@ gles = ["wgpu-core?/gles"]
 
 ## Enables the WebGPU backend on WebAssembly.
 webgpu = [
+    "web",
     "naga?/wgsl-out",
     "dep:wasm-bindgen-futures",
-    "dep:wasm-bindgen",
-    "dep:js-sys",
-    "dep:web-sys",
     "web-sys/Document",
     "web-sys/Event",
     "web-sys/Navigator",
     "web-sys/NodeList",
     "web-sys/Window",
     "web-sys/WorkerGlobalScope",
     "web-sys/WorkerNavigator",
-    "wgpu-types/web",
 ]
 
 #! ### Conditional Backends
@@ -72,14 +69,7 @@ angle = ["wgpu-core?/angle"]
 vulkan-portability = ["wgpu-core?/vulkan-portability"]
 
 ## Enables the GLES backend on WebAssembly only.
-webgl = [
-    "wgpu-core/webgl",
-    "dep:wgpu-hal",
-    "dep:smallvec",
-    "dep:wasm-bindgen",
-    "dep:js-sys",
-    "dep:web-sys",
-]
+webgl = ["web", "wgpu-core/webgl", "dep:wgpu-hal", "dep:smallvec"]
 
 ## Enables the noop backend for testing.
 ##
@@ -159,6 +149,13 @@ fragile-send-sync-non-atomic-wasm = [
     "wgpu-types/fragile-send-sync-non-atomic-wasm",
 ]
 
+## Use web-specific libraries on WASM
+##
+## Those libraties (wasm-bindgen, web-sys, js-sys) can only be used when there is a JavaScript
+## context around the WASM VM, e.g., when the WASM binary is used in a browser.
+web = ["dep:wasm-bindgen", "dep:js-sys", "dep:web-sys", "wgpu-types/web"]
+
+
 #########################
 # Standard Dependencies #
 #########################

wgpu/build.rs

@@ -2,6 +2,7 @@ fn main() {
     cfg_aliases::cfg_aliases! {
         native: { not(target_arch = "wasm32") },
         Emscripten: { all(target_arch = "wasm32", target_os = "emscripten") },
+        web: { all(target_arch = "wasm32", feature = "web")},
 
         send_sync: { any(
             native,

wgpu/src/api/instance.rs

@@ -303,7 +303,7 @@ impl Instance {
                 surface
             }?,
 
-            #[cfg(any(webgpu, webgl))]
+            #[cfg(web)]
             SurfaceTarget::Canvas(canvas) => {
                 handle_source = None;
 
@@ -322,7 +322,7 @@ impl Instance {
                 }?
             }
 
-            #[cfg(any(webgpu, webgl))]
+            #[cfg(web)]
             SurfaceTarget::OffscreenCanvas(canvas) => {
                 handle_source = None;
 

wgpu/src/api/queue.rs

@@ -232,7 +232,7 @@ impl Queue {
     }
 
     /// Schedule a copy of data from `image` into `texture`.
-    #[cfg(any(webgpu, webgl))]
+    #[cfg(web)]
     pub fn copy_external_image_to_texture(
         &self,
         source: &wgt::CopyExternalImageSourceInfo,

wgpu/src/api/surface.rs

@@ -243,7 +243,7 @@ pub enum SurfaceTarget<'window> {
     ///
     /// - On WebGL2: surface creation will return an error if the browser does not support WebGL2,
     ///   or declines to provide GPU access (such as due to a resource shortage).
-    #[cfg(any(webgpu, webgl))]
+    #[cfg(web)]
     Canvas(web_sys::HtmlCanvasElement),
 
     /// Surface from a `web_sys::OffscreenCanvas`.
@@ -255,7 +255,7 @@ pub enum SurfaceTarget<'window> {
     ///
     /// - On WebGL2: surface creation will return an error if the browser does not support WebGL2,
     ///   or declines to provide GPU access (such as due to a resource shortage).
-    #[cfg(any(webgpu, webgl))]
+    #[cfg(web)]
     OffscreenCanvas(web_sys::OffscreenCanvas),
 }
 

wgpu/src/backend/wgpu_core.rs

@@ -1845,7 +1845,7 @@ impl dispatch::QueueInterface for CoreQueue {
 
     // This method needs to exist if either webgpu or webgl is enabled,
     // but we only actually have an implementation if webgl is enabled.
-    #[cfg(any(webgpu, webgl))]
+    #[cfg(web)]
     #[cfg_attr(not(webgl), expect(unused_variables))]
     fn copy_external_image_to_texture(
         &self,

wgpu/src/dispatch.rs

@@ -210,7 +210,7 @@ pub trait QueueInterface: CommonTraits {
         data_layout: crate::TexelCopyBufferLayout,
         size: crate::Extent3d,
     );
-    #[cfg(any(webgpu, webgl))]
+    #[cfg(web)]
     fn copy_external_image_to_texture(
         &self,
         source: &crate::CopyExternalImageSourceInfo,

wgpu/src/lib.rs

@@ -94,10 +94,10 @@ pub use wgt::{
 pub use wgt::{ImageCopyBuffer, ImageCopyTexture, ImageCopyTextureTagged, ImageDataLayout};
 // wasm-only types, we try to keep as many types non-platform
 // specific, but these need to depend on web-sys.
-#[cfg(any(webgpu, webgl))]
+#[cfg(web)]
 #[expect(deprecated)]
 pub use wgt::ImageCopyExternalImage;
-#[cfg(any(webgpu, webgl))]
+#[cfg(web)]
 pub use wgt::{CopyExternalImageSourceInfo, ExternalImageSource};
 
 /// Re-export of our `naga` dependency.
@@ -119,7 +119,7 @@ pub use raw_window_handle as rwh;
 
 /// Re-export of our `web-sys` dependency.
 ///
-#[cfg(any(webgl, webgpu))]
+#[cfg(web)]
 pub use web_sys;
 
 #[doc(hidden)]