wgpu backend: Enable WebGL fallback (#8038)

* Fix for https://github.com/emilk/eframe_template/issues/223
* Related: https://github.com/gfx-rs/wgpu/pull/9319

By default, we would only turn on the WebGPU backend on web, which means
browsers without WebGPU support would just crash.

You can still opt-out of all the default `wgpu` features by enabling
`eframe/wgpu_no_default_features` instead of `eframe/wgpu`

Cargo.lock

@@ -1330,7 +1330,6 @@ dependencies = [
  "wasm-bindgen",
  "wasm-bindgen-futures",
  "web-sys",
- "wgpu",
 ]
 
 [[package]]

crates/eframe/Cargo.toml

@@ -89,7 +89,7 @@ web_screen_reader = ["web-sys/SpeechSynthesis", "web-sys/SpeechSynthesisUtteranc
 ## See <https://github.com/emilk/egui/issues/5889> for more details.
 ##
 ## By default, eframe will prefer WebGPU over WebGL, but
-## you can configure this at run-time with [`NativeOptions::wgpu_options`].
+## you can configure this at run-time with `WebOptions::wgpu_options`.
 wgpu = ["wgpu_no_default_features", "egui-wgpu/default"]
 
 ## This is exactly like the `wgpu` feature, but does NOT enable the default features of `wgpu` and `egui-wgpu`.
@@ -155,7 +155,6 @@ glutin-winit = { workspace = true, optional = true, default-features = false, fe
   "wgl",
 ] }
 home = { workspace = true, optional = true }
-wgpu = { workspace = true, optional = true }
 
 # mac:
 [target.'cfg(any(target_os = "macos"))'.dependencies]

crates/eframe/src/lib.rs

@@ -159,7 +159,7 @@ pub use {egui, egui::emath, egui::epaint};
 pub use {egui_glow, glow};
 
 #[cfg(feature = "wgpu_no_default_features")]
-pub use {egui_wgpu, wgpu};
+pub use {egui_wgpu, egui_wgpu::wgpu};
 
 mod epi;
 

crates/egui-wgpu/Cargo.toml

@@ -25,7 +25,12 @@ all-features = true
 rustdoc-args = ["--generate-link-to-definition"]
 
 [features]
-default = ["fragile-send-sync-non-atomic-wasm", "macos-window-resize-jitter-fix", "wgpu/default"]
+default = [
+  "fragile-send-sync-non-atomic-wasm",
+  "macos-window-resize-jitter-fix",
+  "wgpu/default",
+  "wgpu/webgl", # A very important fallback for web support
+]
 
 ## Enables the `capture` module for capturing screenshots.
 capture = ["dep:egui"]

crates/egui_demo_app/Cargo.toml

@@ -37,7 +37,7 @@ serde = ["dep:serde", "egui_demo_lib/serde", "egui/serde"]
 syntect = ["egui_demo_lib/syntect"]
 
 glow = ["eframe/glow"]
-wgpu = ["eframe/wgpu", "bytemuck", "dep:wgpu"]
+wgpu = ["eframe/wgpu", "bytemuck"]
 wayland = ["eframe/wayland"]
 x11 = ["eframe/x11"]
 
@@ -60,9 +60,6 @@ accesskit_consumer = { workspace = true, optional = true }
 bytemuck = { workspace = true, optional = true }
 puffin = { workspace = true, optional = true }
 puffin_http = { workspace = true, optional = true }
-# Enable both WebGL & WebGPU when targeting the web (these features have no effect when not targeting wasm32)
-# Also enable the default features so we have a supported backend for every platform.
-wgpu = { workspace = true, features = ["default", "webgpu", "webgl"], optional = true }
 
 
 # feature "http":

crates/egui_demo_app/src/backend_panel.rs

@@ -211,7 +211,7 @@ fn integration_ui(ui: &mut egui::Ui, _frame: &mut eframe::Frame) {
         let wgpu_adapter_details_ui = |ui: &mut egui::Ui, adapter: &eframe::wgpu::Adapter| {
             let info = &adapter.get_info();
 
-            let wgpu::AdapterInfo {
+            let eframe::wgpu::AdapterInfo {
                 name,
                 vendor,
                 device,