Implement WebGL2 Backend (#1686)

* Implement WebGL Backend * Add WebGL Fixes by @mrk-its * Update Limits for WASM and Examples * Address Review Points
gfx-rs · Oct 7, 2021 · 312828f · 312828f
1 parent c36e080
commit 312828f
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diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -130,6 +130,9 @@ jobs:
         run: |
           cargo clippy --target ${{ matrix.target }} -p wgpu
 
+          # Build for WebGL
+          cargo clippy --target ${{ matrix.target }} -p wgpu --features webgl -- -D warnings
+
           # build docs
           cargo doc --target ${{ matrix.target }} -p wgpu --no-deps
 

diff --git a/run-wasm-example.sh b/run-wasm-example.sh
@@ -0,0 +1,34 @@
+#!/bin/env bash
+
+set -e
+
+echo "Compiling..."
+cargo build --example $1 --target wasm32-unknown-unknown --features webgl
+
+echo "Generating bindings..."
+mkdir -p target/wasm-examples/$1
+wasm-bindgen --target web --out-dir target/wasm-examples/$1 target/wasm32-unknown-unknown/debug/examples/$1.wasm
+cp wasm-resources/index.template.html target/wasm-examples/$1/index.html
+sed -i "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/README.md b/wasm-resources/README.md
@@ -0,0 +1,3 @@
+# WASM Resources
+
+This directory contains resources used when building the WGPU examples for web.
diff --git a/wasm-resources/index.template.html b/wasm-resources/index.template.html
@@ -0,0 +1,14 @@
+<html>
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  </head>
+  <body>
+    <script type="module">
+      import init from "./{{example}}.js";
+      window.addEventListener("load", () => {
+        init();
+      });
+    </script>
+  </body>
+</html>
diff --git a/wgpu-core/Cargo.toml b/wgpu-core/Cargo.toml
@@ -50,6 +50,9 @@ path = "../wgpu-hal"
 package = "wgpu-hal"
 version = "0.10.1"
 
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+hal = { path = "../wgpu-hal", package = "wgpu-hal", version = "0.10", features = ["gles"] }
+
 [target.'cfg(all(not(target_arch = "wasm32"), any(target_os = "ios", target_os = "macos")))'.dependencies]
 hal = { path = "../wgpu-hal", package = "wgpu-hal", version = "0.10", features = ["metal"] }
 #Note: could also enable "vulkan" for Vulkan Portability

diff --git a/wgpu-core/build.rs b/wgpu-core/build.rs
@@ -11,6 +11,11 @@ fn main() {
         metal: { all(not(wasm), apple) },
         dx12: { all(not(wasm), windows) },
         dx11: { all(false, not(wasm), windows) },
-        gl: { all(not(wasm), unix_wo_apple) },
+        gl: {
+            any(
+                all(not(wasm), unix_wo_apple),
+                wasm
+            )
+        },
     }
 }
diff --git a/wgpu-core/src/device/mod.rs b/wgpu-core/src/device/mod.rs
@@ -4584,6 +4584,10 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         {
             self.poll_devices::<hal::api::Dx11>(force_wait, &mut closures)?;
         }
+        #[cfg(gl)]
+        {
+            self.poll_devices::<hal::api::Gles>(force_wait, &mut closures)?;
+        }
 
         unsafe {
             closures.fire();

diff --git a/wgpu-core/src/hub.rs b/wgpu-core/src/hub.rs
@@ -1022,6 +1022,7 @@ impl HalApi for hal::api::Dx11 {
 impl HalApi for hal::api::Gles {
     const VARIANT: Backend = Backend::Gl;
     fn create_instance_from_hal(name: &str, hal_instance: Self::Instance) -> Instance {
+        #[allow(clippy::needless_update)]
         Instance {
             name: name.to_owned(),
             gl: Some(hal_instance),

diff --git a/wgpu-core/src/lib.rs b/wgpu-core/src/lib.rs
@@ -45,7 +45,7 @@ pub mod resource;
 mod track;
 mod validation;
 
-pub use hal::api;
+pub use hal::{api, MAX_BIND_GROUPS, MAX_COLOR_TARGETS, MAX_VERTEX_BUFFERS};
 
 use atomic::{AtomicUsize, Ordering};
 
@@ -211,7 +211,10 @@ macro_rules! gfx_select {
             wgt::Backend::Dx12 => $global.$method::<$crate::api::Dx12>( $($param),* ),
             //#[cfg(all(not(target_arch = "wasm32"), windows))]
             //wgt::Backend::Dx11 => $global.$method::<$crate::api::Dx11>( $($param),* ),
-            #[cfg(all(not(target_arch = "wasm32"), unix, not(any(target_os = "ios", target_os = "macos"))))]
+            #[cfg(any(
+                all(unix, not(target_os = "macos"), not(target_os = "ios")),
+                target_arch = "wasm32"
+            ))]
             wgt::Backend::Gl => $global.$method::<$crate::api::Gles>( $($param),+ ),
             other => panic!("Unexpected backend {:?}", other),
 

diff --git a/wgpu-hal/Cargo.toml b/wgpu-hal/Cargo.toml
@@ -68,6 +68,11 @@ mtl = { package = "metal", version = "0.23.1" }
 objc = "0.2.5"
 core-graphics-types = "0.1"
 
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+wasm-bindgen = { version = "0.2" }
+web-sys = { version = "0.3", features = ["Window", "HtmlCanvasElement", "WebGl2RenderingContext"] }
+js-sys = { version = "0.3" }
+
 [dependencies.naga]
 git = "https://github.com/gfx-rs/naga"
 rev = "2e7d629"

diff --git a/wgpu-hal/src/gles/adapter.rs b/wgpu-hal/src/gles/adapter.rs
@@ -192,7 +192,7 @@ impl super::Adapter {
 
         let shading_language_version = {
             let sl_version = gl.get_parameter_string(glow::SHADING_LANGUAGE_VERSION);
-            log::info!("SL version: {}", sl_version);
+            log::info!("SL version: {}", &sl_version);
             let (sl_major, sl_minor) = Self::parse_version(&sl_version).ok()?;
             let value = sl_major as u16 * 100 + sl_minor as u16 * 10;
             naga::back::glsl::Version::Embedded(value)
@@ -209,9 +209,11 @@ impl super::Adapter {
         let max_storage_block_size =
             gl.get_parameter_i32(glow::MAX_SHADER_STORAGE_BLOCK_SIZE) as u32;
 
-        // WORKAROUND:
-        // In order to work around an issue with GL on RPI4 and similar, we ignore a zero vertex ssbo count if there are vertex sstos. (more info: https://github.com/gfx-rs/wgpu/pull/1607#issuecomment-874938961)
-        // The hardware does not want us to write to these SSBOs, but GLES cannot express that. We detect this case and disable writing to SSBOs.
+        // WORKAROUND: In order to work around an issue with GL on RPI4 and similar, we ignore a
+        // zero vertex ssbo count if there are vertex sstos. (more info:
+        // https://github.com/gfx-rs/wgpu/pull/1607#issuecomment-874938961) The hardware does not
+        // want us to write to these SSBOs, but GLES cannot express that. We detect this case and
+        // disable writing to SSBOs.
         let vertex_ssbo_false_zero =
             vertex_shader_storage_blocks == 0 && vertex_shader_storage_textures != 0;
         if vertex_ssbo_false_zero {
@@ -254,6 +256,7 @@ impl super::Adapter {
                 && max_storage_block_size != 0
                 && (vertex_shader_storage_blocks != 0 || vertex_ssbo_false_zero),
         );
+        downlevel_flags.set(wgt::DownlevelFlags::FRAGMENT_STORAGE, ver >= (3, 1));
 
         let mut features = wgt::Features::empty()
             | wgt::Features::TEXTURE_COMPRESSION_ETC2
@@ -283,6 +286,14 @@ impl super::Adapter {
             super::PrivateCapabilities::VERTEX_BUFFER_LAYOUT,
             ver >= (3, 1),
         );
+        private_caps.set(
+            super::PrivateCapabilities::INDEX_BUFFER_ROLE_CHANGE,
+            cfg!(not(target_arch = "wasm32")),
+        );
+        private_caps.set(
+            super::PrivateCapabilities::CAN_DISABLE_DRAW_BUFFER,
+            cfg!(not(target_arch = "wasm32")),
+        );
 
         let max_texture_size = gl.get_parameter_i32(glow::MAX_TEXTURE_SIZE) as u32;
         let max_texture_3d_size = gl.get_parameter_i32(glow::MAX_3D_TEXTURE_SIZE) as u32;
@@ -340,6 +351,12 @@ impl super::Adapter {
         };
 
         let mut workarounds = super::Workarounds::empty();
+
+        workarounds.set(
+            super::Workarounds::EMULATE_BUFFER_MAP,
+            cfg!(target_arch = "wasm32"),
+        );
+
         let r = renderer.to_lowercase();
         // Check for Mesa sRGB clear bug. See
         // [`super::PrivateCapabilities::MESA_I915_SRGB_SHADER_CLEAR`].
@@ -358,13 +375,17 @@ impl super::Adapter {
         let downlevel_defaults = wgt::DownlevelLimits {};
 
         // Drop the GL guard so we can move the context into AdapterShared
+        // ( on WASM the gl handle is just a ref so we tell clippy to allow
+        // dropping the ref )
+        #[allow(clippy::drop_ref)]
         drop(gl);
 
         Some(crate::ExposedAdapter {
             adapter: super::Adapter {
                 shared: Arc::new(super::AdapterShared {
                     context,
                     private_caps,
+                    downlevel_flags,
                     workarounds,
                     shading_language_version,
                 }),
@@ -462,6 +483,7 @@ impl crate::Adapter<super::Api> for super::Adapter {
                 zero_buffer,
                 temp_query_results: Vec::new(),
                 draw_buffer_count: 1,
+                current_index_buffer: None,
             },
         })
     }
@@ -561,11 +583,13 @@ impl crate::Adapter<super::Api> for super::Adapter {
                 formats: if surface.enable_srgb {
                     vec![
                         wgt::TextureFormat::Rgba8UnormSrgb,
+                        #[cfg(not(target_arch = "wasm32"))]
                         wgt::TextureFormat::Bgra8UnormSrgb,
                     ]
                 } else {
                     vec![
                         wgt::TextureFormat::Rgba8Unorm,
+                        #[cfg(not(target_arch = "wasm32"))]
                         wgt::TextureFormat::Bgra8Unorm,
                     ]
                 },
@@ -590,6 +614,12 @@ impl crate::Adapter<super::Api> for super::Adapter {
     }
 }
 
+// SAFE: WASM doesn't have threads
+#[cfg(target_arch = "wasm32")]
+unsafe impl Sync for super::Adapter {}
+#[cfg(target_arch = "wasm32")]
+unsafe impl Send for super::Adapter {}
+
 #[cfg(test)]
 mod tests {
     use super::super::Adapter;

diff --git a/wgpu-hal/src/gles/command.rs b/wgpu-hal/src/gles/command.rs
@@ -266,14 +266,17 @@ impl crate::CommandEncoder<super::Api> for super::CommandEncoder {
     ) where
         T: Iterator<Item = crate::BufferCopy>,
     {
-        //TODO: preserve `src.target` and `dst.target`
-        // at least for the buffers that require it.
+        let (src_target, dst_target) = if src.target == dst.target {
+            (glow::COPY_READ_BUFFER, glow::COPY_WRITE_BUFFER)
+        } else {
+            (src.target, dst.target)
+        };
         for copy in regions {
             self.cmd_buffer.commands.push(C::CopyBufferToBuffer {
                 src: src.raw,
-                src_target: glow::COPY_READ_BUFFER,
+                src_target,
                 dst: dst.raw,
-                dst_target: glow::COPY_WRITE_BUFFER,
+                dst_target,
                 copy,
             })
         }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		# WASM Resources

		This directory contains resources used when building the WGPU examples for web.