1 files changed, 119 insertions, 0 deletions
diff --git a/wgpu/src/window/compositor.rs b/wgpu/src/window/compositor.rs
new file mode 100644
index 00000000..8950ffd4
--- /dev/null
+++ b/wgpu/src/window/compositor.rs
@@ -0,0 +1,119 @@
+use crate::{window::SwapChain, Renderer, Settings, Target};
+
+use iced_native::{futures, mouse};
+use raw_window_handle::HasRawWindowHandle;
+
+/// A window graphics backend for iced powered by `wgpu`.
+#[derive(Debug)]
+pub struct Compositor {
+    device: wgpu::Device,
+    queue: wgpu::Queue,
+    format: wgpu::TextureFormat,
+}
+
+impl iced_native::window::Compositor for Compositor {
+    type Settings = Settings;
+    type Renderer = Renderer;
+    type Surface = wgpu::Surface;
+    type SwapChain = SwapChain;
+
+    fn new(settings: Self::Settings) -> Self {
+        let (device, queue) = futures::executor::block_on(async {
+            let adapter = wgpu::Adapter::request(
+                &wgpu::RequestAdapterOptions {
+                    power_preference: if settings.antialiasing.is_none() {
+                        wgpu::PowerPreference::Default
+                    } else {
+                        wgpu::PowerPreference::HighPerformance
+                    },
+                    compatible_surface: None,
+                },
+                wgpu::BackendBit::PRIMARY,
+            )
+            .await
+            .expect("Request adapter");
+
+            adapter
+                .request_device(&wgpu::DeviceDescriptor {
+                    extensions: wgpu::Extensions {
+                        anisotropic_filtering: false,
+                    },
+                    limits: wgpu::Limits { max_bind_groups: 2 },
+                })
+                .await
+        });
+
+        Self {
+            device,
+            queue,
+            format: settings.format,
+        }
+    }
+
+    fn create_renderer(&mut self, settings: Settings) -> Renderer {
+        Renderer::new(crate::Backend::new(&mut self.device, settings))
+    }
+
+    fn create_surface<W: HasRawWindowHandle>(
+        &mut self,
+        window: &W,
+    ) -> wgpu::Surface {
+        wgpu::Surface::create(window)
+    }
+
+    fn create_swap_chain(
+        &mut self,
+        surface: &Self::Surface,
+        width: u32,
+        height: u32,
+    ) -> SwapChain {
+        SwapChain::new(&self.device, surface, self.format, width, height)
+    }
+
+    fn draw<T: AsRef<str>>(
+        &mut self,
+        renderer: &mut Self::Renderer,
+        swap_chain: &mut SwapChain,
+        output: &<Self::Renderer as iced_native::Renderer>::Output,
+        scale_factor: f64,
+        overlay: &[T],
+    ) -> mouse::Interaction {
+        let (frame, viewport) = swap_chain.next_frame().expect("Next frame");
+
+        let mut encoder = self.device.create_command_encoder(
+            &wgpu::CommandEncoderDescriptor { label: None },
+        );
+
+        let _ = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+            color_attachments: &[wgpu::RenderPassColorAttachmentDescriptor {
+                attachment: &frame.view,
+                resolve_target: None,
+                load_op: wgpu::LoadOp::Clear,
+                store_op: wgpu::StoreOp::Store,
+                clear_color: wgpu::Color {
+                    r: 1.0,
+                    g: 1.0,
+                    b: 1.0,
+                    a: 1.0,
+                },
+            }],
+            depth_stencil_attachment: None,
+        });
+
+        let mouse_interaction = renderer.backend_mut().draw(
+            &mut self.device,
+            &mut encoder,
+            Target {
+                texture: &frame.view,
+                viewport,
+            },
+            output,
+            scale_factor,
+            overlay,
+        );
+
+        self.queue.submit(&[encoder.finish()]);
+
+        mouse_interaction
+    }
+}