From 4132183bd391467e4a572a8e2b8265fe9a87c9cb Mon Sep 17 00:00:00 2001
From: Guilherme Werner <guilherme.werner@tribufu.com>
Date: Fri, 16 Feb 2024 19:56:32 -0300
Subject: [PATCH] Create wgpu surface

---
 Cargo.toml          |   4 +
 examples/index.html |   7 +-
 src/lib.rs          | 226 ++++++++++++++++++++++++++++++++++++++++----
 src/main.rs         |   7 +-
 4 files changed, 221 insertions(+), 23 deletions(-)
diff --git a/Cargo.toml b/Cargo.toml
index 593721a..da64b5d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,12 +17,16 @@ name = "renderer"
 path = "src/main.rs"
 
 [dependencies]
+anyhow = "1.0"
 cfg-if = "1"
 env_logger = "0.10"
 log = "0.4"
 wgpu = "0.18"
 winit = "0.28"
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+tokio = { version = "1.36.0", features = ["full"] }
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 console_error_panic_hook = "0.1.6"
 console_log = "1.0"
diff --git a/examples/index.html b/examples/index.html
index 091656c..c0d9484 100644
--- a/examples/index.html
+++ b/examples/index.html
@@ -7,13 +7,18 @@
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <style>
+        body {
+            margin: 0;
+            padding: 0;
+        }
+
         canvas {
             background-color: black;
         }
     </style>
 </head>
 
-<body id="wasm-example">
+<body id="wasm-surface">
     <script type="module">
         import init from "../package/renderer.js";
 
diff --git a/src/lib.rs b/src/lib.rs
index 5b33904..6aa472b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,14 +2,14 @@ use winit::{
     dpi::LogicalSize,
     event::*,
     event_loop::{ControlFlow, EventLoop},
-    window::WindowBuilder,
+    window::{Window, WindowBuilder},
 };
 
 #[cfg(target_arch = "wasm32")]
 use wasm_bindgen::prelude::*;
 
 #[cfg_attr(target_arch = "wasm32", wasm_bindgen(start))]
-pub fn run() {
+pub async fn run() {
     cfg_if::cfg_if! {
         if #[cfg(target_arch = "wasm32")] {
             std::panic::set_hook(Box::new(console_error_panic_hook::hook));
@@ -32,7 +32,7 @@ pub fn run() {
         web_sys::window()
             .and_then(|win| win.document())
             .and_then(|doc| {
-                let dst = doc.get_element_by_id("wasm-example")?;
+                let dst = doc.get_element_by_id("wasm-surface")?;
                 let canvas = web_sys::Element::from(window.canvas());
                 dst.append_child(&canvas).ok()?;
                 Some(())
@@ -40,23 +40,209 @@ pub fn run() {
             .expect("Couldn't append canvas to document body.");
     }
 
-    event_loop.run(move |event, _, control_flow| match event {
-        Event::WindowEvent {
-            ref event,
-            window_id,
-        } if window_id == window.id() => match event {
-            WindowEvent::CloseRequested
-            | WindowEvent::KeyboardInput {
-                input:
-                    KeyboardInput {
-                        state: ElementState::Pressed,
-                        virtual_keycode: Some(VirtualKeyCode::Escape),
-                        ..
-                    },
-                ..
-            } => *control_flow = ControlFlow::Exit,
+    let mut state = State::new(window).await;
+
+    event_loop.run(move |event, _, control_flow| {
+        match event {
+            Event::WindowEvent {
+                ref event,
+                window_id,
+            } if window_id == state.window().id() => {
+                if !state.input(event) {
+                    // UPDATED!
+                    match event {
+                        WindowEvent::CloseRequested
+                        | WindowEvent::KeyboardInput {
+                            input:
+                                KeyboardInput {
+                                    state: ElementState::Pressed,
+                                    virtual_keycode: Some(VirtualKeyCode::Escape),
+                                    ..
+                                },
+                            ..
+                        } => *control_flow = ControlFlow::Exit,
+                        WindowEvent::Resized(physical_size) => {
+                            state.resize(*physical_size);
+                        }
+                        WindowEvent::ScaleFactorChanged { new_inner_size, .. } => {
+                            state.resize(**new_inner_size);
+                        }
+                        _ => {}
+                    }
+                }
+            }
+            Event::RedrawRequested(window_id) if window_id == state.window().id() => {
+                state.update();
+                match state.render() {
+                    Ok(_) => {}
+                    // Reconfigure the surface if lost
+                    Err(wgpu::SurfaceError::Lost) => state.resize(state.size),
+                    // The system is out of memory, we should probably quit
+                    Err(wgpu::SurfaceError::OutOfMemory) => *control_flow = ControlFlow::Exit,
+                    // All other errors (Outdated, Timeout) should be resolved by the next frame
+                    Err(e) => eprintln!("{:?}", e),
+                }
+            }
+            Event::MainEventsCleared => {
+                // RedrawRequested will only trigger once unless we manually
+                // request it.
+                state.window().request_redraw();
+            }
             _ => {}
-        },
-        _ => {}
+        }
     });
 }
+
+pub struct State {
+    surface: wgpu::Surface,
+    device: wgpu::Device,
+    queue: wgpu::Queue,
+    config: wgpu::SurfaceConfiguration,
+    size: winit::dpi::PhysicalSize<u32>,
+    // The window must be declared after the surface so
+    // it gets dropped after it as the surface contains
+    // unsafe references to the window's resources.
+    window: Window,
+}
+
+impl State {
+    // Creating some of the wgpu types requires async code
+    async fn new(window: Window) -> Self {
+        let size = window.inner_size();
+
+        // The instance is a handle to our GPU
+        // Backends::all => Vulkan + Metal + DX12 + Browser WebGPU
+        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
+            backends: wgpu::Backends::all(),
+            ..Default::default()
+        });
+
+        // # Safety
+        //
+        // The surface needs to live as long as the window that created it.
+        // State owns the window, so this should be safe.
+        let surface = unsafe { instance.create_surface(&window) }.unwrap();
+
+        let adapter = instance
+            .request_adapter(&wgpu::RequestAdapterOptions {
+                power_preference: wgpu::PowerPreference::default(),
+                compatible_surface: Some(&surface),
+                force_fallback_adapter: false,
+            })
+            .await
+            .unwrap();
+
+        let (device, queue) = adapter
+            .request_device(
+                &wgpu::DeviceDescriptor {
+                    features: wgpu::Features::empty(),
+                    // WebGL doesn't support all of wgpu's features, so if
+                    // we're building for the web, we'll have to disable some.
+                    limits: if cfg!(target_arch = "wasm32") {
+                        wgpu::Limits::downlevel_webgl2_defaults()
+                    } else {
+                        wgpu::Limits::default()
+                    },
+                    label: None,
+                },
+                None, // Trace path
+            )
+            .await
+            .unwrap();
+
+        let surface_caps = surface.get_capabilities(&adapter);
+
+        // Shader code in this tutorial assumes an sRGB surface texture. Using a different
+        // one will result in all the colors coming out darker. If you want to support non
+        // sRGB surfaces, you'll need to account for that when drawing to the frame.
+        let surface_format = surface_caps
+            .formats
+            .iter()
+            .copied()
+            .filter(|f| f.is_srgb())
+            .next()
+            .unwrap_or(surface_caps.formats[0]);
+
+        let config = wgpu::SurfaceConfiguration {
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
+            format: surface_format,
+            width: size.width,
+            height: size.height,
+            present_mode: surface_caps.present_modes[0],
+            alpha_mode: surface_caps.alpha_modes[0],
+            view_formats: vec![],
+        };
+
+        surface.configure(&device, &config);
+
+        Self {
+            window,
+            surface,
+            device,
+            queue,
+            config,
+            size,
+        }
+    }
+
+    pub fn window(&self) -> &Window {
+        &self.window
+    }
+
+    pub fn resize(&mut self, new_size: winit::dpi::PhysicalSize<u32>) {
+        if new_size.width > 0 && new_size.height > 0 {
+            self.size = new_size;
+            self.config.width = new_size.width;
+            self.config.height = new_size.height;
+            self.surface.configure(&self.device, &self.config);
+        }
+    }
+
+    fn input(&mut self, event: &WindowEvent) -> bool {
+        false
+    }
+
+    fn update(&mut self) {}
+
+    fn render(&mut self) -> Result<(), wgpu::SurfaceError> {
+        let output = self.surface.get_current_texture()?;
+
+        let view = output
+            .texture
+            .create_view(&wgpu::TextureViewDescriptor::default());
+
+        let mut encoder = self
+            .device
+            .create_command_encoder(&wgpu::CommandEncoderDescriptor {
+                label: Some("Render Encoder"),
+            });
+
+        {
+            let _render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                label: Some("Render Pass"),
+                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+                    view: &view,
+                    resolve_target: None,
+                    ops: wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(wgpu::Color {
+                            r: 0.1,
+                            g: 0.2,
+                            b: 0.3,
+                            a: 1.0,
+                        }),
+                        store: wgpu::StoreOp::Store,
+                    },
+                })],
+                depth_stencil_attachment: None,
+                occlusion_query_set: None,
+                timestamp_writes: None,
+            });
+        }
+
+        // submit will accept anything that implements IntoIter
+        self.queue.submit(std::iter::once(encoder.finish()));
+        output.present();
+
+        Ok(())
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 58cc21c..5d7aceb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,8 @@
+use anyhow::Result;
 use renderer::run;
 
-fn main() {
-    run();
+#[tokio::main]
+async fn main() -> Result<()> {
+    run().await;
+    Ok(())
 }
