Fix expecting always Rgba8Unorm backbuffer on Web & Bgra8Unorm on nat…

…ive (#1413)

.vscode/settings.json

@@ -24,13 +24,15 @@
     "cSpell.words": [
         "andreas",
         "bbox",
+        "framebuffer",
         "hoverable",
         "Keypoint",
         "memoffset",
         "nyud",
         "objectron",
         "Skybox",
         "smallvec",
+        "swapchain",
         "texcoords",
         "Tonemapper",
         "tonemapping",

crates/re_renderer/examples/framework.rs

@@ -89,6 +89,19 @@ struct Application<E> {
     re_ctx: RenderContext,
 }
 
+// Same as egui_wgpu::preferred_framebuffer_format
+fn preferred_framebuffer_format(formats: &[wgpu::TextureFormat]) -> wgpu::TextureFormat {
+    for &format in formats {
+        if matches!(
+            format,
+            wgpu::TextureFormat::Rgba8Unorm | wgpu::TextureFormat::Bgra8Unorm
+        ) {
+            return format;
+        }
+    }
+    formats[0] // take the first
+}
+
 impl<E: Example + 'static> Application<E> {
     async fn new(event_loop: EventLoop<()>, window: Window) -> anyhow::Result<Self> {
         let size = window.inner_size();
@@ -124,13 +137,8 @@ impl<E: Example + 'static> Application<E> {
         let device = Arc::new(device);
         let queue = Arc::new(queue);
 
-        // re_renderer is doing its own srgb conversion for each ViewBuilder for better egui compatibility.
-        let swapchain_format = if cfg!(target_arch = "wasm32") {
-            wgpu::TextureFormat::Rgba8Unorm
-        } else {
-            wgpu::TextureFormat::Bgra8Unorm
-        };
-
+        let swapchain_format =
+            preferred_framebuffer_format(&surface.get_capabilities(&adapter).formats);
         let surface_config = wgpu::SurfaceConfiguration {
             usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
             format: swapchain_format,

crates/re_viewer/src/lib.rs

@@ -129,18 +129,11 @@ pub(crate) fn customize_eframe(cc: &eframe::CreationContext<'_>) -> re_ui::ReUi
 
         let paint_callback_resources = &mut render_state.renderer.write().paint_callback_resources;
 
-        // TODO(andreas): Query used surface format from eframe/renderer.
-        let output_format_color = if cfg!(target_arch = "wasm32") {
-            wgpu::TextureFormat::Rgba8Unorm
-        } else {
-            wgpu::TextureFormat::Bgra8Unorm
-        };
-
         paint_callback_resources.insert(RenderContext::new(
             render_state.device.clone(),
             render_state.queue.clone(),
             RenderContextConfig {
-                output_format_color,
+                output_format_color: render_state.target_format,
                 hardware_tier: crate::hardware_tier(),
             },
         ));