configure context

lib/context.rs

@@ -59,4 +59,40 @@ impl Context {
             queue,
         })
     }
+
+    /// Configures the surface with a render format and alpha mode for rendering.
+    /// Inputs: adapter (GPU capabilities), width/height (surface resolution).
+    /// Returns Ok(()) on success or SurfaceIncompatible if no SRGB format + alpha mode exist.
+    /// Typically called by the renderer when window size changes.
+    pub fn configure(&self, adapter: &wgpu::Adapter, width: u32, height: u32) -> Result<(), WsgError> {
+        let caps = self.surface.get_capabilities(adapter);
+        // Prefer SRGB format for color accuracy; fall back to first available if none (technical point documented above).
+        let format = caps
+            .formats
+            .iter()
+            .copied()
+            .find(|f| f.is_srgb())
+            .or(caps.formats.first().copied())
+            .ok_or(WsgError::SurfaceIncompatible)?;
+
+        let alpha_mode = caps
+            .alpha_modes
+            .first()
+            .copied()
+            .ok_or(WsgError::SurfaceIncompatible)?;
+
+        let config = wgpu::SurfaceConfiguration {
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
+            format,
+            width,
+            height,
+            present_mode: wgpu::PresentMode::Fifo, // V-Sync activated
+            alpha_mode,                            // first supported alpha mode
+            view_formats: vec![],
+            color_space: wgpu::SurfaceColorSpace::Srgb,
+            desired_maximum_frame_latency: 2,
+        };
+        self.surface.configure(&self.device, &config);
+        Ok(())
+    }
 }

lib/error.rs

@@ -45,4 +45,9 @@ pub enum WsgError {
     /// Caller: `Context::new()` after `Instance::create_surface()`.
     #[error("Failed to create rendering surface")]
     SurfaceCreation(wgpu::CreateSurfaceError),
+
+    /// The surface is incompatible — no SRGB texture format and alpha mode are available on the device.
+    /// Caller: `Context::configure()` when selecting a render format/alpha mode from surface capabilities.
+    #[error("No compatible render format or alpha mode found for the surface")]
+    SurfaceIncompatible,
 }