1 files changed, 74 insertions, 0 deletions
diff --git a/glow/src/window/compositor.rs b/glow/src/window/compositor.rs
new file mode 100644
index 00000000..2f504ff7
--- /dev/null
+++ b/glow/src/window/compositor.rs
@@ -0,0 +1,74 @@
+use crate::{Backend, Renderer, Settings, Viewport};
+
+use core::ffi::c_void;
+use glow::HasContext;
+use iced_graphics::{Antialiasing, Size};
+use iced_native::mouse;
+
+/// A window graphics backend for iced powered by `glow`.
+#[allow(missing_debug_implementations)]
+pub struct Compositor {
+    gl: glow::Context,
+}
+
+impl iced_graphics::window::GLCompositor for Compositor {
+    type Settings = Settings;
+    type Renderer = Renderer;
+
+    unsafe fn new(
+        settings: Self::Settings,
+        loader_function: impl FnMut(&str) -> *const c_void,
+    ) -> (Self, Self::Renderer) {
+        let gl = glow::Context::from_loader_function(loader_function);
+
+        gl.clear_color(1.0, 1.0, 1.0, 1.0);
+
+        // Enable auto-conversion from/to sRGB
+        gl.enable(glow::FRAMEBUFFER_SRGB);
+
+        // Enable alpha blending
+        gl.enable(glow::BLEND);
+        gl.blend_func(glow::SRC_ALPHA, glow::ONE_MINUS_SRC_ALPHA);
+
+        // Disable multisampling by default
+        gl.disable(glow::MULTISAMPLE);
+
+        let renderer = Renderer::new(Backend::new(&gl, settings));
+
+        (Self { gl }, renderer)
+    }
+
+    fn sample_count(settings: &Settings) -> u32 {
+        settings
+            .antialiasing
+            .map(Antialiasing::sample_count)
+            .unwrap_or(0)
+    }
+
+    fn resize_viewport(&mut self, physical_size: Size<u32>) {
+        unsafe {
+            self.gl.viewport(
+                0,
+                0,
+                physical_size.width as i32,
+                physical_size.height as i32,
+            );
+        }
+    }
+
+    fn draw<T: AsRef<str>>(
+        &mut self,
+        renderer: &mut Self::Renderer,
+        viewport: &Viewport,
+        output: &<Self::Renderer as iced_native::Renderer>::Output,
+        overlay: &[T],
+    ) -> mouse::Interaction {
+        let gl = &self.gl;
+
+        unsafe {
+            gl.clear(glow::COLOR_BUFFER_BIT);
+        }
+
+        renderer.backend_mut().draw(gl, viewport, output, overlay)
+    }
+}