1 files changed, 126 insertions, 0 deletions
diff --git a/src/render_helpers.rs b/src/render_helpers.rs
new file mode 100644
index 00000000..922ff59c
--- /dev/null
+++ b/src/render_helpers.rs
@@ -0,0 +1,126 @@
+use smithay::backend::allocator::dmabuf::Dmabuf;
+use smithay::backend::renderer::element::texture::TextureRenderElement;
+use smithay::backend::renderer::element::{Element, Id, Kind, RenderElement, UnderlyingStorage};
+use smithay::backend::renderer::gles::{GlesError, GlesFrame, GlesRenderer, GlesTexture};
+use smithay::backend::renderer::utils::CommitCounter;
+use smithay::backend::renderer::{Bind, ExportMem, ImportAll, Offscreen, Renderer, Texture};
+use smithay::utils::{Buffer, Physical, Rectangle, Scale, Transform};
+
+/// Trait with our main renderer requirements to save on the typing.
+pub trait NiriRenderer:
+    ImportAll
+    + ExportMem
+    + Bind<Dmabuf>
+    + Offscreen<GlesTexture>
+    + Renderer<TextureId = Self::NiriTextureId, Error = Self::NiriError>
+    + AsGlesRenderer
+{
+    // Associated types to work around the instability of associated type bounds.
+    type NiriTextureId: Texture + Clone + 'static;
+    type NiriError: std::error::Error
+        + Send
+        + Sync
+        + From<<GlesRenderer as Renderer>::Error>
+        + 'static;
+}
+
+impl<R> NiriRenderer for R
+where
+    R: ImportAll + ExportMem + Bind<Dmabuf> + Offscreen<GlesTexture> + AsGlesRenderer,
+    R::TextureId: Texture + Clone + 'static,
+    R::Error: std::error::Error + Send + Sync + From<<GlesRenderer as Renderer>::Error> + 'static,
+{
+    type NiriTextureId = R::TextureId;
+    type NiriError = R::Error;
+}
+
+/// Trait for getting the underlying `GlesRenderer`.
+pub trait AsGlesRenderer {
+    fn as_gles_renderer(&mut self) -> &mut GlesRenderer;
+}
+
+impl AsGlesRenderer for GlesRenderer {
+    fn as_gles_renderer(&mut self) -> &mut GlesRenderer {
+        self
+    }
+}
+
+/// Trait for getting the underlying `GlesFrame`.
+pub trait AsGlesFrame<'frame>
+where
+    Self: 'frame,
+{
+    fn as_gles_frame(&mut self) -> &mut GlesFrame<'frame>;
+}
+
+impl<'frame> AsGlesFrame<'frame> for GlesFrame<'frame> {
+    fn as_gles_frame(&mut self) -> &mut GlesFrame<'frame> {
+        self
+    }
+}
+
+/// Wrapper for a texture from the primary GPU for rendering with the primary GPU.
+#[derive(Debug)]
+pub struct PrimaryGpuTextureRenderElement(pub TextureRenderElement<GlesTexture>);
+
+impl Element for PrimaryGpuTextureRenderElement {
+    fn id(&self) -> &Id {
+        self.0.id()
+    }
+
+    fn current_commit(&self) -> CommitCounter {
+        self.0.current_commit()
+    }
+
+    fn geometry(&self, scale: Scale<f64>) -> Rectangle<i32, Physical> {
+        self.0.geometry(scale)
+    }
+
+    fn transform(&self) -> Transform {
+        self.0.transform()
+    }
+
+    fn src(&self) -> Rectangle<f64, Buffer> {
+        self.0.src()
+    }
+
+    fn damage_since(
+        &self,
+        scale: Scale<f64>,
+        commit: Option<CommitCounter>,
+    ) -> Vec<Rectangle<i32, Physical>> {
+        self.0.damage_since(scale, commit)
+    }
+
+    fn opaque_regions(&self, scale: Scale<f64>) -> Vec<Rectangle<i32, Physical>> {
+        self.0.opaque_regions(scale)
+    }
+
+    fn alpha(&self) -> f32 {
+        self.0.alpha()
+    }
+
+    fn kind(&self) -> Kind {
+        self.0.kind()
+    }
+}
+
+impl RenderElement<GlesRenderer> for PrimaryGpuTextureRenderElement {
+    fn draw(
+        &self,
+        frame: &mut GlesFrame<'_>,
+        src: Rectangle<f64, Buffer>,
+        dst: Rectangle<i32, Physical>,
+        damage: &[Rectangle<i32, Physical>],
+    ) -> Result<(), GlesError> {
+        let gles_frame = frame.as_gles_frame();
+        RenderElement::<GlesRenderer>::draw(&self.0, gles_frame, src, dst, damage)?;
+        Ok(())
+    }
+
+    fn underlying_storage(&self, _renderer: &mut GlesRenderer) -> Option<UnderlyingStorage> {
+        // If scanout for things other than Wayland buffers is implemented, this will need to take
+        // the target GPU into account.
+        None
+    }
+}