renderer: Account for OpenGLs coordinate system in the Gles2Renderer

CHANGELOG.md

@@ -33,6 +33,7 @@
 - `X11Surface` is now multi-window capable.
 - `Renderer::clear` now expects a second argument to optionally only clear parts of the buffer/surface
 - `Transform::transform_size` now takes a `Size` instead of two `u32`
+- `Gles2Renderer` now automatically flips the `render` result to account for OpenGLs coordinate system
 
 ### Additions
 

anvil/src/udev.rs

@@ -743,18 +743,8 @@ fn render_surface(
 
     // and draw to our buffer
     match renderer
-        .render(
+        .render(mode.size, Transform::Normal, |renderer, frame| {
-            mode.size,
+            render_layers_and_windows(renderer, frame, window_map, output_geometry, output_scale, logger)?;
-            Transform::Flipped180, // Scanout is rotated
-            |renderer, frame| {
-                render_layers_and_windows(
-                    renderer,
-                    frame,
-                    window_map,
-                    output_geometry,
-                    output_scale,
-                    logger,
-                )?;
 
             // set cursor
             if output_geometry.to_f64().contains(pointer_location) {
@@ -827,8 +817,7 @@ fn render_surface(
             }
 
             Ok(())
-            },
+        })
-        )
         .map_err(Into::<SwapBuffersError>::into)
         .and_then(|x| x)
         .map_err(Into::<SwapBuffersError>::into)

anvil/src/x11.rs

@@ -239,12 +239,8 @@ pub fn run_x11(log: Logger) {
 
             // drawing logic
             match renderer
-                // X11 scanout for a Dmabuf is upside down
                 // TODO: Address this issue in renderer.
-                .render(
+                .render(backend_data.mode.size, Transform::Normal, |renderer, frame| {
-                    backend_data.mode.size,
-                    Transform::Flipped180,
-                    |renderer, frame| {
                     render_layers_and_windows(
                         renderer,
                         frame,
@@ -309,8 +305,7 @@ pub fn run_x11(log: Logger) {
                     }
 
                     Ok(())
-                    },
+                })
-                )
                 .map_err(Into::<SwapBuffersError>::into)
                 .and_then(|x| x)
                 .map_err(Into::<SwapBuffersError>::into)

src/backend/renderer/gles2/mod.rs

@@ -1077,11 +1077,14 @@ impl Renderer for Gles2Renderer {
         renderer[2][0] = -(1.0f32.copysign(renderer[0][0] + renderer[1][0]));
         renderer[2][1] = -(1.0f32.copysign(renderer[0][1] + renderer[1][1]));
 
+        // We account for OpenGLs coordinate system here
+        let flip180 = Matrix3::new(1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 1.0);
+
         let mut frame = Gles2Frame {
             gl: self.gl.clone(),
             programs: self.programs.clone(),
             // output transformation passed in by the user
-            current_projection: transform.matrix() * renderer,
+            current_projection: flip180 * transform.matrix() * renderer,
         };
 
         let result = rendering(self, &mut frame);

src/backend/winit/mod.rs

@@ -298,7 +298,8 @@ impl WinitGraphicsBackend {
         };
 
         self.renderer.bind(self.egl.clone())?;
-        let result = self.renderer.render(size, Transform::Normal, rendering)?;
+        // Why is winit falling out of place with the coordinate system?
+        let result = self.renderer.render(size, Transform::Flipped180, rendering)?;
         self.egl.swap_buffers()?;
         self.renderer.unbind()?;
         Ok(result)