Cache texture in OpenAnimation

Don't recreate it unless the size changes. This lays the groundwork for also
tracking damage in the future.

2 files changed, 96 insertions, 220 deletions

diff --git a/src/render_helpers/offscreen.rs b/src/render_helpers/offscreen.rs
index 9005e80c..9f4857af 100644
--- a/src/render_helpers/offscreen.rs
+++ b/src/render_helpers/offscreen.rs
@@ -1,251 +1,116 @@
+use std::cell::RefCell;
+
+use anyhow::Context as _;
 use smithay::backend::allocator::Fourcc;
-use smithay::backend::renderer::element::solid::{SolidColorBuffer, SolidColorRenderElement};
 use smithay::backend::renderer::element::utils::{Relocate, RelocateRenderElement};
-use smithay::backend::renderer::element::{Element, Id, Kind, RenderElement, UnderlyingStorage};
-use smithay::backend::renderer::gles::{GlesError, GlesFrame, GlesRenderer};
-use smithay::backend::renderer::utils::{CommitCounter, DamageSet, OpaqueRegions};
-use smithay::utils::{Buffer, Physical, Rectangle, Scale, Transform};
-
-use super::primary_gpu_texture::PrimaryGpuTextureRenderElement;
-use super::render_to_texture;
-use super::renderer::AsGlesFrame;
-use super::texture::{TextureBuffer, TextureRenderElement};
-use crate::backend::tty::{TtyFrame, TtyRenderer, TtyRendererError};
-
-/// Renders elements into an off-screen buffer.
+use smithay::backend::renderer::element::RenderElement;
+use smithay::backend::renderer::gles::{GlesRenderer, GlesTexture};
+use smithay::backend::renderer::sync::SyncPoint;
+use smithay::backend::renderer::{Bind as _, Offscreen as _, Texture as _};
+use smithay::utils::{Logical, Point, Scale, Transform};
+
+use super::texture::TextureBuffer;
+use super::{encompassing_geo, render_elements};
+
+/// Buffer for offscreen rendering.
 #[derive(Debug)]
-pub struct OffscreenRenderElement {
-    // The texture, if rendering succeeded.
-    texture: Option<PrimaryGpuTextureRenderElement>,
-    // The fallback buffer in case the rendering fails.
-    fallback: SolidColorRenderElement,
+pub struct OffscreenBuffer {
+    /// The cached texture buffer.
+    ///
+    /// Lazily created when `render` is called. Recreated when necessary.
+    buffer: RefCell<Option<TextureBuffer<GlesTexture>>>,
 }
 
-impl OffscreenRenderElement {
-    pub fn new(
+impl OffscreenBuffer {
+    pub fn render(
+        &self,
         renderer: &mut GlesRenderer,
-        scale: i32,
+        scale: Scale<f64>,
         elements: &[impl RenderElement<GlesRenderer>],
-        result_alpha: f32,
-    ) -> Self {
-        let _span = tracy_client::span!("OffscreenRenderElement::new");
-
-        let geo = elements
-            .iter()
-            .map(|ele| ele.geometry(Scale::from(f64::from(scale))))
-            .reduce(|a, b| a.merge(b))
-            .unwrap_or_default();
-        let logical_size = geo.size.to_logical(scale);
-
-        let fallback_buffer = SolidColorBuffer::new(logical_size, [1., 0., 0., 1.]);
-        let fallback = SolidColorRenderElement::from_buffer(
-            &fallback_buffer,
-            geo.loc,
-            Scale::from(scale as f64),
-            result_alpha,
-            Kind::Unspecified,
-        );
+    ) -> anyhow::Result<(TextureBuffer<GlesTexture>, SyncPoint, Point<f64, Logical>)> {
+        let _span = tracy_client::span!("OffscreenBuffer::render");
 
+        let geo = encompassing_geo(scale, elements.iter());
         let elements = elements.iter().rev().map(|ele| {
-            RelocateRenderElement::from_element(ele, (-geo.loc.x, -geo.loc.y), Relocate::Relative)
+            RelocateRenderElement::from_element(ele, geo.loc.upscale(-1), Relocate::Relative)
         });
 
-        match render_to_texture(
-            renderer,
-            geo.size,
-            Scale::from(scale as f64),
-            Transform::Normal,
-            Fourcc::Abgr8888,
-            elements,
-        ) {
-            Ok((texture, _sync_point)) => {
-                let buffer = TextureBuffer::from_texture(
-                    renderer,
-                    texture,
-                    scale as f64,
-                    Transform::Normal,
-                    Vec::new(),
-                );
-                let element = TextureRenderElement::from_texture_buffer(
-                    buffer,
-                    geo.loc.to_f64().to_logical(scale as f64),
-                    result_alpha,
-                    None,
-                    None,
-                    Kind::Unspecified,
-                );
-                Self {
-                    texture: Some(PrimaryGpuTextureRenderElement(element)),
-                    fallback,
-                }
-            }
-            Err(err) => {
-                warn!("error off-screening elements: {err:?}");
-                Self {
-                    texture: None,
-                    fallback,
-                }
-            }
-        }
-    }
-}
+        let buffer_size = geo.size.to_logical(1).to_buffer(1, Transform::Normal);
+        let offset = geo.loc.to_f64().to_logical(scale);
 
-impl Element for OffscreenRenderElement {
-    fn id(&self) -> &Id {
-        if let Some(texture) = &self.texture {
-            texture.id()
-        } else {
-            self.fallback.id()
-        }
-    }
+        let mut buffer = self.buffer.borrow_mut();
 
-    fn current_commit(&self) -> CommitCounter {
-        if let Some(texture) = &self.texture {
-            texture.current_commit()
-        } else {
-            self.fallback.current_commit()
-        }
-    }
+        // Check if we need to create or recreate the texture.
+        let size_string;
+        let mut reason = "";
+        if let Some(buf) = buffer.as_mut() {
+            let old_size = buf.texture().size();
+            if old_size != buffer_size {
+                size_string = format!(
+                    "size changed from {} × {} to {} × {}",
+                    old_size.w, old_size.h, buffer_size.w, buffer_size.h
+                );
+                reason = &size_string;
 
-    fn geometry(&self, scale: Scale<f64>) -> Rectangle<i32, Physical> {
-        if let Some(texture) = &self.texture {
-            texture.geometry(scale)
-        } else {
-            self.fallback.geometry(scale)
-        }
-    }
+                *buffer = None;
+            } else if !buf.is_texture_reference_unique() {
+                reason = "not unique";
 
-    fn transform(&self) -> Transform {
-        if let Some(texture) = &self.texture {
-            texture.transform()
+                *buffer = None;
+            }
         } else {
-            self.fallback.transform()
+            reason = "first render";
         }
-    }
 
-    fn src(&self) -> Rectangle<f64, Buffer> {
-        if let Some(texture) = &self.texture {
-            texture.src()
+        let buffer = if let Some(buffer) = buffer.as_mut() {
+            buffer
         } else {
-            self.fallback.src()
-        }
-    }
+            trace!("creating new texture: {reason}");
+            let span = tracy_client::span!("creating offscreen buffer");
+            span.emit_text(reason);
 
-    fn damage_since(
-        &self,
-        scale: Scale<f64>,
-        commit: Option<CommitCounter>,
-    ) -> DamageSet<i32, Physical> {
-        if let Some(texture) = &self.texture {
-            texture.damage_since(scale, commit)
-        } else {
-            self.fallback.damage_since(scale, commit)
-        }
-    }
+            let texture: GlesTexture = renderer
+                .create_buffer(Fourcc::Abgr8888, buffer_size)
+                .context("error creating texture")?;
 
-    fn opaque_regions(&self, scale: Scale<f64>) -> OpaqueRegions<i32, Physical> {
-        if let Some(texture) = &self.texture {
-            texture.opaque_regions(scale)
-        } else {
-            self.fallback.opaque_regions(scale)
-        }
-    }
+            buffer.insert(TextureBuffer::from_texture(
+                renderer,
+                texture,
+                scale,
+                Transform::Normal,
+                Vec::new(),
+            ))
+        };
 
-    fn alpha(&self) -> f32 {
-        if let Some(texture) = &self.texture {
-            texture.alpha()
-        } else {
-            self.fallback.alpha()
-        }
-    }
+        // Update the texture scale.
+        buffer.set_texture_scale(scale);
 
-    fn kind(&self) -> Kind {
-        if let Some(texture) = &self.texture {
-            texture.kind()
-        } else {
-            self.fallback.kind()
-        }
-    }
-}
+        // Increment the commit counter since we're rendering new contents to the buffer.
+        buffer.increment_commit_counter();
 
-impl RenderElement<GlesRenderer> for OffscreenRenderElement {
-    fn draw(
-        &self,
-        frame: &mut GlesFrame<'_, '_>,
-        src: Rectangle<f64, Buffer>,
-        dst: Rectangle<i32, Physical>,
-        damage: &[Rectangle<i32, Physical>],
-        opaque_regions: &[Rectangle<i32, Physical>],
-    ) -> Result<(), GlesError> {
-        let gles_frame = frame.as_gles_frame();
-        if let Some(texture) = &self.texture {
-            RenderElement::<GlesRenderer>::draw(
-                texture,
-                gles_frame,
-                src,
-                dst,
-                damage,
-                opaque_regions,
-            )?;
-        } else {
-            RenderElement::<GlesRenderer>::draw(
-                &self.fallback,
-                gles_frame,
-                src,
-                dst,
-                damage,
-                opaque_regions,
-            )?;
-        }
-        Ok(())
-    }
+        // Render to the buffer.
+        let mut texture = buffer.texture().clone();
+        let mut target = renderer
+            .bind(&mut texture)
+            .context("error binding texture")?;
 
-    fn underlying_storage(&self, renderer: &mut GlesRenderer) -> Option<UnderlyingStorage> {
-        if let Some(texture) = &self.texture {
-            texture.underlying_storage(renderer)
-        } else {
-            self.fallback.underlying_storage(renderer)
-        }
-    }
-}
+        let sync_point = render_elements(
+            renderer,
+            &mut target,
+            geo.size,
+            scale,
+            Transform::Normal,
+            elements,
+        )?;
 
-impl<'render> RenderElement<TtyRenderer<'render>> for OffscreenRenderElement {
-    fn draw(
-        &self,
-        frame: &mut TtyFrame<'_, '_, '_>,
-        src: Rectangle<f64, Buffer>,
-        dst: Rectangle<i32, Physical>,
-        damage: &[Rectangle<i32, Physical>],
-        opaque_regions: &[Rectangle<i32, Physical>],
-    ) -> Result<(), TtyRendererError<'render>> {
-        let gles_frame = frame.as_gles_frame();
-        if let Some(texture) = &self.texture {
-            RenderElement::<GlesRenderer>::draw(
-                texture,
-                gles_frame,
-                src,
-                dst,
-                damage,
-                opaque_regions,
-            )?;
-        } else {
-            RenderElement::<GlesRenderer>::draw(
-                &self.fallback,
-                gles_frame,
-                src,
-                dst,
-                damage,
-                opaque_regions,
-            )?;
-        }
-        Ok(())
+        Ok((buffer.clone(), sync_point, offset))
     }
+}
 
-    fn underlying_storage(&self, renderer: &mut TtyRenderer<'render>) -> Option<UnderlyingStorage> {
-        if let Some(texture) = &self.texture {
-            texture.underlying_storage(renderer)
-        } else {
-            self.fallback.underlying_storage(renderer)
+impl Default for OffscreenBuffer {
+    fn default() -> Self {
+        OffscreenBuffer {
+            buffer: RefCell::new(None),
         }
     }
 }
diff --git a/src/render_helpers/texture.rs b/src/render_helpers/texture.rs
index a5d38a6f..e88ac0e3 100644
--- a/src/render_helpers/texture.rs
+++ b/src/render_helpers/texture.rs
@@ -1,5 +1,6 @@
 use smithay::backend::allocator::Fourcc;
 use smithay::backend::renderer::element::{Element, Id, Kind, RenderElement, UnderlyingStorage};
+use smithay::backend::renderer::gles::GlesTexture;
 use smithay::backend::renderer::utils::{CommitCounter, OpaqueRegions};
 use smithay::backend::renderer::{Frame as _, ImportMem, Renderer, Texture};
 use smithay::utils::{Buffer, Logical, Physical, Point, Rectangle, Scale, Size, Transform};
@@ -104,6 +105,10 @@ impl<T> TextureBuffer<T> {
     pub fn set_texture_transform(&mut self, transform: Transform) {
         self.transform = transform;
     }
+
+    pub fn increment_commit_counter(&mut self) {
+        self.commit_counter.increment();
+    }
 }
 
 impl<T: Texture> TextureBuffer<T> {
@@ -115,6 +120,12 @@ impl<T: Texture> TextureBuffer<T> {
     }
 }
 
+impl TextureBuffer<GlesTexture> {
+    pub fn is_texture_reference_unique(&mut self) -> bool {
+        self.texture.is_unique_reference()
+    }
+}
+
 impl<T> TextureRenderElement<T> {
     pub fn from_texture_buffer(
         buffer: TextureBuffer<T>,