Optimize order rendering and border drawing (#3759)

Antonio Scandurra created

This fixes the slowdowns we were observing when opening the saved
assistant conversations.

Release Notes:

- N/A

Change summary

Cargo.lock                   |  12 ---
crates/gpui2/Cargo.toml      |   1 
crates/gpui2/src/geometry.rs |  21 ++++++
crates/gpui2/src/scene.rs    | 126 ++++++-------------------------------
crates/gpui2/src/style.rs    |  60 ++++++++++++++++-
crates/gpui2/src/window.rs   |   1 
6 files changed, 101 insertions(+), 120 deletions(-)

Detailed changes

Cargo.lock 🔗

@@ -4060,7 +4060,6 @@ dependencies = [
  "parking",
  "parking_lot 0.11.2",
  "pathfinder_geometry",
- "plane-split",
  "png",
  "postage",
  "rand 0.8.5",
@@ -6656,17 +6655,6 @@ version = "0.3.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "26072860ba924cbfa98ea39c8c19b4dd6a4a25423dbdf219c1eca91aa0cf6964"
 
-[[package]]
-name = "plane-split"
-version = "0.18.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8c1f7d82649829ecdef8e258790b0587acf0a8403f0ce963473d8e918acc1643"
-dependencies = [
- "euclid",
- "log",
- "smallvec",
-]
-
 [[package]]
 name = "plist"
 version = "1.5.0"

crates/gpui2/Cargo.toml 🔗

@@ -56,7 +56,6 @@ uuid = { version = "1.1.2", features = ["v4"] }
 waker-fn = "1.1.0"
 slotmap = "1.0.6"
 schemars.workspace = true
-plane-split = "0.18.0"
 bitflags = "2.4.0"
 
 [dev-dependencies]

crates/gpui2/src/geometry.rs 🔗

@@ -1590,6 +1590,15 @@ impl Edges<Pixels> {
             left: self.left.scale(factor),
         }
     }
+
+    /// Returns the maximum value of any edge.
+    ///
+    /// # Returns
+    ///
+    /// The maximum `Pixels` value among all four edges.
+    pub fn max(&self) -> Pixels {
+        self.top.max(self.right).max(self.bottom).max(self.left)
+    }
 }
 
 impl Into<Edges<Pixels>> for f32 {
@@ -1740,6 +1749,18 @@ impl Corners<Pixels> {
             bottom_left: self.bottom_left.scale(factor),
         }
     }
+
+    /// Returns the maximum value of any corner.
+    ///
+    /// # Returns
+    ///
+    /// The maximum `Pixels` value among all four corners.
+    pub fn max(&self) -> Pixels {
+        self.top_left
+            .max(self.top_right)
+            .max(self.bottom_right)
+            .max(self.bottom_left)
+    }
 }
 
 impl<T: Clone + Default + Debug> Corners<T> {

crates/gpui2/src/scene.rs 🔗

@@ -3,8 +3,6 @@ use crate::{
     ScaledPixels, StackingOrder,
 };
 use collections::BTreeMap;
-use etagere::euclid::{Point3D, Vector3D};
-use plane_split::{BspSplitter, Polygon as BspPolygon};
 use std::{fmt::Debug, iter::Peekable, mem, slice};
 
 // Exported to metal
@@ -19,7 +17,6 @@ pub type DrawOrder = u32;
 pub(crate) struct SceneBuilder {
     last_order: Option<(StackingOrder, LayerId)>,
     layers_by_order: BTreeMap<StackingOrder, LayerId>,
-    splitter: BspSplitter<(PrimitiveKind, usize)>,
     shadows: Vec<Shadow>,
     quads: Vec<Quad>,
     paths: Vec<Path<ScaledPixels>>,
@@ -34,7 +31,6 @@ impl Default for SceneBuilder {
         SceneBuilder {
             last_order: None,
             layers_by_order: BTreeMap::new(),
-            splitter: BspSplitter::new(),
             shadows: Vec::new(),
             quads: Vec::new(),
             paths: Vec::new(),
@@ -48,103 +44,47 @@ impl Default for SceneBuilder {
 
 impl SceneBuilder {
     pub fn build(&mut self) -> Scene {
-        // Map each layer id to a float between 0. and 1., with 1. closer to the viewer.
-        let mut layer_z_values = vec![0.; self.layers_by_order.len()];
+        let mut orders = vec![0; self.layers_by_order.len()];
         for (ix, layer_id) in self.layers_by_order.values().enumerate() {
-            layer_z_values[*layer_id as usize] = ix as f32 / self.layers_by_order.len() as f32;
+            orders[*layer_id as usize] = ix as u32;
         }
         self.layers_by_order.clear();
         self.last_order = None;
 
-        // Add all primitives to the BSP splitter to determine draw order
-        self.splitter.reset();
-
-        for (ix, shadow) in self.shadows.iter().enumerate() {
-            let z = layer_z_values[shadow.order as LayerId as usize];
-            self.splitter
-                .add(shadow.bounds.to_bsp_polygon(z, (PrimitiveKind::Shadow, ix)));
-        }
-
-        for (ix, quad) in self.quads.iter().enumerate() {
-            let z = layer_z_values[quad.order as LayerId as usize];
-            self.splitter
-                .add(quad.bounds.to_bsp_polygon(z, (PrimitiveKind::Quad, ix)));
+        for shadow in &mut self.shadows {
+            shadow.order = orders[shadow.order as usize];
         }
+        self.shadows.sort_by_key(|shadow| shadow.order);
 
-        for (ix, path) in self.paths.iter().enumerate() {
-            let z = layer_z_values[path.order as LayerId as usize];
-            self.splitter
-                .add(path.bounds.to_bsp_polygon(z, (PrimitiveKind::Path, ix)));
+        for quad in &mut self.quads {
+            quad.order = orders[quad.order as usize];
         }
+        self.quads.sort_by_key(|quad| quad.order);
 
-        for (ix, underline) in self.underlines.iter().enumerate() {
-            let z = layer_z_values[underline.order as LayerId as usize];
-            self.splitter.add(
-                underline
-                    .bounds
-                    .to_bsp_polygon(z, (PrimitiveKind::Underline, ix)),
-            );
+        for path in &mut self.paths {
+            path.order = orders[path.order as usize];
         }
+        self.paths.sort_by_key(|path| path.order);
 
-        for (ix, monochrome_sprite) in self.monochrome_sprites.iter().enumerate() {
-            let z = layer_z_values[monochrome_sprite.order as LayerId as usize];
-            self.splitter.add(
-                monochrome_sprite
-                    .bounds
-                    .to_bsp_polygon(z, (PrimitiveKind::MonochromeSprite, ix)),
-            );
+        for underline in &mut self.underlines {
+            underline.order = orders[underline.order as usize];
         }
+        self.underlines.sort_by_key(|underline| underline.order);
 
-        for (ix, polychrome_sprite) in self.polychrome_sprites.iter().enumerate() {
-            let z = layer_z_values[polychrome_sprite.order as LayerId as usize];
-            self.splitter.add(
-                polychrome_sprite
-                    .bounds
-                    .to_bsp_polygon(z, (PrimitiveKind::PolychromeSprite, ix)),
-            );
+        for monochrome_sprite in &mut self.monochrome_sprites {
+            monochrome_sprite.order = orders[monochrome_sprite.order as usize];
         }
+        self.monochrome_sprites.sort_by_key(|sprite| sprite.order);
 
-        for (ix, surface) in self.surfaces.iter().enumerate() {
-            let z = layer_z_values[surface.order as LayerId as usize];
-            self.splitter.add(
-                surface
-                    .bounds
-                    .to_bsp_polygon(z, (PrimitiveKind::Surface, ix)),
-            );
+        for polychrome_sprite in &mut self.polychrome_sprites {
+            polychrome_sprite.order = orders[polychrome_sprite.order as usize];
         }
+        self.polychrome_sprites.sort_by_key(|sprite| sprite.order);
 
-        // Sort all polygons, then reassign the order field of each primitive to `draw_order`
-        // We need primitives to be repr(C), hence the weird reuse of the order field for two different types.
-        for (draw_order, polygon) in self
-            .splitter
-            .sort(Vector3D::new(0., 0., 1.))
-            .iter()
-            .enumerate()
-        {
-            match polygon.anchor {
-                (PrimitiveKind::Shadow, ix) => self.shadows[ix].order = draw_order as DrawOrder,
-                (PrimitiveKind::Quad, ix) => self.quads[ix].order = draw_order as DrawOrder,
-                (PrimitiveKind::Path, ix) => self.paths[ix].order = draw_order as DrawOrder,
-                (PrimitiveKind::Underline, ix) => {
-                    self.underlines[ix].order = draw_order as DrawOrder
-                }
-                (PrimitiveKind::MonochromeSprite, ix) => {
-                    self.monochrome_sprites[ix].order = draw_order as DrawOrder
-                }
-                (PrimitiveKind::PolychromeSprite, ix) => {
-                    self.polychrome_sprites[ix].order = draw_order as DrawOrder
-                }
-                (PrimitiveKind::Surface, ix) => self.surfaces[ix].order = draw_order as DrawOrder,
-            }
+        for surface in &mut self.surfaces {
+            surface.order = orders[surface.order as usize];
         }
-
-        self.shadows.sort_unstable();
-        self.quads.sort_unstable();
-        self.paths.sort_unstable();
-        self.underlines.sort_unstable();
-        self.monochrome_sprites.sort_unstable();
-        self.polychrome_sprites.sort_unstable();
-        self.surfaces.sort_unstable();
+        self.surfaces.sort_by_key(|surface| surface.order);
 
         Scene {
             shadows: mem::take(&mut self.shadows),
@@ -845,23 +785,3 @@ impl PathVertex<Pixels> {
 
 #[derive(Copy, Clone, Debug)]
 pub struct AtlasId(pub(crate) usize);
-
-impl Bounds<ScaledPixels> {
-    fn to_bsp_polygon<A: Copy>(&self, z: f32, anchor: A) -> BspPolygon<A> {
-        let upper_left = self.origin;
-        let upper_right = self.upper_right();
-        let lower_right = self.lower_right();
-        let lower_left = self.lower_left();
-
-        BspPolygon::from_points(
-            [
-                Point3D::new(upper_left.x.into(), upper_left.y.into(), z as f64),
-                Point3D::new(upper_right.x.into(), upper_right.y.into(), z as f64),
-                Point3D::new(lower_right.x.into(), lower_right.y.into(), z as f64),
-                Point3D::new(lower_left.x.into(), lower_left.y.into(), z as f64),
-            ],
-            anchor,
-        )
-        .expect("Polygon should not be empty")
-    }
-}

crates/gpui2/src/style.rs 🔗

@@ -402,13 +402,65 @@ impl Style {
 
         if self.is_border_visible() {
             cx.with_z_index(3, |cx| {
-                cx.paint_quad(quad(
+                let corner_radii = self.corner_radii.to_pixels(bounds.size, rem_size);
+                let border_widths = self.border_widths.to_pixels(rem_size);
+                let max_border_width = border_widths.max();
+                let max_corner_radius = corner_radii.max();
+
+                let top_bounds = Bounds::from_corners(
+                    bounds.origin,
+                    bounds.upper_right()
+                        + point(Pixels::ZERO, max_border_width.max(max_corner_radius)),
+                );
+                let bottom_bounds = Bounds::from_corners(
+                    bounds.lower_left()
+                        - point(Pixels::ZERO, max_border_width.max(max_corner_radius)),
+                    bounds.lower_right(),
+                );
+                let left_bounds = Bounds::from_corners(
+                    top_bounds.lower_left(),
+                    bottom_bounds.origin + point(max_border_width, Pixels::ZERO),
+                );
+                let right_bounds = Bounds::from_corners(
+                    top_bounds.lower_right() - point(max_border_width, Pixels::ZERO),
+                    bottom_bounds.upper_right(),
+                );
+
+                let quad = quad(
                     bounds,
-                    self.corner_radii.to_pixels(bounds.size, rem_size),
+                    corner_radii,
                     Hsla::transparent_black(),
-                    self.border_widths.to_pixels(rem_size),
+                    border_widths,
                     self.border_color.unwrap_or_default(),
-                ));
+                );
+
+                cx.with_content_mask(Some(ContentMask { bounds: top_bounds }), |cx| {
+                    cx.paint_quad(quad.clone());
+                });
+                cx.with_content_mask(
+                    Some(ContentMask {
+                        bounds: right_bounds,
+                    }),
+                    |cx| {
+                        cx.paint_quad(quad.clone());
+                    },
+                );
+                cx.with_content_mask(
+                    Some(ContentMask {
+                        bounds: bottom_bounds,
+                    }),
+                    |cx| {
+                        cx.paint_quad(quad.clone());
+                    },
+                );
+                cx.with_content_mask(
+                    Some(ContentMask {
+                        bounds: left_bounds,
+                    }),
+                    |cx| {
+                        cx.paint_quad(quad);
+                    },
+                );
             });
         }
 

crates/gpui2/src/window.rs 🔗

@@ -3074,6 +3074,7 @@ impl From<(&'static str, u64)> for ElementId {
 }
 
 /// A rectangle, to be rendered on the screen by GPUI at the given position and size.
+#[derive(Clone)]
 pub struct PaintQuad {
     bounds: Bounds<Pixels>,
     corner_radii: Corners<Pixels>,