Fix tessellation of Shape::Vec of heterogenous TextureId:s (#1445)

Closes https://github.com/emilk/egui/issues/1443

CHANGELOG.md

@@ -18,7 +18,6 @@ NOTE: [`epaint`](epaint/CHANGELOG.md), [`eframe`](eframe/CHANGELOG.md), [`egui_w
 * `ClippedMesh` has been replaced with `ClippedPrimitive` ([#1351](https://github.com/emilk/egui/pull/1351)).
 * Renamed `Frame::margin` to `Frame::inner_margin`.
 * Renamed `AlphaImage` to `FontImage` to discourage any other use for it ([#1412](https://github.com/emilk/egui/pull/1412)).
-* `dark-light` (dark mode detection) is now an opt-in feature for `eframe` and `egui_glow` ([#1437](https://github.com/emilk/egui/pull/1437)).
 
 ### Fixed 🐛
 * Fixed ComboBoxes always being rendered left-aligned ([#1304](https://github.com/emilk/egui/pull/1304)).

eframe/CHANGELOG.md

@@ -19,6 +19,7 @@ NOTE: [`egui_web`](../egui_web/CHANGELOG.md), [`egui-winit`](../egui-winit/CHANG
   * Changed `App::update` to take `&mut Frame` instead of `&Frame`.
   * `Frame` is no longer `Clone` or `Sync`.
 * Add `glow` (OpenGL) context to `Frame` ([#1425](https://github.com/emilk/egui/pull/1425)).
+* `dark-light` (dark mode detection) is now an opt-in feature ([#1437](https://github.com/emilk/egui/pull/1437)).
 * Fixed potential scale bug when DPI scaling changes (e.g. when dragging a  window between different displays) ([#1441](https://github.com/emilk/egui/pull/1441)).
 
 

egui_demo_lib/benches/benchmark.rs

@@ -123,13 +123,14 @@ pub fn criterion_benchmark(c: &mut Criterion) {
         });
 
         let galley = fonts.layout(LOREM_IPSUM_LONG.to_owned(), font_id, color, wrap_width);
-        let mut tessellator = egui::epaint::Tessellator::new(1.0, Default::default());
+        let font_image_size = fonts.font_image_size();
+        let mut tessellator =
+            egui::epaint::Tessellator::new(1.0, Default::default(), font_image_size);
         let mut mesh = egui::epaint::Mesh::default();
         let text_shape = TextShape::new(egui::Pos2::ZERO, galley);
-        let font_image_size = fonts.font_image_size();
         c.bench_function("tessellate_text", |b| {
             b.iter(|| {
-                tessellator.tessellate_text(font_image_size, &text_shape, &mut mesh);
+                tessellator.tessellate_text(&text_shape, &mut mesh);
                 mesh.clear();
             });
         });

egui_glow/CHANGELOG.md

@@ -5,6 +5,7 @@ All notable changes to the `egui_glow` integration will be noted in this file.
 ## Unreleased
 * Improved logging on rendering failures.
 * Add new `NativeOptions`: `vsync`, `multisampling`, `depth_buffer`, `stencil_buffer`.
+* `dark-light` (dark mode detection) is now an opt-in feature ([#1437](https://github.com/emilk/egui/pull/1437)).
 * Fixed potential scale bug when DPI scaling changes (e.g. when dragging a  window between different displays) ([#1441](https://github.com/emilk/egui/pull/1441)).
 
 

epaint/CHANGELOG.md

@@ -9,6 +9,7 @@ All notable changes to the epaint crate will be documented in this file.
 * Renamed `TessellationOptions::anti_alias` to `feathering` ([#1408](https://github.com/emilk/egui/pull/1408)).
 * Renamed `AlphaImage` to `FontImage` to discourage any other use for it ([#1412](https://github.com/emilk/egui/pull/1412)).
 * Dark text is darker and more readable on bright backgrounds ([#1412](https://github.com/emilk/egui/pull/1412)).
+* Fix panic when tessellating a [`Shape::Vec`] containing meshes with differing `TextureId`:s ([#1445](https://github.com/emilk/egui/pull/1445)).
 
 
 ## 0.17.0 - 2022-02-22

epaint/src/shadow.rs

@@ -64,6 +64,7 @@ impl Shadow {
         use crate::tessellator::*;
         let rect = RectShape::filled(rect.expand(half_ext), ext_rounding, color);
         let pixels_per_point = 1.0; // doesn't matter here
+        let font_tex_size = [1; 2]; // unused size we are not tessellating text.
         let mut tessellator = Tessellator::new(
             pixels_per_point,
             TessellationOptions {
@@ -71,6 +72,7 @@ impl Shadow {
                 feathering_size_in_pixels: extrusion * pixels_per_point,
                 ..Default::default()
             },
+            font_tex_size,
         );
         let mut mesh = Mesh::default();
         tessellator.tessellate_rect(&rect, &mut mesh);

epaint/src/tessellator.rs

@@ -651,6 +651,7 @@ fn mul_color(color: Color32, factor: f32) -> Color32 {
 pub struct Tessellator {
     pixels_per_point: f32,
     options: TessellationOptions,
+    font_tex_size: [usize; 2],
     /// size of feathering in points. normally the size of a physical pixel. 0.0 if disabled
     feathering: f32,
     /// Only used for culling
@@ -661,7 +662,13 @@ pub struct Tessellator {
 
 impl Tessellator {
     /// Create a new [`Tessellator`].
-    pub fn new(pixels_per_point: f32, options: TessellationOptions) -> Self {
+    ///
+    /// * `font_tex_size`: size of the font texture. Required to normalize glyph uv rectangles when tessellating text.
+    pub fn new(
+        pixels_per_point: f32,
+        options: TessellationOptions,
+        font_tex_size: [usize; 2],
+    ) -> Self {
         let feathering = if options.feathering {
             let pixel_size = 1.0 / pixels_per_point;
             options.feathering_size_in_pixels * pixel_size
@@ -671,6 +678,7 @@ impl Tessellator {
         Self {
             pixels_per_point,
             options,
+            font_tex_size,
             feathering,
             clip_rect: Rect::EVERYTHING,
             scratchpad_points: Default::default(),
@@ -692,17 +700,74 @@ impl Tessellator {
         }
     }
 
+    /// Tessellate a clipped shape into a list of primitives.
+    pub fn tessellate_clipped_shape(
+        &mut self,
+        clipped_shape: ClippedShape,
+        out_primitives: &mut Vec<ClippedPrimitive>,
+    ) {
+        let ClippedShape(new_clip_rect, new_shape) = clipped_shape;
+
+        if !new_clip_rect.is_positive() {
+            return; // skip empty clip rectangles
+        }
+
+        if let Shape::Vec(shapes) = new_shape {
+            for shape in shapes {
+                self.tessellate_clipped_shape(ClippedShape(new_clip_rect, shape), out_primitives);
+            }
+            return;
+        }
+
+        if let Shape::Callback(callback) = new_shape {
+            out_primitives.push(ClippedPrimitive {
+                clip_rect: new_clip_rect,
+                primitive: Primitive::Callback(callback),
+            });
+            return;
+        }
+
+        let start_new_mesh = match out_primitives.last() {
+            None => true,
+            Some(output_clipped_primitive) => {
+                output_clipped_primitive.clip_rect != new_clip_rect
+                    || if let Primitive::Mesh(output_mesh) = &output_clipped_primitive.primitive {
+                        output_mesh.texture_id != new_shape.texture_id()
+                    } else {
+                        true
+                    }
+            }
+        };
+
+        if start_new_mesh {
+            out_primitives.push(ClippedPrimitive {
+                clip_rect: new_clip_rect,
+                primitive: Primitive::Mesh(Mesh::default()),
+            });
+        }
+
+        let out = out_primitives.last_mut().unwrap();
+
+        if let Primitive::Mesh(out_mesh) = &mut out.primitive {
+            self.clip_rect = new_clip_rect;
+            self.tessellate_shape(new_shape, out_mesh);
+        } else {
+            unreachable!();
+        }
+    }
+
     /// Tessellate a single [`Shape`] into a [`Mesh`].
     ///
-    /// * `tex_size`: size of the font texture (required to normalize glyph uv rectangles).
+    /// This call can panic the given shape is of [`Shape::Vec`] or [`Shape::Callback`].
+    /// For that, use [`Self::tessellate_clipped_shape`] instead.
     /// * `shape`: the shape to tessellate.
     /// * `out`: triangles are appended to this.
-    pub fn tessellate_shape(&mut self, tex_size: [usize; 2], shape: Shape, out: &mut Mesh) {
+    pub fn tessellate_shape(&mut self, shape: Shape, out: &mut Mesh) {
         match shape {
             Shape::Noop => {}
             Shape::Vec(vec) => {
                 for shape in vec {
-                    self.tessellate_shape(tex_size, shape, out);
+                    self.tessellate_shape(shape, out);
                 }
             }
             Shape::Circle(circle) => {
@@ -736,7 +801,7 @@ impl Tessellator {
                         out,
                     );
                 }
-                self.tessellate_text(tex_size, &text_shape, out);
+                self.tessellate_text(&text_shape, out);
             }
             Shape::QuadraticBezier(quadratic_shape) => {
                 self.tessellate_quadratic_bezier(quadratic_shape, out);
@@ -902,16 +967,9 @@ impl Tessellator {
     }
 
     /// Tessellate a single [`TextShape`] into a [`Mesh`].
-    ///
-    /// * `tex_size`: size of the font texture (required to normalize glyph uv rectangles).
     /// * `text_shape`: the text to tessellate.
     /// * `out`: triangles are appended to this.
-    pub fn tessellate_text(
+    pub fn tessellate_text(&mut self, text_shape: &TextShape, out: &mut Mesh) {
-        &mut self,
-        tex_size: [usize; 2],
-        text_shape: &TextShape,
-        out: &mut Mesh,
-    ) {
         let TextShape {
             pos: galley_pos,
             galley,
@@ -934,7 +992,10 @@ impl Tessellator {
             self.round_to_pixel(galley_pos.y),
         );
 
-        let uv_normalizer = vec2(1.0 / tex_size[0] as f32, 1.0 / tex_size[1] as f32);
+        let uv_normalizer = vec2(
+            1.0 / self.font_tex_size[0] as f32,
+            1.0 / self.font_tex_size[1] as f32,
+        );
 
         let rotator = Rot2::from_angle(*angle);
 
@@ -1099,7 +1160,7 @@ impl Tessellator {
 /// * `pixels_per_point`: number of physical pixels to each logical point
 /// * `options`: tessellation quality
 /// * `shapes`: what to tessellate
-/// * `tex_size`: size of the font texture (required to normalize glyph uv rectangles)
+/// * `font_tex_size`: size of the font texture (required to normalize glyph uv rectangles)
 ///
 /// The implementation uses a [`Tessellator`].
 ///
@@ -1109,56 +1170,18 @@ pub fn tessellate_shapes(
     pixels_per_point: f32,
     options: TessellationOptions,
     shapes: Vec<ClippedShape>,
-    tex_size: [usize; 2],
+    font_tex_size: [usize; 2],
 ) -> Vec<ClippedPrimitive> {
-    let mut tessellator = Tessellator::new(pixels_per_point, options);
+    let mut tessellator = Tessellator::new(pixels_per_point, options, font_tex_size);
 
     let mut clipped_primitives: Vec<ClippedPrimitive> = Vec::default();
 
-    for ClippedShape(new_clip_rect, new_shape) in shapes {
+    for clipped_shape in shapes {
-        if !new_clip_rect.is_positive() {
+        tessellator.tessellate_clipped_shape(clipped_shape, &mut clipped_primitives);
-            continue; // skip empty clip rectangles
-        }
-
-        if let Shape::Callback(callback) = new_shape {
-            clipped_primitives.push(ClippedPrimitive {
-                clip_rect: new_clip_rect,
-                primitive: Primitive::Callback(callback),
-            });
-        } else {
-            let start_new_mesh = match clipped_primitives.last() {
-                None => true,
-                Some(output_clipped_primitive) => {
-                    output_clipped_primitive.clip_rect != new_clip_rect
-                        || if let Primitive::Mesh(output_mesh) = &output_clipped_primitive.primitive
-                        {
-                            output_mesh.texture_id != new_shape.texture_id()
-                        } else {
-                            true
-                        }
-                }
-            };
-
-            if start_new_mesh {
-                clipped_primitives.push(ClippedPrimitive {
-                    clip_rect: new_clip_rect,
-                    primitive: Primitive::Mesh(Mesh::default()),
-                });
-            }
-
-            let out = clipped_primitives.last_mut().unwrap();
-
-            if let Primitive::Mesh(out_mesh) = &mut out.primitive {
-                tessellator.clip_rect = new_clip_rect;
-                tessellator.tessellate_shape(tex_size, new_shape, out_mesh);
-            } else {
-                unreachable!();
-            }
-        }
     }
 
     if options.debug_paint_clip_rects {
-        clipped_primitives = add_clip_rects(&mut tessellator, tex_size, clipped_primitives);
+        clipped_primitives = add_clip_rects(&mut tessellator, clipped_primitives);
     }
 
     if options.debug_ignore_clip_rects {
@@ -1178,7 +1201,6 @@ pub fn tessellate_shapes(
 
 fn add_clip_rects(
     tessellator: &mut Tessellator,
-    tex_size: [usize; 2],
     clipped_primitives: Vec<ClippedPrimitive>,
 ) -> Vec<ClippedPrimitive> {
     tessellator.clip_rect = Rect::EVERYTHING;
@@ -1189,7 +1211,6 @@ fn add_clip_rects(
         .flat_map(|clipped_primitive| {
             let mut clip_rect_mesh = Mesh::default();
             tessellator.tessellate_shape(
-                tex_size,
                 Shape::rect_stroke(clipped_primitive.clip_rect, 0.0, stroke),
                 &mut clip_rect_mesh,
             );
@@ -1204,3 +1225,27 @@ fn add_clip_rects(
         })
         .collect()
 }
+
+#[test]
+fn test_tessellator() {
+    use crate::*;
+
+    let mut shapes = Vec::with_capacity(2);
+
+    let rect = Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0));
+    let uv = Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0));
+
+    let mut mesh = Mesh::with_texture(TextureId::Managed(1));
+    mesh.add_rect_with_uv(rect, uv, Color32::WHITE);
+    shapes.push(Shape::mesh(mesh));
+
+    let mut mesh = Mesh::with_texture(TextureId::Managed(2));
+    mesh.add_rect_with_uv(rect, uv, Color32::WHITE);
+    shapes.push(Shape::mesh(mesh));
+
+    let shape = Shape::Vec(shapes);
+    let clipped_shapes = vec![ClippedShape(rect, shape)];
+
+    let primitives = tessellate_shapes(1.0, Default::default(), clipped_shapes, [100, 100]);
+    assert_eq!(primitives.len(), 2);
+}