Remove viewport_id from tessellate and added tessellate_for

crates/eframe/src/native/run.rs

@@ -1204,7 +1204,7 @@ mod glow_integration {
 
             let screen_size_in_pixels: [u32; 2] = win.inner_size().into();
 
-            let clipped_primitives = egui_ctx.tessellate(output.shapes, id_pair.this);
+            let clipped_primitives = egui_ctx.tessellate(output.shapes);
 
             let mut glutin = glutin.borrow_mut();
             let mut painter = painter.borrow_mut();
@@ -1517,10 +1517,7 @@ mod glow_integration {
 
                 let clipped_primitives = {
                     crate::profile_scope!("tessellate");
-                    integration
-                        .borrow()
-                        .egui_ctx
-                        .tessellate(shapes, viewport_id)
+                    integration.borrow().egui_ctx.tessellate(shapes)
                 };
                 {
                     let mut glutin = glutin.borrow_mut();
@@ -2339,7 +2336,7 @@ mod wgpu_integration {
             }
 
             let pixels_per_point = egui_ctx.input_for(id_pair.this, |i| i.pixels_per_point());
-            let clipped_primitives = egui_ctx.tessellate(output.shapes, id_pair.this);
+            let clipped_primitives = egui_ctx.tessellate(output.shapes);
             painter.paint_and_update_textures(
                 id_pair.this,
                 pixels_per_point,
@@ -2508,10 +2505,7 @@ mod wgpu_integration {
 
                 let clipped_primitives = {
                     crate::profile_scope!("tessellate");
-                    integration
-                        .borrow()
-                        .egui_ctx
-                        .tessellate(shapes, viewport_id)
+                    integration.borrow().egui_ctx.tessellate(shapes)
                 };
 
                 let integration = &mut *integration.borrow_mut();

crates/egui/src/context.rs

@@ -162,6 +162,9 @@ struct ContextImpl {
     /// How deeply nested are we?
     viewport_stack: Vec<ViewportIdPair>,
 
+    /// What is the last viewport rendered?
+    last: ViewportId,
+
     // The output of a frame:
     graphics: ViewportIdMap<GraphicLayers>,
     output: ViewportIdMap<PlatformOutput>,
@@ -1540,6 +1543,8 @@ impl Context {
 
         let mut viewports = Vec::new();
         self.write(|ctx| {
+            ctx.last = viewport_id;
+
             ctx.viewports.retain(|_, viewport| {
                 let was_used = viewport.used;
 
@@ -1622,10 +1627,18 @@ impl Context {
         })
     }
 
+    /// Tessellate the given shapes into triangle meshes.
+    ///
+    /// Will use the last viewport id
+    pub fn tessellate(&self, shapes: Vec<ClippedShape>) -> Vec<ClippedPrimitive> {
+        let last = self.read(|ctx| ctx.last);
+        self.tessellate_for(shapes, last)
+    }
+
     /// Tessellate the given shapes into triangle meshes.
     ///
     /// The `viewport_id` is used to get the correct `pixels_per_point`.
-    pub fn tessellate(
+    pub fn tessellate_for(
         &self,
         shapes: Vec<ClippedShape>,
         viewport_id: ViewportId,

crates/egui_demo_lib/benches/benchmark.rs

@@ -1,6 +1,6 @@
 use criterion::{criterion_group, criterion_main, Criterion};
 
-use egui::{epaint::TextShape, ViewportId};
+use egui::epaint::TextShape;
 use egui_demo_lib::LOREM_IPSUM_LONG;
 
 pub fn criterion_benchmark(c: &mut Criterion) {
@@ -16,7 +16,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
                 let full_output = ctx.run(RawInput::default(), |ctx| {
                     demo_windows.ui(ctx);
                 });
-                ctx.tessellate(full_output.shapes, ViewportId::ROOT)
+                ctx.tessellate(full_output.shapes)
             });
         });
 
@@ -32,7 +32,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
             demo_windows.ui(ctx);
         });
         c.bench_function("demo_only_tessellate", |b| {
-            b.iter(|| ctx.tessellate(full_output.shapes.clone(), ViewportId::ROOT));
+            b.iter(|| ctx.tessellate(full_output.shapes.clone()));
         });
     }
 

crates/egui_demo_lib/src/lib.rs

@@ -18,8 +18,6 @@ pub mod easy_mark;
 
 pub use color_test::ColorTest;
 pub use demo::DemoWindows;
-#[cfg(test)]
-use egui::ViewportId;
 
 /// View some Rust code with syntax highlighting and selection.
 pub(crate) fn rust_view_ui(ui: &mut egui::Ui, code: &str) {
@@ -79,7 +77,7 @@ fn test_egui_e2e() {
         let full_output = ctx.run(raw_input.clone(), |ctx| {
             demo_windows.ui(ctx);
         });
-        let clipped_primitives = ctx.tessellate(full_output.shapes, ViewportId::ROOT);
+        let clipped_primitives = ctx.tessellate(full_output.shapes);
         assert!(!clipped_primitives.is_empty());
     }
 }
@@ -98,7 +96,7 @@ fn test_egui_zero_window_size() {
         let full_output = ctx.run(raw_input.clone(), |ctx| {
             demo_windows.ui(ctx);
         });
-        let clipped_primitives = ctx.tessellate(full_output.shapes, ViewportId::ROOT);
+        let clipped_primitives = ctx.tessellate(full_output.shapes);
         assert!(
             clipped_primitives.is_empty(),
             "There should be nothing to show, has at least one primitive with clip_rect: {:?}",

crates/egui_glow/src/winit.rs

@@ -77,7 +77,7 @@ impl EguiGlow {
             self.painter.set_texture(id, &image_delta);
         }
 
-        let clipped_primitives = self.egui_ctx.tessellate(shapes, ViewportId::ROOT);
+        let clipped_primitives = self.egui_ctx.tessellate(shapes);
         let dimensions: [u32; 2] = window.inner_size().into();
         self.painter.paint_primitives(
             dimensions,