Simplify signature or Operation::triangles

This is less performance-friendly, due to the additional allocations
that might be required. But for now, it's easier to work with, I think.
I can revisit the performance implications later again, when my thinking
around this whole API has solidified a bit more.

experiments/2024-12-09/src/export.rs

@@ -1,10 +1,9 @@
 use std::{collections::BTreeMap, fs::File};
 
-use crate::geometry::{Operation, Shape, TriMesh};
+use crate::geometry::{Operation, Shape};
 
 pub fn export(shape: &Shape) -> anyhow::Result<()> {
-    let mut tri_mesh = TriMesh::new();
-    shape.triangles(&mut tri_mesh);
+    let tri_mesh = shape.triangles();
 
     let mut indices_by_vertex = BTreeMap::new();
 

experiments/2024-12-09/src/geometry/operation.rs

@@ -3,7 +3,7 @@ use std::{fmt, ops::Deref, rc::Rc};
 use super::tri_mesh::TriMesh;
 
 pub trait Operation: fmt::Display {
-    fn triangles(&self, mesh: &mut TriMesh);
+    fn triangles(&self) -> TriMesh;
     fn children(&self) -> Vec<AnyOp>;
 }
 
@@ -68,8 +68,8 @@ impl fmt::Display for AnyOp {
 }
 
 impl Operation for AnyOp {
-    fn triangles(&self, mesh: &mut TriMesh) {
-        self.inner.triangles(mesh);
+    fn triangles(&self) -> TriMesh {
+        self.inner.triangles()
     }
 
     fn children(&self) -> Vec<AnyOp> {

experiments/2024-12-09/src/geometry/shape.rs

@@ -31,9 +31,11 @@ impl fmt::Display for Shape {
 }
 
 impl Operation for Shape {
-    fn triangles(&self, mesh: &mut TriMesh) {
+    fn triangles(&self) -> TriMesh {
         if let Some(op) = self.sequence.last() {
-            op.triangles(mesh);
+            op.triangles()
+        } else {
+            TriMesh::new()
         }
     }
 
@@ -52,11 +54,14 @@ struct OperationInSequence {
 }
 
 impl Operation for OperationInSequence {
-    fn triangles(&self, mesh: &mut TriMesh) {
-        if let Some(op) = &self.previous {
-            op.triangles(mesh);
-        }
-        self.operation.triangles(mesh);
+    fn triangles(&self) -> TriMesh {
+        let mesh = if let Some(op) = &self.previous {
+            op.triangles()
+        } else {
+            TriMesh::new()
+        };
+
+        mesh.merge(self.operation.triangles())
     }
 
     fn children(&self) -> Vec<AnyOp> {

experiments/2024-12-09/src/geometry/tri_mesh.rs

@@ -10,4 +10,9 @@ impl TriMesh {
             triangles: Vec::new(),
         }
     }
+
+    pub fn merge(mut self, other: Self) -> Self {
+        self.triangles.extend(other.triangles);
+        self
+    }
 }

experiments/2024-12-09/src/geometry/triangle.rs

@@ -27,8 +27,10 @@ impl fmt::Display for Triangle {
 }
 
 impl Operation for Triangle {
-    fn triangles(&self, mesh: &mut TriMesh) {
-        mesh.triangles.push(self.clone())
+    fn triangles(&self) -> TriMesh {
+        TriMesh {
+            triangles: vec![self.clone()],
+        }
     }
 
     fn children(&self) -> Vec<AnyOp> {

experiments/2024-12-09/src/render/geometry.rs

@@ -1,7 +1,7 @@
 use glam::Vec3;
 use wgpu::util::DeviceExt;
 
-use crate::geometry::{Operation, TriMesh};
+use crate::geometry::Operation;
 
 use super::vertex::Vertex;
 
@@ -13,8 +13,7 @@ pub struct Geometry {
 
 impl Geometry {
     pub fn new(device: &wgpu::Device, operation: &dyn Operation) -> Self {
-        let mut tri_mesh = TriMesh::new();
-        operation.triangles(&mut tri_mesh);
+        let tri_mesh = operation.triangles();
 
         let mut indices = Vec::new();
         let mut vertices = Vec::new();

experiments/2024-12-09/src/topology/face.rs

@@ -43,7 +43,7 @@ impl fmt::Display for Face {
 }
 
 impl Operation for Face {
-    fn triangles(&self, mesh: &mut TriMesh) {
+    fn triangles(&self) -> TriMesh {
         // This is a placeholder implementation that only supports convex faces.
 
         let mut triangulation =
@@ -81,6 +81,7 @@ impl Operation for Face {
             )
             .unwrap();
 
+        let mut mesh = TriMesh::new();
         mesh.triangles
             .extend(triangulation.inner_faces().map(|triangle| {
                 let points = triangle
@@ -88,6 +89,8 @@ impl Operation for Face {
                     .map(|vertex| vertex.data().point_vertex);
                 Triangle { points }
             }));
+
+        mesh
     }
 
     fn children(&self) -> Vec<AnyOp> {

experiments/2024-12-09/src/topology/vertex.rs

@@ -29,7 +29,9 @@ impl fmt::Display for Vertex {
 }
 
 impl Operation for Vertex {
-    fn triangles(&self, _: &mut TriMesh) {}
+    fn triangles(&self) -> TriMesh {
+        TriMesh::new()
+    }
 
     fn children(&self) -> Vec<AnyOp> {
         Vec::new()

experiments/2024-12-09/src/view.rs

@@ -128,8 +128,8 @@ impl fmt::Display for OperationView {
 }
 
 impl Operation for OperationView {
-    fn triangles(&self, mesh: &mut TriMesh) {
-        self.operation.triangles(mesh);
+    fn triangles(&self) -> TriMesh {
+        self.operation.triangles()
     }
 
     fn children(&self) -> Vec<AnyOp> {