We resolved **Issue 4.3 (Severe Per-Frame Allocation in Rendering
Loop)** by removing the intermediate `MeshData` structure and storing
`macroquad::prelude::Mesh` directly in
[`DrawCommand::Mesh`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/state.rs).
[`DrawCommand`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/state.rs)
- Dropped `Clone` and `Debug` derives from
[`Turtle`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/state.rs#L58)
and
[`DrawCommand`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/state.rs#L351),
accommodating Macroquad's `Mesh` which does not implement these
traits.
- Changed
[`DrawCommand::Mesh`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/state.rs#L353)
to the tuple variant `DrawCommand::Mesh(macroquad::prelude::Mesh)`.
- Deleted `struct MeshData` and its `to_mesh` method.
[`tessellation.rs`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs)
- Renamed `build_mesh_data` to
[`build_mesh`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs#L35)
returning `macroquad::prelude::Mesh { vertices, indices, texture: None
}` directly.
- Updated
[`tessellate_polygon`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs#L71),
[`tessellate_multi_contour`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs#L116),
[`tessellate_stroke`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs#L214),
[`tessellate_circle`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs#L259),
and
[`tessellate_arc`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tessellation.rs#L308)
to return `Result<Mesh, Box<dyn std::error::Error>>`.
[`drawing.rs`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs)
- In the main drawing loop
([`drawing.rs:36-38`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs#L36-L38)):
```rust
DrawCommand::Mesh(mesh) => {
draw_mesh(mesh);
}
```
Now borrows `&Mesh` directly from the command vector with **0 heap
allocations and 0 vector clones per frame**.
- Updated fill preview ([line
228](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs#L228)),
tween arc/center indicators ([lines 309,
329](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs#L309)),
and turtle shape drawing ([line
349](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs#L349))
to pass `&mesh` directly to `draw_mesh(&mesh)` without vector cloning.
[`execution.rs`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/execution.rs)
- Updated
[`commands.push(DrawCommand::Mesh(mesh))`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/execution.rs#L135)
and
[`tessellate_command`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/execution.rs#L337).
- Updated
[`test_forward_left_forward`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/execution.rs#L487)
to instantiate `mut state` directly without dummy cloning.
---
```bash
cargo test --lib
```
Output:
```
running 10 tests
test circle_geometry::tests::test_circle_left_geometry ... ok
test circle_geometry::tests::test_circle_right_geometry ... ok
test general::angle::tests::degrees_to_radians_roundtrip ... ok
test general::angle::tests::from_integer ... ok
test execution::tests::test_forward_left_forward ... ok
test general::angle::tests::negation ... ok
test tweening::tests::test_animated_mode_pops_to_current_tween ... ok
test tweening::tests::test_instant_mode_drains_queue ... ok
test
tweening::tests::test_instant_mode_respects_batch_limit_and_retains_pending
... ok
test tweening::tests::test_streaming_append_commands_does_not_accumulate
... ok
test result: ok. 10 passed; 0 failed; 0 ignored; 0 measured; 0 filtered
out; finished in 0.00s
```
All targets verified with `cargo check --all-targets` and `cargo clippy
--lib`.
turtle-lib
The main turtle graphics library built on Macroquad with Lyon tessellation.
See the main README for complete documentation.