microcad-export 0.5.0

// Copyright © 2025-2026 The µcad authors <info@microcad.xyz>
// SPDX-License-Identifier: AGPL-3.0-or-later

//! Write primitives to STL ([`WriteSvg`] trait implementations).

use microcad_core::{Geometry3D, Manifold, Transformed3D, TriangleMesh};
use microcad_lang::model::{Element, Model};

use crate::stl::{StlWriter, WriteStl};

impl WriteStl for TriangleMesh {
    fn write_stl(&self, writer: &mut StlWriter) -> std::io::Result<()> {
        self.triangles()
            .try_for_each(|tri| writer.write_triangle(&tri))
    }
}

impl WriteStl for Manifold {
    fn write_stl(&self, writer: &mut StlWriter) -> std::io::Result<()> {
        let triangle_mesh: TriangleMesh = self.to_mesh().into();
        triangle_mesh.write_stl(writer)
    }
}

impl WriteStl for Geometry3D {
    fn write_stl(&self, writer: &mut StlWriter) -> std::io::Result<()> {
        match self {
            Geometry3D::Mesh(triangle_mesh) => triangle_mesh.write_stl(writer),
            Geometry3D::Manifold(manifold) => manifold.write_stl(writer),
            _ => unreachable!("Can only write triangle geometries to STL"),
        }
    }
}

impl WriteStl for Model {
    fn write_stl(&self, writer: &mut StlWriter) -> std::io::Result<()> {
        let self_ = self.borrow();
        // Recurse into groups.
        if matches!(self_.element(), Element::Group | Element::Multiplicity) {
            self_
                .children()
                .try_for_each(|model| model.write_stl(writer))?;
            return Ok(());
        }

        let output = self_.output();
        let geometry = &output.geometry;
        let mat = output.world_matrix.expect("Some matrix");
        match geometry {
            Some(microcad_lang::render::GeometryOutput::Geometry3D(geometry)) => {
                geometry.transformed_3d(&mat).write_stl(writer)
            }
            Some(_) => Ok(()),
            None => self_
                .children()
                .try_for_each(|model| model.write_stl(writer)),
        }
    }
}