forked from 1b-agent/opencadstudio-upstream
Hakan SevenandClaude Opus 4.7
ef1f9a08d6
Joining the OpenAEC Foundation (open-aec.com). Crate/struct become OpenCADStudio, user-facing strings use the spaced "Open CAD Studio" form, repo URLs point to HakanSeven12/open-cad-studio. Logo (window icon + assets/logo.svg) redrawn with OCS initials. Drop examples/ binaries — unused. Co-Authored-By: Claude Opus 4.7 <[email protected]>
94 lines
2.7 KiB
Rust
94 lines
2.7 KiB
Rust
// STL binary export — converts all tessellated MeshModels in the scene to a
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// single binary STL file.
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//
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// Binary STL format:
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// 80-byte header
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// 4-byte triangle count (u32 LE)
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// Per triangle (50 bytes):
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// 3 × f32 normal
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// 3 × 3 × f32 vertices
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// 2-byte attribute (0)
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use std::io::Write;
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use crate::scene::mesh_model::MeshModel;
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/// Build a binary STL byte buffer from a slice of mesh models.
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/// Returns `None` if there are no triangles to export.
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pub fn build_stl(meshes: &[&MeshModel]) -> Option<Vec<u8>> {
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// Collect all triangles.
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struct Tri {
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normal: [f32; 3],
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v: [[f32; 3]; 3],
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}
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let mut tris: Vec<Tri> = Vec::new();
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for mesh in meshes {
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let verts = &mesh.verts;
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let idx = &mesh.indices;
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let n_tri = idx.len() / 3;
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for t in 0..n_tri {
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let i0 = idx[t * 3] as usize;
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let i1 = idx[t * 3 + 1] as usize;
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let i2 = idx[t * 3 + 2] as usize;
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if i0 >= verts.len() || i1 >= verts.len() || i2 >= verts.len() {
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continue;
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}
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let a = verts[i0];
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let b = verts[i1];
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let c = verts[i2];
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// Compute face normal.
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let normal = if !mesh.normals.is_empty() && i0 < mesh.normals.len() {
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mesh.normals[i0]
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} else {
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let ab = [b[0] - a[0], b[1] - a[1], b[2] - a[2]];
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let ac = [c[0] - a[0], c[1] - a[1], c[2] - a[2]];
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let nx = ab[1] * ac[2] - ab[2] * ac[1];
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let ny = ab[2] * ac[0] - ab[0] * ac[2];
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let nz = ab[0] * ac[1] - ab[1] * ac[0];
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let len = (nx * nx + ny * ny + nz * nz).sqrt().max(f32::EPSILON);
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[nx / len, ny / len, nz / len]
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};
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tris.push(Tri {
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normal,
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v: [a, b, c],
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});
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}
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}
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if tris.is_empty() {
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return None;
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}
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let mut buf: Vec<u8> = Vec::with_capacity(84 + tris.len() * 50);
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// 80-byte header.
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let mut header = [0u8; 80];
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let title = b"Open CAD Studio STL export";
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header[..title.len()].copy_from_slice(title);
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buf.extend_from_slice(&header);
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// Triangle count.
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buf.extend_from_slice(&(tris.len() as u32).to_le_bytes());
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for tri in &tris {
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// Normal.
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for &f in &tri.normal {
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buf.write_all(&f.to_le_bytes()).ok()?;
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}
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// Vertices.
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for v in &tri.v {
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for &f in v {
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buf.write_all(&f.to_le_bytes()).ok()?;
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}
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}
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// Attribute byte count = 0.
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buf.extend_from_slice(&0u16.to_le_bytes());
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}
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Some(buf)
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}
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