From 7bbdfb41f6c0f07f9b455e8f8f241d44b0fa377b Mon Sep 17 00:00:00 2001 From: NetterSilver <133535268+Silvertree2010@users.noreply.github.com> Date: Tue, 20 Oct 2026 15:58:52 +0200 Subject: [PATCH] Return identity from Mat3::square_to_quad for a degenerate quad Found while testing crates/geom/src/lib.rs:252-264 Co-Authored-By: Claude Haiku 5.5 Co-Authored-By: Claude Sonnet 5.5 --- crates/geom/src/lib.rs | 3 +++ crates/geom/tests/square_to_quad.rs | 13 +++++++++++++ 2 files changed, 16 insertions(+) create mode 100644 crates/geom/tests/square_to_quad.rs diff --git a/crates/geom/src/lib.rs b/crates/geom/src/lib.rs index a03c9d46c..cbc9c1072 100644 --- a/crates/geom/src/lib.rs +++ b/crates/geom/src/lib.rs @@ -261,6 +261,9 @@ impl Mat3 { return Mat3([[x1 - x0, x3 - x0, x0], [y1 - y0, y3 - y0, y0], [0.0, 0.0, 1.0]]); } let den = dx1 * dy2 - dx2 * dy1; + if den == 0.0 || !den.is_finite() { + return Mat3::IDENTITY; + } let g = (sx * dy2 - dx2 * sy) / den; let h = (dx1 * sy - sx * dy1) / den; Mat3([[x1 - x0 + g * x1, x3 - x0 + h * x3, x0], [y1 - y0 + g * y1, y3 - y0 + h * y3, y0], [g, h, 1.0]]) diff --git a/crates/geom/tests/square_to_quad.rs b/crates/geom/tests/square_to_quad.rs new file mode 100644 index 000000000..3dd409a58 --- /dev/null +++ b/crates/geom/tests/square_to_quad.rs @@ -0,0 +1,13 @@ +use effectcraft_geom::{Mat3, vec2}; + +#[test] +fn square_to_quad_degenerate_is_finite() { + let m = Mat3::square_to_quad([vec2(0.0, 5.0), vec2(0.0, 0.0), vec2(10.0, 0.0), vec2(20.0, 0.0)]); + assert!(m.0.iter().flatten().all(|v| v.is_finite()), "non-finite: {m:?}"); +} + +#[test] +fn square_to_quad_regular_is_finite() { + let m = Mat3::square_to_quad([vec2(0.0, 0.0), vec2(10.0, 0.0), vec2(8.0, 6.0), vec2(0.0, 5.0)]); + assert!(m.0.iter().flatten().all(|v| v.is_finite())); +}