From 75ade552e20b4d6cc46543862305304202a9d0d3 Mon Sep 17 00:00:00 2001
From: William Linna <wlinna@proton.me>
Date: Wed, 1 May 2024 13:58:59 +0300
Subject: [PATCH] fix incorrect non-solid point projection called by
 project_local_point_and_get_location (#195)

* Fix d_abc and d_bc computation in project_local_point_and_get_location
* Fix https://github.com/dimforge/parry/issues/194
---
 crates/parry2d/tests/lib.rs                  |  1 +
 crates/parry2d/tests/query/mod.rs            |  1 +
 crates/parry2d/tests/query/point_triangle.rs | 20 ++++++++++++++++++++
 src/query/point/point_triangle.rs            |  4 ++--
 4 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 crates/parry2d/tests/query/mod.rs
 create mode 100644 crates/parry2d/tests/query/point_triangle.rs

diff --git a/crates/parry2d/tests/lib.rs b/crates/parry2d/tests/lib.rs
index 206d0874..4557202e 100644
--- a/crates/parry2d/tests/lib.rs
+++ b/crates/parry2d/tests/lib.rs
@@ -4,3 +4,4 @@ extern crate nalgebra as na;
 extern crate parry2d;
 
 mod geometry;
+mod query;
diff --git a/crates/parry2d/tests/query/mod.rs b/crates/parry2d/tests/query/mod.rs
new file mode 100644
index 00000000..b06213c4
--- /dev/null
+++ b/crates/parry2d/tests/query/mod.rs
@@ -0,0 +1 @@
+mod point_triangle;
diff --git a/crates/parry2d/tests/query/point_triangle.rs b/crates/parry2d/tests/query/point_triangle.rs
new file mode 100644
index 00000000..75fde225
--- /dev/null
+++ b/crates/parry2d/tests/query/point_triangle.rs
@@ -0,0 +1,20 @@
+use parry2d::{math::Point, query::PointQuery, shape::Triangle};
+
+#[test]
+fn project_local_point_point_on_ab() {
+    let verts = [
+        Point::new(2.0, 1.0),
+        Point::new(0.0, 1.0),
+        Point::new(1.0, 0.0),
+    ];
+    let tri1 = Triangle::new(verts[0], verts[1], verts[2]);
+    let tri2 = Triangle::new(verts[2], verts[0], verts[1]);
+
+    let query_pt = Point::new(1.4, 1.0);
+
+    let proj1 = tri1.project_local_point(&query_pt, false); // Used to fail on 0.14 and earlier
+    let proj2 = tri2.project_local_point(&query_pt, false);
+
+    assert_eq!(proj1.point, proj2.point);
+    assert_eq!(proj1.point, query_pt);
+}
diff --git a/src/query/point/point_triangle.rs b/src/query/point/point_triangle.rs
index a37a0c8f..09895198 100644
--- a/src/query/point/point_triangle.rs
+++ b/src/query/point/point_triangle.rs
@@ -252,8 +252,8 @@ impl PointQueryWithLocation for Triangle {
 
             let bc = c - b;
             let d_ab = ap.norm_squared() - (ab.norm_squared() * v * v);
-            let d_ac = ap.norm_squared() - (ac.norm_squared() * u * u);
-            let d_bc = bp.norm_squared() - (bc.norm_squared() * w * w);
+            let d_ac = ap.norm_squared() - (ac.norm_squared() * w * w);
+            let d_bc = bp.norm_squared() - (bc.norm_squared() * u * u);
 
             let proj;
             let loc;