From faaf48d6a764529f8b4e2a058a5380296904a0c6 Mon Sep 17 00:00:00 2001
From: Rob Kelly <contact@robkel.ly>
Date: Fri, 7 Mar 2025 18:18:50 -0700
Subject: [PATCH] Refactored generic geometric utilities out of GunkBody

---
 src/util/geometry_tools.gd       | 25 +++++++++++++++++++++++++
 src/util/geometry_tools.gd.uid   |  1 +
 src/world/gunk_body/gunk_body.gd | 27 ++-------------------------
 3 files changed, 28 insertions(+), 25 deletions(-)
 create mode 100644 src/util/geometry_tools.gd
 create mode 100644 src/util/geometry_tools.gd.uid

diff --git a/src/util/geometry_tools.gd b/src/util/geometry_tools.gd
new file mode 100644
index 0000000..8589f68
--- /dev/null
+++ b/src/util/geometry_tools.gd
@@ -0,0 +1,25 @@
+class_name GeometryTools
+## Utilities for specialized geometric operations.
+
+
+## Transform cartesian coordinates to barycentric wrt the given triangle.
+static func barycentric(p: Vector3, a: Vector3, b: Vector3, c: Vector3) -> Vector3:
+	var v0 := b - a
+	var v1 := c - a
+	var v2 := p - a
+	var d00 := v0.dot(v0)
+	var d01 := v0.dot(v1)
+	var d11 := v1.dot(v1)
+	var d20 := v2.dot(v0)
+	var d21 := v2.dot(v1)
+	var denom := d00 * d11 - d01 * d01
+	var v := (d11 * d20 - d01 * d21) / denom
+	var w := (d00 * d21 - d01 * d20) / denom
+	var u := 1.0 - v - w
+	return Vector3(u, v, w)
+
+
+## Is the given point on the planar triangle defined by v1, v2, and v3?
+static func is_in_triangle(point: Vector3, v1: Vector3, v2: Vector3, v3: Vector3) -> bool:
+	var bc := barycentric(point, v1, v2, v3)
+	return (bc.x > 0 and bc.x < 1) and (bc.y > 0 and bc.y < 1) and (bc.z > 0 and bc.z < 1)
diff --git a/src/util/geometry_tools.gd.uid b/src/util/geometry_tools.gd.uid
new file mode 100644
index 0000000..0233ed5
--- /dev/null
+++ b/src/util/geometry_tools.gd.uid
@@ -0,0 +1 @@
+uid://cgh4qc5whocql
diff --git a/src/world/gunk_body/gunk_body.gd b/src/world/gunk_body/gunk_body.gd
index 2f95c52..dba6680 100644
--- a/src/world/gunk_body/gunk_body.gd
+++ b/src/world/gunk_body/gunk_body.gd
@@ -118,29 +118,6 @@ func get_clear_total() -> float:
 	return total
 
 
-## Transform cartesian coordinates to barycentric wrt the given triangle.
-func _barycentric(p: Vector3, a: Vector3, b: Vector3, c: Vector3) -> Vector3:
-	var v0 := b - a
-	var v1 := c - a
-	var v2 := p - a
-	var d00 := v0.dot(v0)
-	var d01 := v0.dot(v1)
-	var d11 := v1.dot(v1)
-	var d20 := v2.dot(v0)
-	var d21 := v2.dot(v1)
-	var denom := d00 * d11 - d01 * d01
-	var v := (d11 * d20 - d01 * d21) / denom
-	var w := (d00 * d21 - d01 * d20) / denom
-	var u := 1.0 - v - w
-	return Vector3(u, v, w)
-
-
-## Is the given point on the planar triangle defined by v1, v2, and v3?
-func _is_in_triangle(point: Vector3, v1: Vector3, v2: Vector3, v3: Vector3) -> bool:
-	var bc := _barycentric(point, v1, v2, v3)
-	return (bc.x > 0 and bc.x < 1) and (bc.y > 0 and bc.y < 1) and (bc.z > 0 and bc.z < 1)
-
-
 ## Get the index of the mesh face on which the given point+normal lies.
 ##
 ## Returns -1 if the given point+normal does not lie on a mesh face within tolerance.
@@ -156,7 +133,7 @@ func _get_face(point: Vector3, normal: Vector3) -> int:
 		var v1 := meshtool.get_vertex(meshtool.get_face_vertex(i, 0))
 		var v2 := meshtool.get_vertex(meshtool.get_face_vertex(i, 1))
 		var v3 := meshtool.get_vertex(meshtool.get_face_vertex(i, 2))
-		if _is_in_triangle(point, v1, v2, v3):
+		if GeometryTools.is_in_triangle(point, v1, v2, v3):
 			min_i = i
 			min_sdist = sdist
 	return min_i
@@ -175,7 +152,7 @@ func _get_uv(point: Vector3, normal: Vector3) -> Vector2:
 	var v1 := meshtool.get_vertex(fv0)
 	var v2 := meshtool.get_vertex(fv1)
 	var v3 := meshtool.get_vertex(fv2)
-	var bc := _barycentric(point, v1, v2, v3)  # TODO memoize
+	var bc := GeometryTools.barycentric(point, v1, v2, v3)  # TODO memoize
 	var uv1 := meshtool.get_vertex_uv(fv0)
 	var uv2 := meshtool.get_vertex_uv(fv1)
 	var uv3 := meshtool.get_vertex_uv(fv2)