From 8becebf8501b46afc1103b0e27e7d35f8813a6f5 Mon Sep 17 00:00:00 2001
From: Jan Wielkiewicz <tona_kosmicznego_smiecia@interia.pl>
Date: Fri, 23 Aug 2024 20:46:34 +0200
Subject: [PATCH] intersect: Fix cpml.intersect.segment_segment bug.

---
 modules/intersect.lua | 50 ++++++++++++++++++++++---------------------
 modules/vec3.lua      |  8 +++++++
 2 files changed, 34 insertions(+), 24 deletions(-)

diff --git a/modules/intersect.lua b/modules/intersect.lua
index c8d7086..3d5d04c 100644
--- a/modules/intersect.lua
+++ b/modules/intersect.lua
@@ -305,35 +305,37 @@ end
 -- e    is a number
 function intersect.segment_segment(a, b, e)
 	local c, d = intersect.line_line(a, b, e)
+	local A = {vec3.component_sort(a[1], a[2])}
+	local B = {vec3.component_sort(b[1], b[2])}
 
 	if c and ((
-		a[1].x <= c[1].x and
-		a[1].y <= c[1].y and
-		a[1].z <= c[1].z and
-		c[1].x <= a[2].x and
-		c[1].y <= a[2].y and
-		c[1].z <= a[2].z
+		A[1].x <= c[1].x and
+		A[1].y <= c[1].y and
+		A[1].z <= c[1].z and
+		c[1].x <= A[2].x and
+		c[1].y <= A[2].y and
+		c[1].z <= A[2].z
 	) or (
-		a[1].x >= c[1].x and
-		a[1].y >= c[1].y and
-		a[1].z >= c[1].z and
-		c[1].x >= a[2].x and
-		c[1].y >= a[2].y and
-		c[1].z >= a[2].z
+		A[1].x >= c[1].x and
+		A[1].y >= c[1].y and
+		A[1].z >= c[1].z and
+		c[1].x >= A[2].x and
+		c[1].y >= A[2].y and
+		c[1].z >= A[2].z
 	)) and ((
-		b[1].x <= c[2].x and
-		b[1].y <= c[2].y and
-		b[1].z <= c[2].z and
-		c[2].x <= b[2].x and
-		c[2].y <= b[2].y and
-		c[2].z <= b[2].z
+		B[1].x <= c[2].x and
+		B[1].y <= c[2].y and
+		B[1].z <= c[2].z and
+		c[2].x <= B[2].x and
+		c[2].y <= B[2].y and
+		c[2].z <= B[2].z
 	) or (
-		b[1].x >= c[2].x and
-		b[1].y >= c[2].y and
-		b[1].z >= c[2].z and
-		c[2].x >= b[2].x and
-		c[2].y >= b[2].y and
-		c[2].z >= b[2].z
+		B[1].x >= c[2].x and
+		B[1].y >= c[2].y and
+		B[1].z >= c[2].z and
+		c[2].x >= B[2].x and
+		c[2].y >= B[2].y and
+		c[2].z >= B[2].z
 	)) then
 		return c, d
 	end
diff --git a/modules/vec3.lua b/modules/vec3.lua
index b653506..d03e43f 100644
--- a/modules/vec3.lua
+++ b/modules/vec3.lua
@@ -309,6 +309,14 @@ function vec3.component_max(a, b)
 	return new(math.max(a.x, b.x), math.max(a.y, b.y), math.max(a.z, b.z))
 end
 
+--- Return the component-wise minimum and maximum of two vectors.
+-- @tparam vec3 a Left hand operand
+-- @tparam vec3 b Right hand operand
+-- @treturn vec3, vec3 sorted vectors
+function vec3.component_sort(a, b)
+	return vec3.component_min(a, b), vec3.component_max(a, b)
+end
+
 -- Negate x axis only of vector.
 -- @tparam vec3 a Vector to x-flip.
 -- @treturn vec3 x-flipped vector