From 186fa924cf4fb575785ba8a5db8630b0f9103fd2 Mon Sep 17 00:00:00 2001
From: NepDisk <nepdisk@noreply.codeberg.org>
Date: Sun, 5 Oct 2025 13:37:57 -0400
Subject: [PATCH] Revert "Optimize line checks on line interception"

This reverts commit bd9924b794ed5e7b89f04278d295c937a31b8afb.
---
 src/p_maputl.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/p_maputl.c b/src/p_maputl.c
index e2d08a930..0c03f61f1 100644
--- a/src/p_maputl.c
+++ b/src/p_maputl.c
@@ -107,11 +107,15 @@ void P_ClosestPointOnLine3D(const vector3_t *p, const vector3_t *Line, vector3_t
 // P_PointOnLineSide
 // Returns 0 or 1
 //
+// killough 5/3/98: reformatted, cleaned up
+// ioanch 20151228: made line const
+//
 INT32 P_PointOnLineSide(fixed_t x, fixed_t y, const line_t *line)
 {
-	// use cross product to determine side quickly
-	INT64 v = ((INT64)y - line->v1->y) * line->dx - ((INT64)x - line->v1->x) * line->dy;
-	return v > 0;
+	return
+		!line->dx ? x <= line->v1->x ? line->dy > 0 : line->dy < 0 :
+		!line->dy ? y <= line->v1->y ? line->dx < 0 : line->dx > 0 :
+		((INT64)y - line->v1->y) * line->dx >= line->dy * ((INT64)x - line->v1->x);
 }
 
 //
@@ -151,11 +155,15 @@ INT32 P_BoxOnLineSide(const fixed_t *tmbox, const line_t *ld)
 // P_PointOnDivlineSide
 // Returns 0 or 1.
 //
+// killough 5/3/98: reformatted, cleaned up
+//
 static INT32 P_PointOnDivlineSide(fixed_t x, fixed_t y, const divline_t *line)
 {
-	// use cross product to determine side quickly
-	INT64 v = ((INT64)y - line->y) * line->dx - ((INT64)x - line->x) * line->dy;
-	return v > 0;
+	return
+		line->dx == 0 ? x <= line->x ? line->dy > 0 : line->dy < 0 :
+		line->dy == 0 ? y <= line->y ? line->dx < 0 : line->dx > 0 :
+		(line->dy ^ line->dx ^ (x -= line->x) ^ (y -= line->y)) < 0 ? (line->dy ^ x) < 0 :
+		(INT64)(y) * line->dx >= (INT64)(line->dy) * x;
 }
 
 //