From e63f68e732e8e5382dbed8c33771892b16f317ff Mon Sep 17 00:00:00 2001
From: Alug <alufoliehorst@gmail.com>
Date: Sun, 8 Jun 2025 22:01:41 +0200
Subject: [PATCH] fix portal clipping being completely completely broken on
 kart maps

truly amazing
---
 src/r_portal.c | 29 +++++++++++++++++++++++++++++
 src/r_portal.h |  1 +
 src/r_segs.cpp |  6 +++---
 src/w_wad.c    |  4 ++--
 4 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/r_portal.c b/src/r_portal.c
index f5e9874d6..416dc4b6f 100644
--- a/src/r_portal.c
+++ b/src/r_portal.c
@@ -37,6 +37,32 @@ void Portal_InitList (void)
 	portal_base = portal_cap = NULL;
 }
 
+/** Store the clipping window for a portal in its given range.
+ *
+ * The window is copied from the current window at the time
+ * the function is called, so it is useful for converting one-sided
+ * lines into portals.
+ */
+void Portal_ClipRange (portal_t* portal)
+{
+	INT32 start	= portal->start;
+	INT32 end	= portal->end;
+	INT16 *ceil		= portal->ceilingclip;
+	INT16 *floor	= portal->floorclip;
+	fixed_t *scale	= portal->frontscale;
+
+	INT32 i;
+	for (i = 0; i < end-start; i++)
+	{
+		*ceil = ceilingclip[start+i];
+		ceil++;
+		*floor = floorclip[start+i];
+		floor++;
+		*scale = frontscale[start+i];
+		scale++;
+	}
+}
+
 /** Apply the clipping window from a portal.
  */
 void Portal_ClipApply (const portal_t* portal)
@@ -158,6 +184,9 @@ void Portal_Add2Lines (const INT32 line1, const INT32 line2, const INT32 x1, con
 
 	portal->clipline = line2;
 
+	if (mapnamespace == MNS_SRB2KART)
+		Portal_ClipRange(portal);
+
 	g_portal = portal; // this tells R_StoreWallRange that curline is a portal seg
 }
 
diff --git a/src/r_portal.h b/src/r_portal.h
index 60bde34bc..05fe3d977 100644
--- a/src/r_portal.h
+++ b/src/r_portal.h
@@ -58,6 +58,7 @@ void Portal_Remove		(portal_t* portal);
 void Portal_Add2Lines	(const INT32 line1, const INT32 line2, const INT32 x1, const INT32 x2);
 void Portal_AddSkybox	(const visplane_t* plane);
 
+void Portal_ClipRange (portal_t* portal);
 void Portal_ClipApply (const portal_t* portal);
 
 void Portal_AddSkyboxPortals (void);
diff --git a/src/r_segs.cpp b/src/r_segs.cpp
index 7197ee609..0565d5256 100644
--- a/src/r_segs.cpp
+++ b/src/r_segs.cpp
@@ -1596,7 +1596,7 @@ static void R_RenderSegLoop (drawcolumndata_t* dc)
 		// Portal line
 		// Spans the entire height of a single-sided line or
 		// the "window" of a double-sided line.
-		if (g_portal)
+		if (g_portal && (mapnamespace != MNS_SRB2KART))
 		{
 			I_Assert(rw_x >= g_portal->start && rw_x < g_portal->end);
 			i = rw_x - g_portal->start;
@@ -2245,7 +2245,7 @@ void R_StoreWallRange(INT32 start, INT32 stop)
 			|| frontsector->extra_colormap != backsector->extra_colormap
 			|| (frontsector->ffloors != backsector->ffloors && !Tag_Compare(&frontsector->tags, &backsector->tags))
 			// Portals block traversal behind them
-			|| g_portal
+			|| (g_portal && mapnamespace != MNS_SRB2KART)
 			// Highlighting death pits
 			|| (cv_debugfinishline.value && frontsector->damagetype != backsector->damagetype))
 		{
@@ -2283,7 +2283,7 @@ void R_StoreWallRange(INT32 start, INT32 stop)
 			|| frontsector->extra_colormap != backsector->extra_colormap
 			|| (frontsector->ffloors != backsector->ffloors && !Tag_Compare(&frontsector->tags, &backsector->tags))
 			// Portals block traversal behind them
-			|| g_portal
+			|| (g_portal && mapnamespace != MNS_SRB2KART)
 			// Highlighting death pits
 			|| (cv_debugfinishline.value && frontsector->damagetype != backsector->damagetype))
 		{
diff --git a/src/w_wad.c b/src/w_wad.c
index 6fa3f1a80..2d669bd37 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -1402,7 +1402,7 @@ lumpnum_t W_CheckNumForName(const char *name)
 	INT32 i;
 	UINT32 hash = name ? quickncasehash(name, 8) : 0;
 	lumpnum_t check = INT16_MAX;
-	
+
 	if (name == NULL)
 		return LUMPERROR;
 
@@ -1454,7 +1454,7 @@ lumpnum_t W_CheckNumForLongName(const char *name)
 	INT32 i;
 	UINT32 hash = name ? quickncasehash(name, 8) : 0;
 	lumpnum_t check = INT16_MAX;
-	
+
 	if (name == NULL)
 		return LUMPERROR;