From 6ca806a8c0395e4283a7be477e9d1a06782317a5 Mon Sep 17 00:00:00 2001
From: Monster Iestyn <iestynjealous@ntlworld.com>
Date: Sat, 31 Dec 2016 20:44:16 +0000
Subject: [PATCH] Fix FOF lighting being stupid with repeating midtextures.

---
 src/r_defs.h | 1 +
 src/r_segs.c | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/src/r_defs.h b/src/r_defs.h
index 2c5860ee..e1ffca7e 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -203,6 +203,7 @@ typedef struct r_lightlist_s
 	fixed_t heightstep;
 	fixed_t botheight;
 	fixed_t botheightstep;
+	fixed_t startheight; // for repeating midtextures
 	INT16 lightlevel;
 	extracolormap_t *extra_colormap;
 	lighttable_t *rcolormap;
diff --git a/src/r_segs.c b/src/r_segs.c
index ab501082..8f271bfe 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -394,6 +394,7 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 			rlight->height = (centeryfrac) - FixedMul((light->height - viewz), spryscale);
 			rlight->heightstep = -FixedMul(rw_scalestep, (light->height - viewz));
 #endif
+			rlight->startheight = rlight->height; // keep starting value here to reset for each repeat
 			rlight->lightlevel = *light->lightlevel;
 			rlight->extra_colormap = light->extra_colormap;
 			rlight->flags = light->flags;
@@ -487,6 +488,14 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 		{
 			rw_scalestep = ds->scalestep;
 			spryscale = ds->scale1 + (x1 - ds->x1)*rw_scalestep;
+			if (dc_numlights)
+			{ // reset all lights to their starting heights
+				for (i = 0; i < dc_numlights; i++)
+				{
+					rlight = &dc_lightlist[i];
+					rlight->height = rlight->startheight;
+				}
+			}
 		}
 
 #ifndef ESLOPE