From 24de2968a352249176d156943ac19e5834f791e7 Mon Sep 17 00:00:00 2001
From: MascaraSnake <jonassauer27@gmail.com>
Date: Mon, 10 Feb 2020 20:26:29 +0100
Subject: [PATCH] Some fixes for the linedef alpha field

---
 src/hardware/hw_main.c | 3 ++-
 src/p_setup.c          | 4 ++--
 src/r_segs.c           | 3 +++
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index ef7a19208..9181dc3d3 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -895,6 +895,7 @@ FBITFIELD HWR_TranstableToAlpha(INT32 transtablenum, FSurfaceInfo *pSurf)
 {
 	switch (transtablenum)
 	{
+		case 0          : pSurf->FlatColor.s.alpha = 0x00;return  PF_Masked;
 		case tr_trans10 : pSurf->FlatColor.s.alpha = 0xe6;return  PF_Translucent;
 		case tr_trans20 : pSurf->FlatColor.s.alpha = 0xcc;return  PF_Translucent;
 		case tr_trans30 : pSurf->FlatColor.s.alpha = 0xb3;return  PF_Translucent;
@@ -1842,7 +1843,7 @@ static void HWR_StoreWallRange(double startfrac, double endfrac)
 					blendmode = PF_Translucent;
 					break;
 				default:
-					if (gr_linedef->alpha > 0 && gr_linedef->alpha < FRACUNIT)
+					if (gr_linedef->alpha >= 0 && gr_linedef->alpha < FRACUNIT)
 						blendmode = HWR_TranstableToAlpha(R_GetLinedefTransTable(gr_linedef->alpha), &Surf);
 					else
 						blendmode = PF_Masked;
diff --git a/src/p_setup.c b/src/p_setup.c
index 36786eb95..78fe32d27 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -960,8 +960,6 @@ static void P_InitializeLinedef(line_t *ld)
 	ld->dx = v2->x - v1->x;
 	ld->dy = v2->y - v1->y;
 
-	ld->alpha = FRACUNIT;
-
 	ld->bbox[BOXLEFT] = min(v1->x, v2->x);
 	ld->bbox[BOXRIGHT] = max(v1->x, v2->x);
 	ld->bbox[BOXBOTTOM] = min(v1->y, v2->y);
@@ -1059,6 +1057,7 @@ static void P_LoadLinedefs(UINT8 *data)
 		ld->tag = SHORT(mld->tag);
 		memset(ld->args, 0, NUMLINEARGS*sizeof(*ld->args));
 		memset(ld->stringargs, 0x00, NUMLINESTRINGARGS*sizeof(*ld->stringargs));
+		ld->alpha = FRACUNIT;
 		P_SetLinedefV1(i, SHORT(mld->v1));
 		P_SetLinedefV2(i, SHORT(mld->v2));
 
@@ -1654,6 +1653,7 @@ static void P_LoadTextmap(void)
 		ld->tag = 0;
 		memset(ld->args, 0, NUMLINEARGS*sizeof(*ld->args));
 		memset(ld->stringargs, 0x00, NUMLINESTRINGARGS*sizeof(*ld->stringargs));
+		ld->alpha = FRACUNIT;
 		ld->sidenum[0] = 0xffff;
 		ld->sidenum[1] = 0xffff;
 
diff --git a/src/r_segs.c b/src/r_segs.c
index 3ed6bee77..2f0514256 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -337,6 +337,9 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 	windowbottom = windowtop = sprbotscreen = INT32_MAX;
 
 	ldef = curline->linedef;
+	if (!ldef->alpha)
+		return;
+
 	if (ldef->alpha > 0 && ldef->alpha < FRACUNIT)
 	{
 		dc_transmap = transtables + ((R_GetLinedefTransTable(ldef->alpha) - 1) << FF_TRANSSHIFT);