Merge branch 'portal-fix' into 'next'

Some fixes for portals

Specifically the following things are fixed in this branch:

* a memory leak resulting from not clearing away clipping-related arrays each tic you view a portal
* a very specific crash to do with portals sometimes (unintentionally) using a hack on drawsegs that don't actually belong to them ...which results in a crash if the drawsegs in question have midtextures. I reported it on the MB a year ago, with a test map included there: https://mb.srb2.org/showthread.php?t=38199&page=4#79
* another specific crash to do with mirrored (horizontally flipped) sprites that are scaled, particularly when you cover up the left edge of them via portals at the least. Needs more testing to be absolutely sure this is fixed, and is also reproducable in the test map linked in the post above

May be fine to merge changes into master too, I don't really know exactly

See merge request !42

src/r_bsp.c

@@ -26,6 +26,7 @@ side_t *sidedef;
 line_t *linedef;
 sector_t *frontsector;
 sector_t *backsector;
+boolean portalline; // is curline a portal seg?
 
 // very ugly realloc() of drawsegs at run-time, I upped it to 512
 // instead of 256.. and someone managed to send me a level with
@@ -378,6 +379,7 @@ static void R_AddLine(seg_t *line)
 		return;
 
 	curline = line;
+	portalline = false;
 
 	// OPTIMIZE: quickly reject orthogonal back sides.
 	angle1 = R_PointToAngle(line->v1->x, line->v1->y);
@@ -431,7 +433,7 @@ static void R_AddLine(seg_t *line)
 	backsector = line->backsector;
 
 	// Portal line
-	if (line->linedef->special == 40 && P_PointOnLineSide(viewx, viewy, line->linedef) == 0)
+	if (line->linedef->special == 40 && line->side == 0)
 	{
 		if (portalrender < cv_maxportals.value)
 		{

src/r_bsp.h

@@ -23,6 +23,7 @@ extern side_t *sidedef;
 extern line_t *linedef;
 extern sector_t *frontsector;
 extern sector_t *backsector;
+extern boolean portalline; // is curline a portal seg?
 
 // drawsegs are allocated on the fly... see r_segs.c
 

src/r_defs.h

@@ -667,6 +667,8 @@ typedef struct drawseg_s
 	INT32 numthicksides;
 	fixed_t frontscale[MAXVIDWIDTH];
 
+	UINT8 portalpass; // if > 0 and <= portalrender, do not affect sprite clipping
+
 #ifdef ESLOPE
 	fixed_t maskedtextureheight[MAXVIDWIDTH]; // For handling sloped midtextures
 

src/r_main.c

@@ -91,7 +91,6 @@ typedef struct portal_pair
 	INT16 *ceilingclip;
 	INT16 *floorclip;
 	fixed_t *frontscale;
-	size_t seg;
 } portal_pair;
 portal_pair *portal_base, *portal_cap;
 line_t *portalclipline;
@@ -1230,7 +1229,7 @@ void R_AddPortal(INT32 line1, INT32 line2, INT32 x1, INT32 x2)
 	portal->start = x1;
 	portal->end = x2;
 
-	portal->seg = ds_p-drawsegs;
+	portalline = true; // this tells R_StoreWallRange that curline is a portal seg
 
 	portal->viewx = viewx;
 	portal->viewy = viewy;
@@ -1344,14 +1343,6 @@ void R_RenderPlayerView(player_t *player)
 
 		validcount++;
 
-		if (portal->seg)
-		{
-			// Push the portal's old drawseg out of the way so it isn't interfering with sprite clipping. -Red
-			drawseg_t *seg = drawsegs+portal->seg;
-			seg->scale1 = 0;
-			seg->scale2 = 0;
-		}
-
 		R_RenderBSPNode((INT32)numnodes - 1);
 		R_ClipSprites();
 		//R_DrawPlanes();
@@ -1360,6 +1351,9 @@ void R_RenderPlayerView(player_t *player)
 		// okay done. free it.
 		portalcullsector = NULL; // Just in case...
 		portal_base = portal->next;
+		Z_Free(portal->ceilingclip);
+		Z_Free(portal->floorclip);
+		Z_Free(portal->frontscale);
 		Z_Free(portal);
 	}
 	// END PORTAL RENDERING

src/r_segs.c

@@ -2887,6 +2887,11 @@ void R_StoreWallRange(INT32 start, INT32 stop)
 		R_RenderSegLoop();
 	colfunc = wallcolfunc;
 
+	if (portalline) // if curline is a portal, set portalrender for drawseg
+		ds_p->portalpass = portalrender+1;
+	else
+		ds_p->portalpass = 0;
+
 	// save sprite clipping info
 	if (((ds_p->silhouette & SIL_TOP) || maskedtexture) && !ds_p->sprtopclip)
 	{

src/r_things.c

@@ -834,10 +834,10 @@ static void R_DrawVisSprite(vissprite_t *vis)
 		dc_texturemid = FixedDiv(dc_texturemid,this_scale);
 
 		//Oh lordy, mercy me. Don't freak out if sprites go offscreen!
-		if (vis->xiscale > 0)
+		/*if (vis->xiscale > 0)
 			frac = FixedDiv(frac, this_scale);
 		else if (vis->x1 <= 0)
-			frac = (vis->x1 - vis->x2) * vis->xiscale;
+			frac = (vis->x1 - vis->x2) * vis->xiscale;*/
 
 		sprtopscreen = centeryfrac - FixedMul(dc_texturemid, spryscale);
 		//dc_hires = 1;
@@ -1301,7 +1301,7 @@ static void R_ProjectSprite(mobj_t *thing)
 	}
 
 	if (vis->x1 > x1)
-		vis->startfrac += vis->xiscale*(vis->x1-x1);
+		vis->startfrac += FixedDiv(vis->xiscale, this_scale)*(vis->x1-x1);
 
 	//Fab: lumppat is the lump number of the patch to use, this is different
 	//     than lumpid for sprites-in-pwad : the graphics are patched
@@ -2053,6 +2053,9 @@ void R_ClipSprites(void)
 				continue;
 			}
 
+			if (ds->portalpass > 0 && ds->portalpass <= portalrender)
+				continue; // is a portal
+
 			r1 = ds->x1 < spr->x1 ? spr->x1 : ds->x1;
 			r2 = ds->x2 > spr->x2 ? spr->x2 : ds->x2;