Vissprite clipping improvements.

Vissprites are now only clipped against their respective portal's geometry obtained from their BSP run.
Additionally, if a portal is provided, they're clipped to the portal's clip boundaries.
The work on this branch should conclude after a pair of remaining glitches are fixed.

src/r_main.c

@@ -1061,8 +1061,7 @@ void R_RenderPlayerView(player_t *player)
 	masks[nummasks - 1].drawsegs[1]		= ds_p - drawsegs;
 	masks[nummasks - 1].vissprites[1]	= visspritecount;
 
-
-	R_ClipSprites();
+	R_ClipSprites(drawsegs, NULL);
 #ifdef TIMING
 	RDMSR(0x10, &mycount);
 	mytotal += mycount; // 64bit add
@@ -1108,7 +1107,8 @@ void R_RenderPlayerView(player_t *player)
 			R_RenderBSPNode((INT32)numnodes - 1);
 			masks[nummasks - 1].drawsegs[1]		= ds_p - drawsegs;
 			masks[nummasks - 1].vissprites[1]	= visspritecount;
-			R_ClipSprites();
+
+			R_ClipSprites(ds_p - (masks[nummasks - 1].drawsegs[1] - masks[nummasks - 1].drawsegs[0]), portal);
 
 			Portal_Remove(portal);
 		}

src/r_portal.c

@@ -17,6 +17,7 @@
 #include "doomstat.h"
 #include "p_spec.h" // Skybox viewpoints
 #include "z_zone.h"
+#include "r_things.h"
 
 UINT8 portalrender;			/**< When rendering a portal, it establishes the depth of the current BSP traversal. */
 sector_t *portalcullsector;
@@ -98,9 +99,9 @@ void Portal_ClipApply (const portal_t* portal)
 portal_t* Portal_Add (const INT16 x1, const INT16 x2)
 {
 	portal_t *portal		= Z_Malloc(sizeof(portal_t), PU_LEVEL, NULL);
-	INT16 *ceilingclipsave	= Z_Malloc(sizeof(INT16)*(x2-x1), PU_LEVEL, NULL);
-	INT16 *floorclipsave	= Z_Malloc(sizeof(INT16)*(x2-x1), PU_LEVEL, NULL);
-	fixed_t *frontscalesave	= Z_Malloc(sizeof(fixed_t)*(x2-x1), PU_LEVEL, NULL);
+	INT16 *ceilingclipsave	= Z_Malloc(sizeof(INT16)*(x2-x1 + 1), PU_LEVEL, NULL);
+	INT16 *floorclipsave	= Z_Malloc(sizeof(INT16)*(x2-x1 + 1), PU_LEVEL, NULL);
+	fixed_t *frontscalesave	= Z_Malloc(sizeof(fixed_t)*(x2-x1 + 1), PU_LEVEL, NULL);
 
 	// Linked list.
 	if (!portal_base)
@@ -199,15 +200,7 @@ static void Portal_ClipVisplane (const visplane_t* plane, portal_t* portal)
 
 	for (i = 0; i < end - start; i++)
 	{
-		if (plane->bottom[i + start] == 0)
-		{
-			portal->ceilingclip[i] = 0;
-			portal->floorclip[i] = 0;
-			continue;
-		}
-
-
-		portal->ceilingclip[i] = plane->top[i + start] - 1;
+		portal->ceilingclip[i] = plane->top[i + start];
 		portal->floorclip[i] = plane->bottom[i + start] + 1;
 		portal->frontscale[i] = INT32_MAX;
 	}
@@ -230,6 +223,25 @@ void Portal_AddSkybox (const visplane_t* plane)
 	if (!(start < end))
 		return;
 
+	/** Trims a visplane's horizontal gap to match its render area.
+	 *
+	 * Visplanes' minx/maxx may sometimes exceed the area they're
+	 * covering. This merely adjusts the boundaries to the next
+	 * valid area.
+	 */
+
+	while (plane->bottom[start] == 0 && plane->top[start] == 65535 && start < end)
+	{
+		start++;
+	}
+
+
+	while (plane->bottom[end - 1] == 0 && plane->top[start] == 65535 && end > start)
+	{
+		end--;
+	}
+
+
 	portal = Portal_Add(start, end);
 
 	Portal_ClipVisplane(plane, portal);

src/r_portal.h

@@ -11,6 +11,9 @@
 /// \file  r_portal.h
 /// \brief Software renderer portal struct, functions, linked list extern.
 
+#ifndef __R_PORTAL__
+#define __R_PORTAL__
+
 #include "r_data.h"
 #include "r_plane.h" // visplanes
 
@@ -52,3 +55,5 @@ void Portal_AddSkybox	(const visplane_t* plane);
 
 void Portal_ClipRange (portal_t* portal);
 void Portal_ClipApply (const portal_t* portal);
+
+#endif

src/r_things.c

@@ -2185,7 +2185,7 @@ static void R_DrawPrecipitationSprite(vissprite_t *spr)
 
 // R_ClipSprites
 // Clips vissprites without drawing, so that portals can work. -Red
-void R_ClipSprites(void)
+void R_ClipSprites(drawseg_t* dsstart, portal_t* portal)
 {
 	vissprite_t *spr;
 	for (; clippedvissprites < visspritecount; clippedvissprites++)
@@ -2211,7 +2211,7 @@ void R_ClipSprites(void)
 		// and buggy, by going past LEFT end of array:
 
 		//    for (ds = ds_p-1; ds >= drawsegs; ds--)    old buggy code
-		for (ds = ds_p; ds-- > drawsegs ;)
+		for (ds = ds_p; ds-- > dsstart;)
 		{
 			// determine if the drawseg obscures the sprite
 			if (ds->x1 > spr->x2 ||
@@ -2223,34 +2223,37 @@ void R_ClipSprites(void)
 				continue;
 			}
 
-			if (ds->portalpass > 0 && ds->portalpass <= portalrender)
-				continue; // is a portal
+			if (ds->portalpass != 66)
+			{
+				if (ds->portalpass > 0 && ds->portalpass <= portalrender)
+					continue; // is a portal
+
+				if (ds->scale1 > ds->scale2)
+				{
+					lowscale = ds->scale2;
+					scale = ds->scale1;
+				}
+				else
+				{
+					lowscale = ds->scale1;
+					scale = ds->scale2;
+				}
+
+				if (scale < spr->sortscale ||
+					(lowscale < spr->sortscale &&
+					 !R_PointOnSegSide (spr->gx, spr->gy, ds->curline)))
+				{
+					// masked mid texture?
+					/*if (ds->maskedtexturecol)
+						R_RenderMaskedSegRange (ds, r1, r2);*/
+					// seg is behind sprite
+					continue;
+				}
+			}
 
 			r1 = ds->x1 < spr->x1 ? spr->x1 : ds->x1;
 			r2 = ds->x2 > spr->x2 ? spr->x2 : ds->x2;
 
-			if (ds->scale1 > ds->scale2)
-			{
-				lowscale = ds->scale2;
-				scale = ds->scale1;
-			}
-			else
-			{
-				lowscale = ds->scale1;
-				scale = ds->scale2;
-			}
-
-			if (scale < spr->sortscale ||
-			    (lowscale < spr->sortscale &&
-			     !R_PointOnSegSide (spr->gx, spr->gy, ds->curline)))
-			{
-				// masked mid texture?
-				/*if (ds->maskedtexturecol)
-					R_RenderMaskedSegRange (ds, r1, r2);*/
-				// seg is behind sprite
-				continue;
-			}
-
 			// clip this piece of the sprite
 			silhouette = ds->silhouette;
 
@@ -2367,6 +2370,17 @@ void R_ClipSprites(void)
 				//Fab : 26-04-98: was -1, now clips against console bottom
 				spr->cliptop[x] = (INT16)con_clipviewtop;
 		}
+
+		if (portal)
+		{
+			for (x = spr->x1; x <= spr->x2; x++)
+			{
+				if (spr->clipbot[x] > portal->floorclip[x - portal->start])
+					spr->clipbot[x] = portal->floorclip[x - portal->start];
+				if (spr->cliptop[x] < portal->ceilingclip[x - portal->start])
+					spr->cliptop[x] = portal->ceilingclip[x - portal->start];
+			}
+		}
 	}
 }
 
@@ -2444,12 +2458,13 @@ void R_DrawMasked(maskcount_t* masks, UINT8 nummasks)
 		R_CreateDrawNodes(&masks[i], &heads[i], false);
 	}
 
-	for (i = 0; i < nummasks; i++)
-		CONS_Printf("Mask no.%d:\ndrawsegs: %d\n vissprites: %d\n\n", i, masks[i].drawsegs[1] - masks[i].drawsegs[0], masks[i].vissprites[1] - masks[i].vissprites[0]);
+	//for (i = 0; i < nummasks; i++)
+	//	CONS_Printf("Mask no.%d:\ndrawsegs: %d\n vissprites: %d\n\n", i, masks[i].drawsegs[1] - masks[i].drawsegs[0], masks[i].vissprites[1] - masks[i].vissprites[0]);
 
 	for (; nummasks > 0; nummasks--)
 	{
 		viewz = masks[nummasks - 1].viewz;
+
 		R_DrawMaskedList(&heads[nummasks - 1]);
 		R_ClearDrawNodes(&heads[nummasks - 1]);
 	}

src/r_things.h

@@ -16,6 +16,7 @@
 
 #include "sounds.h"
 #include "r_plane.h"
+#include "r_portal.h"
 
 // "Left" and "Right" character symbols for additional rotation functionality
 #define ROT_L ('L' - '0')
@@ -54,7 +55,7 @@ void R_AddSpriteDefs(UINT16 wadnum);
 void R_AddSprites(sector_t *sec, INT32 lightlevel);
 void R_InitSprites(void);
 void R_ClearSprites(void);
-void R_ClipSprites(void);
+void R_ClipSprites(drawseg_t* dsstart, portal_t* portal);
 
 /** Used to count the amount of masked elements
  * per portal to later group them in separate