Make 3D floors cull areas below or above them to reduce overdraw

src/r_main.c

@@ -149,6 +149,8 @@ consvar_t cv_flipcam2 = {"flipcam2", "No", CV_SAVE|CV_CALL|CV_NOINIT, CV_YesNo,
 
 consvar_t cv_shadow = {"shadow", "On", CV_SAVE, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_skybox = {"skybox", "On", CV_SAVE, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
+consvar_t cv_3dfloors = {"3dfloors", "On", 0, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
+consvar_t cv_ffloorclip = {"ffloorclip", "On", 0, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_allowmlook = {"allowmlook", "Yes", CV_NETVAR, CV_YesNo, NULL, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_showhud = {"showhud", "Yes", CV_CALL,  CV_YesNo, R_SetViewSize, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_translucenthud = {"translucenthud", "10", CV_SAVE, translucenthud_cons_t, NULL, 0, NULL, NULL, 0, 0, NULL};
@@ -1590,6 +1592,8 @@ void R_RegisterEngineStuff(void)
 
 	CV_RegisterVar(&cv_shadow);
 	CV_RegisterVar(&cv_skybox);
+	CV_RegisterVar(&cv_3dfloors);
+	CV_RegisterVar(&cv_ffloorclip);
 
 	CV_RegisterVar(&cv_cam_dist);
 	CV_RegisterVar(&cv_cam_still);

src/r_main.h

@@ -103,6 +103,7 @@ extern consvar_t cv_chasecam, cv_chasecam2;
 extern consvar_t cv_flipcam, cv_flipcam2;
 
 extern consvar_t cv_shadow;
+extern consvar_t cv_3dfloors, cv_ffloorclip;
 extern consvar_t cv_translucency;
 extern consvar_t cv_drawdist, cv_drawdist_nights, cv_drawdist_precip;
 extern consvar_t cv_fov;

src/r_segs.c

@@ -688,6 +688,14 @@ static void R_DrawRepeatFlippedMaskedColumn(column_t *col)
 	} while (sprtopscreen < sprbotscreen);
 }
 
+// Returns true if the fake floor will be translucent
+static boolean R_IsFFloorTranslucent(ffloor_t *pfloor)
+{
+	if (pfloor->flags & FF_TRANSLUCENT)
+		return (pfloor->alpha < 243);
+	return false;
+}
+
 //
 // R_RenderThickSideRange
 // Renders all the thick sides in the given range.
@@ -1200,6 +1208,14 @@ static inline void R_ExpandPlaneY(visplane_t *pl, INT32 x, INT16 top, INT16 bott
 	if (pl->bottom[x] < bottom) pl->bottom[x] = bottom;
 }
 
+// R_FFloorCanClip
+//
+// Returns true if a fake floor can clip a column away.
+static boolean R_FFloorCanClip(visffloor_t *floor)
+{
+	return (cv_ffloorclip.value && !R_IsFFloorTranslucent(floor->ffloor) && !floor->polyobj);
+}
+
 //
 // R_RenderSegLoop
 // Draws zero, one, or two textures (and possibly a masked
@@ -1283,6 +1299,8 @@ static void R_RenderSegLoop (void)
 
 		if (numffloors)
 		{
+			INT16 fftop, ffbottom;
+
 			firstseg->frontscale[rw_x] = frontscale[rw_x];
 			top = ceilingclip[rw_x]+1; // PRBoom
 			bottom = floorclip[rw_x]-1; // PRBoom
@@ -1313,8 +1331,23 @@ static void R_RenderSegLoop (void)
 					{
 						if (top_w <= bottom_w)
 						{
-							ffloor[i].plane->top[rw_x] = (INT16)top_w;
+							fftop = (INT16)top_w;
-							ffloor[i].plane->bottom[rw_x] = (INT16)bottom_w;
+							ffbottom = (INT16)bottom_w;
+
+							ffloor[i].plane->top[rw_x] = fftop;
+							ffloor[i].plane->bottom[rw_x] = ffbottom;
+
+							// Lactozilla: Cull part of the column by the 3D floor if it can't be seen
+							// "bottom" is the top pixel of the floor column
+							if (ffbottom >= bottom && R_FFloorCanClip(&ffloor[i]))
+							{
+								floorclip[rw_x] = fftop-1;
+								if (yh > floorclip[rw_x])
+									yh = floorclip[rw_x];
+
+								if (markfloor && floorplane)
+									floorplane->top[rw_x] = bottom;
+							}
 						}
 					}
 				}
@@ -1339,8 +1372,23 @@ static void R_RenderSegLoop (void)
 					{
 						if (top_w <= bottom_w)
 						{
-							ffloor[i].plane->top[rw_x] = (INT16)top_w;
+							fftop = (INT16)top_w;
-							ffloor[i].plane->bottom[rw_x] = (INT16)bottom_w;
+							ffbottom = (INT16)bottom_w;
+
+							ffloor[i].plane->top[rw_x] = fftop;
+							ffloor[i].plane->bottom[rw_x] = ffbottom;
+
+							// Lactozilla: Cull part of the column by the 3D floor if it can't be seen
+							// "top" is the height of the ceiling column
+							if (fftop <= top && R_FFloorCanClip(&ffloor[i]))
+							{
+								ceilingclip[rw_x] = ffbottom+1;
+								if (yl < ceilingclip[rw_x])
+									yl = ceilingclip[rw_x];
+
+								if (markceiling && ceilingplane)
+									ceilingplane->bottom[rw_x] = top;
+							}
 						}
 					}
 				}

src/r_things.c

@@ -2251,7 +2251,7 @@ static void R_CreateDrawNodes(maskcount_t* mask, drawnode_t* head, boolean temps
 	// Add the 3D floors, thicksides, and masked textures...
 	for (ds = drawsegs + mask->drawsegs[1]; ds-- > drawsegs + mask->drawsegs[0];)
 	{
-		if (ds->numthicksides)
+		if (ds->numthicksides && cv_3dfloors.value)
 		{
 			for (i = 0; i < ds->numthicksides; i++)
 			{
@@ -2280,7 +2280,7 @@ static void R_CreateDrawNodes(maskcount_t* mask, drawnode_t* head, boolean temps
 			entry = R_CreateDrawNode(head);
 			entry->seg = ds;
 		}
-		if (ds->numffloorplanes)
+		if (ds->numffloorplanes && cv_3dfloors.value)
 		{
 			for (i = 0; i < ds->numffloorplanes; i++)
 			{