gzdoom-gles/src/swrenderer/scene/r_bsp.cpp

// Emacs style mode select	 -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// DESCRIPTION:
//		BSP traversal, handling of LineSegs for rendering.
//
//-----------------------------------------------------------------------------


#include <stdlib.h>

#include "templates.h"

#include "doomdef.h"

#include "m_bbox.h"

#include "i_system.h"
#include "p_lnspec.h"
#include "p_setup.h"

#include "swrenderer/r_main.h"
#include "swrenderer/drawers/r_draw.h"
#include "swrenderer/plane/r_visibleplane.h"
#include "swrenderer/things/r_particle.h"
#include "swrenderer/segments/r_clipsegment.h"
#include "swrenderer/line/r_wallsetup.h"
#include "r_things.h"
#include "r_3dfloors.h"
#include "r_portal.h"
#include "a_sharedglobal.h"
#include "g_level.h"
#include "p_effect.h"

// State.
#include "doomstat.h"
#include "r_state.h"
#include "r_bsp.h"
#include "v_palette.h"
#include "r_sky.h"
#include "po_man.h"
#include "r_data/colormaps.h"

CVAR (Bool, r_drawflat, false, 0)		// [RH] Don't texture segs?
EXTERN_CVAR(Bool, r_fullbrightignoresectorcolor);

namespace swrenderer
{
	namespace
	{
		subsector_t *InSubsector;
		sector_t *frontsector;

		SWRenderLine render_line;
	}

bool			r_fakingunderwater;

static BYTE		FakeSide;

visplane_t *floorplane;
visplane_t *ceilingplane;

// Clip values are the solid pixel bounding the range.
//	floorclip starts out SCREENHEIGHT and is just outside the range
//	ceilingclip starts out 0 and is just inside the range
//
short floorclip[MAXWIDTH];
short ceilingclip[MAXWIDTH];


//
// killough 3/7/98: Hack floor/ceiling heights for deep water etc.
//
// If player's view height is underneath fake floor, lower the
// drawn ceiling to be just under the floor height, and replace
// the drawn floor and ceiling textures, and light level, with
// the control sector's.
//
// Similar for ceiling, only reflected.
//
// killough 4/11/98, 4/13/98: fix bugs, add 'back' parameter
//

sector_t *R_FakeFlat(sector_t *sec, sector_t *tempsec, int *floorlightlevel, int *ceilinglightlevel, seg_t *backline, int backx1, int backx2, double frontcz1, double frontcz2)
{
	// [RH] allow per-plane lighting
	if (floorlightlevel != NULL)
	{
		*floorlightlevel = sec->GetFloorLight ();
	}

	if (ceilinglightlevel != NULL)
	{
		*ceilinglightlevel = sec->GetCeilingLight ();
	}

	FakeSide = FAKED_Center;

	const sector_t *s = sec->GetHeightSec();
	if (s != NULL)
	{
		sector_t *heightsec = viewsector->heightsec;
		bool underwater = r_fakingunderwater ||
			(heightsec && heightsec->floorplane.PointOnSide(ViewPos) <= 0);
		bool doorunderwater = false;
		int diffTex = (s->MoreFlags & SECF_CLIPFAKEPLANES);

		// Replace sector being drawn with a copy to be hacked
		*tempsec = *sec;

		// Replace floor and ceiling height with control sector's heights.
		if (diffTex)
		{
			if (s->floorplane.CopyPlaneIfValid (&tempsec->floorplane, &sec->ceilingplane))
			{
				tempsec->SetTexture(sector_t::floor, s->GetTexture(sector_t::floor), false);
			}
			else if (s->MoreFlags & SECF_FAKEFLOORONLY)
			{
				if (underwater)
				{
					tempsec->ColorMap = s->ColorMap;
					if (!(s->MoreFlags & SECF_NOFAKELIGHT))
					{
						tempsec->lightlevel = s->lightlevel;

						if (floorlightlevel != NULL)
						{
							*floorlightlevel = s->GetFloorLight ();
						}

						if (ceilinglightlevel != NULL)
						{
							*ceilinglightlevel = s->GetCeilingLight ();
						}
					}
					FakeSide = FAKED_BelowFloor;
					return tempsec;
				}
				return sec;
			}
		}
		else
		{
			tempsec->floorplane = s->floorplane;
		}

		if (!(s->MoreFlags & SECF_FAKEFLOORONLY))
		{
			if (diffTex)
			{
				if (s->ceilingplane.CopyPlaneIfValid (&tempsec->ceilingplane, &sec->floorplane))
				{
					tempsec->SetTexture(sector_t::ceiling, s->GetTexture(sector_t::ceiling), false);
				}
			}
			else
			{
				tempsec->ceilingplane  = s->ceilingplane;
			}
		}

		double refceilz = s->ceilingplane.ZatPoint(ViewPos);
		double orgceilz = sec->ceilingplane.ZatPoint(ViewPos);

#if 1
		// [RH] Allow viewing underwater areas through doors/windows that
		// are underwater but not in a water sector themselves.
		// Only works if you cannot see the top surface of any deep water
		// sectors at the same time.
		if (backline && !r_fakingunderwater && backline->frontsector->heightsec == NULL)
		{
			if (frontcz1 <= s->floorplane.ZatPoint(backline->v1) &&
				frontcz2 <= s->floorplane.ZatPoint(backline->v2))
			{
				// Check that the window is actually visible
				for (int z = backx1; z < backx2; ++z)
				{
					if (floorclip[z] > ceilingclip[z])
					{
						doorunderwater = true;
						r_fakingunderwater = true;
						break;
					}
				}
			}
		}
#endif

		if (underwater || doorunderwater)
		{
			tempsec->floorplane = sec->floorplane;
			tempsec->ceilingplane = s->floorplane;
			tempsec->ceilingplane.FlipVert ();
			tempsec->ceilingplane.ChangeHeight(-1 / 65536.);
			tempsec->ColorMap = s->ColorMap;
		}

		// killough 11/98: prevent sudden light changes from non-water sectors:
		if ((underwater && !backline) || doorunderwater)
		{					// head-below-floor hack
			tempsec->SetTexture(sector_t::floor, diffTex ? sec->GetTexture(sector_t::floor) : s->GetTexture(sector_t::floor), false);
			tempsec->planes[sector_t::floor].xform = s->planes[sector_t::floor].xform;

			tempsec->ceilingplane		= s->floorplane;
			tempsec->ceilingplane.FlipVert ();
			tempsec->ceilingplane.ChangeHeight (-1 / 65536.);
			if (s->GetTexture(sector_t::ceiling) == skyflatnum)
			{
				tempsec->floorplane			= tempsec->ceilingplane;
				tempsec->floorplane.FlipVert ();
				tempsec->floorplane.ChangeHeight (+1 / 65536.);
				tempsec->SetTexture(sector_t::ceiling, tempsec->GetTexture(sector_t::floor), false);
				tempsec->planes[sector_t::ceiling].xform = tempsec->planes[sector_t::floor].xform;
			}
			else
			{
				tempsec->SetTexture(sector_t::ceiling, diffTex ? s->GetTexture(sector_t::floor) : s->GetTexture(sector_t::ceiling), false);
				tempsec->planes[sector_t::ceiling].xform = s->planes[sector_t::ceiling].xform;
			}

			if (!(s->MoreFlags & SECF_NOFAKELIGHT))
			{
				tempsec->lightlevel = s->lightlevel;

				if (floorlightlevel != NULL)
				{
					*floorlightlevel = s->GetFloorLight ();
				}

				if (ceilinglightlevel != NULL)
				{
					*ceilinglightlevel = s->GetCeilingLight ();
				}
			}
			FakeSide = FAKED_BelowFloor;
		}
		else if (heightsec && heightsec->ceilingplane.PointOnSide(ViewPos) <= 0 &&
				 orgceilz > refceilz && !(s->MoreFlags & SECF_FAKEFLOORONLY))
		{	// Above-ceiling hack
			tempsec->ceilingplane		= s->ceilingplane;
			tempsec->floorplane			= s->ceilingplane;
			tempsec->floorplane.FlipVert ();
			tempsec->floorplane.ChangeHeight (+1 / 65536.);
			tempsec->ColorMap			= s->ColorMap;
			tempsec->ColorMap			= s->ColorMap;

			tempsec->SetTexture(sector_t::ceiling, diffTex ? sec->GetTexture(sector_t::ceiling) : s->GetTexture(sector_t::ceiling), false);
			tempsec->SetTexture(sector_t::floor, s->GetTexture(sector_t::ceiling), false);
			tempsec->planes[sector_t::ceiling].xform = tempsec->planes[sector_t::floor].xform = s->planes[sector_t::ceiling].xform;

			if (s->GetTexture(sector_t::floor) != skyflatnum)
			{
				tempsec->ceilingplane	= sec->ceilingplane;
				tempsec->SetTexture(sector_t::floor, s->GetTexture(sector_t::floor), false);
				tempsec->planes[sector_t::floor].xform = s->planes[sector_t::floor].xform;
			}

			if (!(s->MoreFlags & SECF_NOFAKELIGHT))
			{
				tempsec->lightlevel  = s->lightlevel;

				if (floorlightlevel != NULL)
				{
					*floorlightlevel = s->GetFloorLight ();
				}

				if (ceilinglightlevel != NULL)
				{
					*ceilinglightlevel = s->GetCeilingLight ();
				}
			}
			FakeSide = FAKED_AboveCeiling;
		}
		sec = tempsec;					// Use other sector
	}
	return sec;
}



// Checks BSP node/subtree bounding box.
// Returns true if some part of the bbox might be visible.
static bool R_CheckBBox (float *bspcoord)	// killough 1/28/98: static
{
	static const int checkcoord[12][4] =
	{
		{ 3,0,2,1 },
		{ 3,0,2,0 },
		{ 3,1,2,0 },
		{ 0 },
		{ 2,0,2,1 },
		{ 0,0,0,0 },
		{ 3,1,3,0 },
		{ 0 },
		{ 2,0,3,1 },
		{ 2,1,3,1 },
		{ 2,1,3,0 }
	};

	int 				boxx;
	int 				boxy;
	int 				boxpos;

	double	 			x1, y1, x2, y2;
	double				rx1, ry1, rx2, ry2;
	int					sx1, sx2;
	
	// Find the corners of the box
	// that define the edges from current viewpoint.
	if (ViewPos.X <= bspcoord[BOXLEFT])
		boxx = 0;
	else if (ViewPos.X < bspcoord[BOXRIGHT])
		boxx = 1;
	else
		boxx = 2;

	if (ViewPos.Y >= bspcoord[BOXTOP])
		boxy = 0;
	else if (ViewPos.Y > bspcoord[BOXBOTTOM])
		boxy = 1;
	else
		boxy = 2;

	boxpos = (boxy<<2)+boxx;
	if (boxpos == 5)
		return true;

	x1 = bspcoord[checkcoord[boxpos][0]] - ViewPos.X;
	y1 = bspcoord[checkcoord[boxpos][1]] - ViewPos.Y;
	x2 = bspcoord[checkcoord[boxpos][2]] - ViewPos.X;
	y2 = bspcoord[checkcoord[boxpos][3]] - ViewPos.Y;

	// check clip list for an open space

	// Sitting on a line?
	if (y1 * (x1 - x2) + x1 * (y2 - y1) >= -EQUAL_EPSILON)
		return true;

	rx1 = x1 * ViewSin - y1 * ViewCos;
	rx2 = x2 * ViewSin - y2 * ViewCos;
	ry1 = x1 * ViewTanCos + y1 * ViewTanSin;
	ry2 = x2 * ViewTanCos + y2 * ViewTanSin;

	if (MirrorFlags & RF_XFLIP)
	{
		double t = -rx1;
		rx1 = -rx2;
		rx2 = t;
		swapvalues(ry1, ry2);
	}

	if (rx1 >= -ry1)
	{
		if (rx1 > ry1) return false;	// left edge is off the right side
		if (ry1 == 0) return false;
		sx1 = xs_RoundToInt(CenterX + rx1 * CenterX / ry1);
	}
	else
	{
		if (rx2 < -ry2) return false;	// wall is off the left side
		if (rx1 - rx2 - ry2 + ry1 == 0) return false;	// wall does not intersect view volume
		sx1 = 0;
	}

	if (rx2 <= ry2)
	{
		if (rx2 < -ry2) return false;	// right edge is off the left side
		if (ry2 == 0) return false;
		sx2 = xs_RoundToInt(CenterX + rx2 * CenterX / ry2);
	}
	else
	{
		if (rx1 > ry1) return false;	// wall is off the right side
		if (ry2 - ry1 - rx2 + rx1 == 0) return false;	// wall does not intersect view volume
		sx2 = viewwidth;
	}

	// Find the first clippost that touches the source post
	//	(adjacent pixels are touching).

	return R_IsWallSegmentVisible(sx1, sx2);
}


void R_Subsector (subsector_t *sub);
static void R_AddPolyobjs(subsector_t *sub)
{
	if (sub->BSP == NULL || sub->BSP->bDirty)
	{
		sub->BuildPolyBSP();
	}
	if (sub->BSP->Nodes.Size() == 0)
	{
		R_Subsector(&sub->BSP->Subsectors[0]);
	}
	else
	{
		R_RenderBSPNode(&sub->BSP->Nodes.Last());
	}
}

// kg3D - add fake segs, never rendered
void R_FakeDrawLoop(subsector_t *sub)
{
	int 		 count;
	seg_t*		 line;

	count = sub->numlines;
	line = sub->firstline;

	while (count--)
	{
		if ((line->sidedef) && !(line->sidedef->Flags & WALLF_POLYOBJ))
		{
			render_line.Render(line, InSubsector, frontsector, nullptr);
		}
		line++;
	}
}

//
// R_Subsector
// Determine floor/ceiling planes.
// Add sprites of things in sector.
// Draw one or more line segments.
//
void R_Subsector (subsector_t *sub)
{
	int 		 count;
	seg_t*		 line;
	sector_t     tempsec;				// killough 3/7/98: deep water hack
	int          floorlightlevel;		// killough 3/16/98: set floor lightlevel
	int          ceilinglightlevel;		// killough 4/11/98
	bool		 outersubsector;
	int	fll, cll, position;
	FSectorPortal *portal;

	// kg3D - fake floor stuff
	visplane_t *backupfp;
	visplane_t *backupcp;
	//secplane_t templane;
	lightlist_t *light;

	if (InSubsector != NULL)
	{ // InSubsector is not NULL. This means we are rendering from a mini-BSP.
		outersubsector = false;
	}
	else
	{
		outersubsector = true;
		InSubsector = sub;
	}

#ifdef RANGECHECK
	if (outersubsector && sub - subsectors >= (ptrdiff_t)numsubsectors)
		I_Error ("R_Subsector: ss %ti with numss = %i", sub - subsectors, numsubsectors);
#endif

	assert(sub->sector != NULL);

	if (sub->polys)
	{ // Render the polyobjs in the subsector first
		R_AddPolyobjs(sub);
		if (outersubsector)
		{
			InSubsector = NULL;
		}
		return;
	}

	frontsector = sub->sector;
	frontsector->MoreFlags |= SECF_DRAWN;
	count = sub->numlines;
	line = sub->firstline;

	// killough 3/8/98, 4/4/98: Deep water / fake ceiling effect
	frontsector = R_FakeFlat(frontsector, &tempsec, &floorlightlevel, &ceilinglightlevel, nullptr, 0, 0, 0, 0);

	fll = floorlightlevel;
	cll = ceilinglightlevel;

	// [RH] set foggy flag
	foggy = level.fadeto || frontsector->ColorMap->Fade || (level.flags & LEVEL_HASFADETABLE);
	r_actualextralight = foggy ? 0 : extralight << 4;

	// kg3D - fake lights
	if (fixedlightlev < 0 && frontsector->e && frontsector->e->XFloor.lightlist.Size())
	{
		light = P_GetPlaneLight(frontsector, &frontsector->ceilingplane, false);
		basecolormap = light->extra_colormap;
		// If this is the real ceiling, don't discard plane lighting R_FakeFlat()
		// accounted for.
		if (light->p_lightlevel != &frontsector->lightlevel)
		{
			ceilinglightlevel = *light->p_lightlevel;
		}
	}
	else
	{
		basecolormap = (r_fullbrightignoresectorcolor && fixedlightlev >= 0) ? &FullNormalLight : frontsector->ColorMap;
	}

	portal = frontsector->ValidatePortal(sector_t::ceiling);

	ceilingplane = frontsector->ceilingplane.PointOnSide(ViewPos) > 0 ||
		frontsector->GetTexture(sector_t::ceiling) == skyflatnum ||
		portal != NULL ||
		(frontsector->heightsec && 
		 !(frontsector->heightsec->MoreFlags & SECF_IGNOREHEIGHTSEC) &&
		 frontsector->heightsec->GetTexture(sector_t::floor) == skyflatnum) ?
		R_FindPlane(frontsector->ceilingplane,		// killough 3/8/98
					frontsector->GetTexture(sector_t::ceiling),
					ceilinglightlevel + r_actualextralight,				// killough 4/11/98
					frontsector->GetAlpha(sector_t::ceiling),
					!!(frontsector->GetFlags(sector_t::ceiling) & PLANEF_ADDITIVE),
					frontsector->planes[sector_t::ceiling].xform,
					frontsector->sky,
					portal
					) : NULL;

	if (ceilingplane)
		R_AddPlaneLights(ceilingplane, frontsector->lighthead);

	if (fixedlightlev < 0 && frontsector->e && frontsector->e->XFloor.lightlist.Size())
	{
		light = P_GetPlaneLight(frontsector, &frontsector->floorplane, false);
		basecolormap = light->extra_colormap;
		// If this is the real floor, don't discard plane lighting R_FakeFlat()
		// accounted for.
		if (light->p_lightlevel != &frontsector->lightlevel)
		{
			floorlightlevel = *light->p_lightlevel;
		}
	}
	else
	{
		basecolormap = (r_fullbrightignoresectorcolor && fixedlightlev >= 0) ? &FullNormalLight : frontsector->ColorMap;
	}

	// killough 3/7/98: Add (x,y) offsets to flats, add deep water check
	// killough 3/16/98: add floorlightlevel
	// killough 10/98: add support for skies transferred from sidedefs
	portal = frontsector->ValidatePortal(sector_t::floor);

	floorplane = frontsector->floorplane.PointOnSide(ViewPos) > 0 || // killough 3/7/98
		frontsector->GetTexture(sector_t::floor) == skyflatnum ||
		portal != NULL ||
		(frontsector->heightsec &&
		 !(frontsector->heightsec->MoreFlags & SECF_IGNOREHEIGHTSEC) &&
		 frontsector->heightsec->GetTexture(sector_t::ceiling) == skyflatnum) ?
		R_FindPlane(frontsector->floorplane,
					frontsector->GetTexture(sector_t::floor),
					floorlightlevel + r_actualextralight,				// killough 3/16/98
					frontsector->GetAlpha(sector_t::floor),
					!!(frontsector->GetFlags(sector_t::floor) & PLANEF_ADDITIVE),
					frontsector->planes[sector_t::floor].xform,
					frontsector->sky,
					portal
					) : NULL;

	if (floorplane)
		R_AddPlaneLights(floorplane, frontsector->lighthead);

	// kg3D - fake planes rendering
	if (r_3dfloors && frontsector->e && frontsector->e->XFloor.ffloors.Size())
	{
		backupfp = floorplane;
		backupcp = ceilingplane;
		// first check all floors
		for (int i = 0; i < (int)frontsector->e->XFloor.ffloors.Size(); i++)
		{
			fakeFloor = frontsector->e->XFloor.ffloors[i];
			if (!(fakeFloor->flags & FF_EXISTS)) continue;
			if (!fakeFloor->model) continue;
			if (fakeFloor->bottom.plane->isSlope()) continue;
			if (!(fakeFloor->flags & FF_NOSHADE) || (fakeFloor->flags & (FF_RENDERPLANES|FF_RENDERSIDES)))
			{
				R_3D_AddHeight(fakeFloor->top.plane, frontsector);
			}
			if (!(fakeFloor->flags & FF_RENDERPLANES)) continue;
			if (fakeFloor->alpha == 0) continue;
			if (fakeFloor->flags & FF_THISINSIDE && fakeFloor->flags & FF_INVERTSECTOR) continue;
			fakeAlpha = MIN<fixed_t>(Scale(fakeFloor->alpha, OPAQUE, 255), OPAQUE);
			if (fakeFloor->validcount != validcount)
			{
				fakeFloor->validcount = validcount;
				R_3D_NewClip();
			}
			double fakeHeight = fakeFloor->top.plane->ZatPoint(frontsector->centerspot);
			if (fakeHeight < ViewPos.Z &&
				fakeHeight > frontsector->floorplane.ZatPoint(frontsector->centerspot))
			{
				fake3D = FAKE3D_FAKEFLOOR;
				tempsec = *fakeFloor->model;
				tempsec.floorplane = *fakeFloor->top.plane;
				tempsec.ceilingplane = *fakeFloor->bottom.plane;
				if (!(fakeFloor->flags & FF_THISINSIDE) && !(fakeFloor->flags & FF_INVERTSECTOR))
				{
					tempsec.SetTexture(sector_t::floor, tempsec.GetTexture(sector_t::ceiling));
					position = sector_t::ceiling;
				} else position = sector_t::floor;
				frontsector = &tempsec;

				if (fixedlightlev < 0 && sub->sector->e->XFloor.lightlist.Size())
				{
					light = P_GetPlaneLight(sub->sector, &frontsector->floorplane, false);
					basecolormap = light->extra_colormap;
					floorlightlevel = *light->p_lightlevel;
				}

				ceilingplane = NULL;
				floorplane = R_FindPlane(frontsector->floorplane,
					frontsector->GetTexture(sector_t::floor),
					floorlightlevel + r_actualextralight,				// killough 3/16/98
					frontsector->GetAlpha(sector_t::floor),
					!!(fakeFloor->flags & FF_ADDITIVETRANS),
					frontsector->planes[position].xform,
					frontsector->sky,
					NULL);

				if (floorplane)
					R_AddPlaneLights(floorplane, frontsector->lighthead);

				R_FakeDrawLoop(sub);
				fake3D = 0;
				frontsector = sub->sector;
			}
		}
		// and now ceilings
		for (unsigned int i = 0; i < frontsector->e->XFloor.ffloors.Size(); i++)
		{
			fakeFloor = frontsector->e->XFloor.ffloors[i];
			if (!(fakeFloor->flags & FF_EXISTS)) continue;
			if (!fakeFloor->model) continue;
			if (fakeFloor->top.plane->isSlope()) continue;
			if (!(fakeFloor->flags & FF_NOSHADE) || (fakeFloor->flags & (FF_RENDERPLANES|FF_RENDERSIDES)))
			{
				R_3D_AddHeight(fakeFloor->bottom.plane, frontsector);
			}
			if (!(fakeFloor->flags & FF_RENDERPLANES)) continue;
			if (fakeFloor->alpha == 0) continue;
			if (!(fakeFloor->flags & FF_THISINSIDE) && (fakeFloor->flags & (FF_SWIMMABLE|FF_INVERTSECTOR)) == (FF_SWIMMABLE|FF_INVERTSECTOR)) continue;
			fakeAlpha = MIN<fixed_t>(Scale(fakeFloor->alpha, OPAQUE, 255), OPAQUE);

			if (fakeFloor->validcount != validcount)
			{
				fakeFloor->validcount = validcount;
				R_3D_NewClip();
			}
			double fakeHeight = fakeFloor->bottom.plane->ZatPoint(frontsector->centerspot);
			if (fakeHeight > ViewPos.Z &&
				fakeHeight < frontsector->ceilingplane.ZatPoint(frontsector->centerspot))
			{
				fake3D = FAKE3D_FAKECEILING;
				tempsec = *fakeFloor->model;
				tempsec.floorplane = *fakeFloor->top.plane;
				tempsec.ceilingplane = *fakeFloor->bottom.plane;
				if ((!(fakeFloor->flags & FF_THISINSIDE) && !(fakeFloor->flags & FF_INVERTSECTOR)) ||
					(fakeFloor->flags & FF_THISINSIDE && fakeFloor->flags & FF_INVERTSECTOR))
				{
					tempsec.SetTexture(sector_t::ceiling, tempsec.GetTexture(sector_t::floor));
					position = sector_t::floor;
				} else position = sector_t::ceiling;
				frontsector = &tempsec;

				tempsec.ceilingplane.ChangeHeight(-1 / 65536.);
				if (fixedlightlev < 0 && sub->sector->e->XFloor.lightlist.Size())
				{
					light = P_GetPlaneLight(sub->sector, &frontsector->ceilingplane, false);
					basecolormap = light->extra_colormap;
					ceilinglightlevel = *light->p_lightlevel;
				}
				tempsec.ceilingplane.ChangeHeight(1 / 65536.);

				floorplane = NULL;
				ceilingplane = R_FindPlane(frontsector->ceilingplane,		// killough 3/8/98
					frontsector->GetTexture(sector_t::ceiling),
					ceilinglightlevel + r_actualextralight,				// killough 4/11/98
					frontsector->GetAlpha(sector_t::ceiling),
					!!(fakeFloor->flags & FF_ADDITIVETRANS),
					frontsector->planes[position].xform,
					frontsector->sky,
					NULL);

				if (ceilingplane)
					R_AddPlaneLights(ceilingplane, frontsector->lighthead);

				R_FakeDrawLoop(sub);
				fake3D = 0;
				frontsector = sub->sector;
			}
		}
		fakeFloor = NULL;
		floorplane = backupfp;
		ceilingplane = backupcp;
	}

	basecolormap = frontsector->ColorMap;
	floorlightlevel = fll;
	ceilinglightlevel = cll;

	// killough 9/18/98: Fix underwater slowdown, by passing real sector 
	// instead of fake one. Improve sprite lighting by basing sprite
	// lightlevels on floor & ceiling lightlevels in the surrounding area.
	// [RH] Handle sprite lighting like Duke 3D: If the ceiling is a sky, sprites are lit by
	// it, otherwise they are lit by the floor.
	R_AddSprites (sub->sector, frontsector->GetTexture(sector_t::ceiling) == skyflatnum ?
		ceilinglightlevel : floorlightlevel, FakeSide);

	// [RH] Add particles
	if ((unsigned int)(sub - subsectors) < (unsigned int)numsubsectors)
	{ // Only do it for the main BSP.
		int shade = LIGHT2SHADE((floorlightlevel + ceilinglightlevel)/2 + r_actualextralight);
		for (WORD i = ParticlesInSubsec[(unsigned int)(sub-subsectors)]; i != NO_PARTICLE; i = Particles[i].snext)
		{
			R_ProjectParticle (Particles + i, subsectors[sub-subsectors].sector, shade, FakeSide);
		}
	}

	count = sub->numlines;
	line = sub->firstline;

	while (count--)
	{
		if (!outersubsector || line->sidedef == NULL || !(line->sidedef->Flags & WALLF_POLYOBJ))
		{
			// kg3D - fake planes bounding calculation
			if (r_3dfloors && line->backsector && frontsector->e && line->backsector->e->XFloor.ffloors.Size())
			{
				backupfp = floorplane;
				backupcp = ceilingplane;
				floorplane = NULL;
				ceilingplane = NULL;
				for (unsigned int i = 0; i < line->backsector->e->XFloor.ffloors.Size(); i++)
				{
					fakeFloor = line->backsector->e->XFloor.ffloors[i];
					if (!(fakeFloor->flags & FF_EXISTS)) continue;
					if (!(fakeFloor->flags & FF_RENDERPLANES)) continue;
					if (!fakeFloor->model) continue;
					fake3D = FAKE3D_FAKEBACK;
					tempsec = *fakeFloor->model;
					tempsec.floorplane = *fakeFloor->top.plane;
					tempsec.ceilingplane = *fakeFloor->bottom.plane;
					if (fakeFloor->validcount != validcount)
					{
						fakeFloor->validcount = validcount;
						R_3D_NewClip();
					}
					render_line.Render(line, InSubsector, frontsector, &tempsec); // fake
				}
				fakeFloor = NULL;
				fake3D = 0;
				floorplane = backupfp;
				ceilingplane = backupcp;
			}
			render_line.Render(line, InSubsector, frontsector, nullptr); // now real
		}
		line++;
	}
	if (outersubsector)
	{
		InSubsector = NULL;
	}
}

void R_RenderScene()
{
	InSubsector = nullptr;
	R_RenderBSPNode(nodes + numnodes - 1);	// The head node is the last node output.
}

//
// RenderBSPNode
// Renders all subsectors below a given node, traversing subtree recursively.
// Just call with BSP root and -1.
// killough 5/2/98: reformatted, removed tail recursion

void R_RenderBSPNode (void *node)
{
	if (numnodes == 0)
	{
		R_Subsector (subsectors);
		return;
	}
	while (!((size_t)node & 1))  // Keep going until found a subsector
	{
		node_t *bsp = (node_t *)node;

		// Decide which side the view point is on.
		int side = R_PointOnSide (ViewPos, bsp);

		// Recursively divide front space (toward the viewer).
		R_RenderBSPNode (bsp->children[side]);

		// Possibly divide back space (away from the viewer).
		side ^= 1;
		if (!R_CheckBBox (bsp->bbox[side]))
			return;

		node = bsp->children[side];
	}
	R_Subsector ((subsector_t *)((BYTE *)node - 1));
}

}