//-----------------------------------------------------------------------------
//
// Copyright 1993-1996 id Software
// Copyright 1999-2016 Randy Heit
// Copyright 2016 Magnus Norddahl
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see http://www.gnu.org/licenses/
//
//-----------------------------------------------------------------------------
//

#include <stdlib.h>
#include <stddef.h>
#include "templates.h"
#include "engineerrors.h"
#include "doomdef.h"
#include "doomstat.h"
#include "doomdata.h"
#include "p_lnspec.h"
#include "p_setup.h"
#include "r_sky.h"
#include "v_video.h"
#include "m_swap.h"
#include "filesystem.h"
#include "stats.h"
#include "a_sharedglobal.h"
#include "d_net.h"
#include "g_level.h"
#include "g_levellocals.h"
#include "r_wallsetup.h"
#include "v_palette.h"
#include "r_utility.h"
#include "r_data/colormaps.h"
#include "texturemanager.h"
#include "r_memory.h"
#include "swrenderer/scene/r_opaque_pass.h"
#include "swrenderer/scene/r_3dfloors.h"
#include "swrenderer/scene/r_portal.h"
#include "swrenderer/scene/r_light.h"
#include "swrenderer/scene/r_scene.h"
#include "swrenderer/viewport/r_viewport.h"
#include "swrenderer/line/r_line.h"
#include "swrenderer/line/r_walldraw.h"
#include "swrenderer/line/r_wallsetup.h"
#include "swrenderer/drawers/r_draw.h"
#include "swrenderer/segments/r_clipsegment.h"
#include "swrenderer/segments/r_drawsegment.h"
#include "swrenderer/plane/r_visibleplane.h"
#include "swrenderer/plane/r_visibleplanelist.h"
#include "swrenderer/things/r_decal.h"
#include "swrenderer/r_renderthread.h"

CVAR(Bool, r_fogboundary, true, 0)
CVAR(Bool, r_drawmirrors, true, 0)

namespace swrenderer
{
	SWRenderLine::SWRenderLine(RenderThread *thread)
	{
		Thread = thread;
	}

	void SWRenderLine::Render(seg_t *line, subsector_t *subsector, sector_t *sector, sector_t *fakebacksector, VisiblePlane *linefloorplane, VisiblePlane *lineceilingplane, Fake3DOpaque opaque3dfloor)
	{
		mSubsector = subsector;
		mFrontSector = sector;
		mBackSector = fakebacksector;
		mFloorPlane = linefloorplane;
		mCeilingPlane = lineceilingplane;
		mLineSegment = line;
		m3DFloor = opaque3dfloor;

		DVector2 pt1 = line->v1->fPos() - Thread->Viewport->viewpoint.Pos;
		DVector2 pt2 = line->v2->fPos() - Thread->Viewport->viewpoint.Pos;

		// Reject lines not facing viewer
		if (pt1.Y * (pt1.X - pt2.X) + pt1.X * (pt2.Y - pt1.Y) >= 0)
			return;

		if (WallC.Init(Thread, pt1, pt2, line))
			return;

		RenderPortal *renderportal = Thread->Portal.get();
		if (WallC.sx1 >= renderportal->WindowRight || WallC.sx2 <= renderportal->WindowLeft)
			return;

		if (line->linedef == nullptr)
		{
			if (Thread->ClipSegments->Check(WallC.sx1, WallC.sx2))
			{
				mSubsector->flags |= SSECMF_DRAWN;
			}
			return;
		}

		// reject lines that aren't seen from the portal (if any)
		// [ZZ] 10.01.2016: lines inside a skybox shouldn't be clipped, although this imposes some limitations on portals in skyboxes.
		if (!renderportal->CurrentPortalInSkybox && renderportal->CurrentPortal && P_ClipLineToPortal(line->linedef, renderportal->CurrentPortal->dst, Thread->Viewport->viewpoint.Pos))
			return;

		mFrontCeilingZ1 = mFrontSector->ceilingplane.ZatPoint(line->v1);
		mFrontFloorZ1 = mFrontSector->floorplane.ZatPoint(line->v1);
		mFrontCeilingZ2 = mFrontSector->ceilingplane.ZatPoint(line->v2);
		mFrontFloorZ2 = mFrontSector->floorplane.ZatPoint(line->v2);

		Clip3DFloors *clip3d = Thread->Clip3D.get();

		if (m3DFloor.type != Fake3DOpaque::FakeBack)
		{
			mBackSector = line->backsector;
		}

		if (mBackSector)
		{
			// kg3D - its fake, no transfer_heights
			if (m3DFloor.type != Fake3DOpaque::FakeBack)
			{ // killough 3/8/98, 4/4/98: hack for invisible ceilings / deep water
				mBackSector = Thread->OpaquePass->FakeFlat(mBackSector, &tempsec, nullptr, nullptr, mLineSegment, WallC.sx1, WallC.sx2, mFrontCeilingZ1, mFrontCeilingZ2);
			}

			mBackCeilingZ1 = mBackSector->ceilingplane.ZatPoint(line->v1);
			mBackFloorZ1 = mBackSector->floorplane.ZatPoint(line->v1);
			mBackCeilingZ2 = mBackSector->ceilingplane.ZatPoint(line->v2);
			mBackFloorZ2 = mBackSector->floorplane.ZatPoint(line->v2);

			if (m3DFloor.type == Fake3DOpaque::FakeBack)
			{
				if (mFrontFloorZ1 >= mBackFloorZ1 && mFrontFloorZ2 >= mBackFloorZ2)
				{
					m3DFloor.clipBotFront = true;
				}
				if (mFrontCeilingZ1 <= mBackCeilingZ1 && mFrontCeilingZ2 <= mBackCeilingZ2)
				{
					m3DFloor.clipTopFront = true;
				}
			}
		}

		mDoorClosed = IsDoorClosed();

		if (IsInvisibleLine())
		{
			// When using GL nodes, do a clipping test for these lines so we can
			// mark their subsectors as visible for automap texturing.
			if (!(mSubsector->flags & SSECMF_DRAWN))
			{
				if (Thread->ClipSegments->Check(WallC.sx1, WallC.sx2))
				{
					mSubsector->flags |= SSECMF_DRAWN;
				}
			}
			return;
		}

		rw_prepped = false;

		bool visible = Thread->ClipSegments->Clip(WallC.sx1, WallC.sx2, IsSolid(), this);

		if (visible)
		{
			mSubsector->flags |= SSECMF_DRAWN;
		}
	}

	bool SWRenderLine::IsInvisibleLine() const
	{
		// Reject empty lines used for triggers and special events.
		// Identical floor and ceiling on both sides, identical light levels
		// on both sides, and no middle texture.

		if (!mBackSector) return false;

		// Portal
		if (mLineSegment->linedef->isVisualPortal() && mLineSegment->sidedef == mLineSegment->linedef->sidedef[0]) return false;

		// Closed door.
		if (mBackCeilingZ1 <= mFrontFloorZ1 && mBackCeilingZ2 <= mFrontFloorZ2) return false;
		if (mBackFloorZ1 >= mFrontCeilingZ1 && mBackFloorZ2 >= mFrontCeilingZ2) return false;
		if (IsDoorClosed()) return false;

		// Window.
		if (mFrontSector->ceilingplane != mBackSector->ceilingplane || mFrontSector->floorplane != mBackSector->floorplane) return false;
		if (SkyboxCompare(mFrontSector, mBackSector)) return false;

		if (mBackSector->lightlevel != mFrontSector->lightlevel) return false;
		if (mBackSector->GetTexture(sector_t::floor) != mFrontSector->GetTexture(sector_t::floor)) return false;
		if (mBackSector->GetTexture(sector_t::ceiling) != mFrontSector->GetTexture(sector_t::ceiling)) return false;
		if (mLineSegment->sidedef->GetTexture(side_t::mid).isValid()) return false;

		if (mBackSector->planes[sector_t::floor].xform != mFrontSector->planes[sector_t::floor].xform) return false;
		if (mBackSector->planes[sector_t::ceiling].xform != mFrontSector->planes[sector_t::ceiling].xform) return false;

		if (mBackSector->GetPlaneLight(sector_t::floor) != mFrontSector->GetPlaneLight(sector_t::floor)) return false;
		if (mBackSector->GetPlaneLight(sector_t::ceiling) != mFrontSector->GetPlaneLight(sector_t::ceiling)) return false;
		if (mBackSector->GetVisFlags(sector_t::floor) != mFrontSector->GetVisFlags(sector_t::floor)) return false;
		if (mBackSector->GetVisFlags(sector_t::ceiling) != mFrontSector->GetVisFlags(sector_t::ceiling)) return false;

		if (mBackSector->Colormap != mFrontSector->Colormap) return false;

		if (mFrontSector->e && mFrontSector->e->XFloor.lightlist.Size()) return false;
		if (mBackSector->e && mBackSector->e->XFloor.lightlist.Size()) return false;

		return true;
	}

	bool SWRenderLine::IsSolid() const
	{
		// One sided
		if (mBackSector == nullptr) return true;

		// Portal
		if (mLineSegment->linedef->isVisualPortal() && mLineSegment->sidedef == mLineSegment->linedef->sidedef[0]) return true;

		// Closed door
		if (mBackCeilingZ1 <= mFrontFloorZ1 && mBackCeilingZ2 <= mFrontFloorZ2) return true;
		if (mBackFloorZ1 >= mFrontCeilingZ1 && mBackFloorZ2 >= mFrontCeilingZ2) return true;
		if (IsDoorClosed()) return true;

		return false;
	}

	bool SWRenderLine::IsDoorClosed() const
	{
		if (!mBackSector) return false;

		// Portal
		if (mLineSegment->linedef->isVisualPortal() && mLineSegment->sidedef == mLineSegment->linedef->sidedef[0]) return false;

		// Closed door.
		if (mBackCeilingZ1 <= mFrontFloorZ1 && mBackCeilingZ2 <= mFrontFloorZ2) return false;
		if (mBackFloorZ1 >= mFrontCeilingZ1 && mBackFloorZ2 >= mFrontCeilingZ2) return false;

		// properly render skies (consider door "open" if both ceilings are sky)
		if (mBackSector->GetTexture(sector_t::ceiling) == skyflatnum && mFrontSector->GetTexture(sector_t::ceiling) == skyflatnum) return false;

		// if door is closed because back is shut:
		if (!(mBackCeilingZ1 <= mBackFloorZ1 && mBackCeilingZ2 <= mBackFloorZ2)) return false;

		// preserve a kind of transparent door/lift special effect:
		if (((mBackCeilingZ1 >= mFrontCeilingZ1 && mBackCeilingZ2 >= mFrontCeilingZ2) || mLineSegment->sidedef->GetTexture(side_t::top).isValid())
			&& ((mBackFloorZ1 <= mFrontFloorZ1 && mBackFloorZ2 <= mFrontFloorZ2) || mLineSegment->sidedef->GetTexture(side_t::bottom).isValid()))
		{
			// killough 1/18/98 -- This function is used to fix the automap bug which
			// showed lines behind closed doors simply because the door had a dropoff.
			//
			// It assumes that Doom has already ruled out a door being closed because
			// of front-back closure (e.g. front floor is taller than back ceiling).

			// This fixes the automap floor height bug -- killough 1/18/98:
			// killough 4/7/98: optimize: save result in doorclosed for use in r_segs.c
			return true;
		}

		return false;
	}

	bool SWRenderLine::SkyboxCompare(sector_t *frontsector, sector_t *backsector) const
	{
		FSectorPortal *frontc = frontsector->GetPortal(sector_t::ceiling);
		FSectorPortal *frontf = frontsector->GetPortal(sector_t::floor);
		FSectorPortal *backc = backsector->GetPortal(sector_t::ceiling);
		FSectorPortal *backf = backsector->GetPortal(sector_t::floor);

		// return true if any of the planes has a linedef-based portal (unless both sides have the same one.
		// Ideally this should also check thing based portals but the omission of this check had been abused to hell and back for those.
		// (Note: This may require a compatibility option if some maps ran into this for line based portals as well.)
		if (!frontc->MergeAllowed()) return (frontc != backc);
		if (!frontf->MergeAllowed()) return (frontf != backf);
		if (!backc->MergeAllowed()) return true;
		if (!backf->MergeAllowed()) return true;
		return false;
	}

	// A wall segment will be drawn between start and stop pixels (inclusive).
	bool SWRenderLine::RenderWallSegment(int start, int stop)
	{
		if (!rw_prepped)
		{
			rw_prepped = true;
			SetWallVariables();
		}

		side_t *sidedef = mLineSegment->sidedef;

		RenderPortal *renderportal = Thread->Portal.get();
		Clip3DFloors *clip3d = Thread->Clip3D.get();

		DrawSegment *draw_segment = Thread->FrameMemory->NewObject<DrawSegment>();

		// 3D floors code abuses the line render code to update plane clipping
		// lists but doesn't actually draw anything.
		if (m3DFloor.type == Fake3DOpaque::Normal)
			Thread->DrawSegments->Push(draw_segment);

		draw_segment->drawsegclip.CurrentPortalUniq = renderportal->CurrentPortalUniq;
		draw_segment->WallC = WallC;
		draw_segment->x1 = start;
		draw_segment->x2 = stop;
		draw_segment->curline = mLineSegment;
		draw_segment->drawsegclip.SubsectorDepth = Thread->OpaquePass->GetSubsectorDepth(mSubsector->Index());

		bool markportal = ShouldMarkPortal();

		if (markportal)
		{
			draw_segment->drawsegclip.silhouette = SIL_BOTH;
		}
		else if (!mBackSector)
		{
			draw_segment->drawsegclip.SetTopClip(Thread, start, stop, viewheight);
			draw_segment->drawsegclip.SetBottomClip(Thread, start, stop, -1);
			draw_segment->drawsegclip.silhouette = SIL_BOTH;
		}
		else
		{
			// two sided line
			if (mFrontFloorZ1 > mBackFloorZ1 || mFrontFloorZ2 > mBackFloorZ2 || mBackSector->floorplane.PointOnSide(Thread->Viewport->viewpoint.Pos) < 0)
			{
				draw_segment->drawsegclip.silhouette = SIL_BOTTOM;
			}

			if (mFrontCeilingZ1 < mBackCeilingZ1 || mFrontCeilingZ2 < mBackCeilingZ2 || mBackSector->ceilingplane.PointOnSide(Thread->Viewport->viewpoint.Pos) < 0)
			{
				draw_segment->drawsegclip.silhouette |= SIL_TOP;
			}

			// killough 1/17/98: this test is required if the fix
			// for the automap bug (r_bsp.c) is used, or else some
			// sprites will be displayed behind closed doors. That
			// fix prevents lines behind closed doors with dropoffs
			// from being displayed on the automap.
			//
			// killough 4/7/98: make doorclosed external variable

			if (mDoorClosed || (mBackCeilingZ1 <= mFrontFloorZ1 && mBackCeilingZ2 <= mFrontFloorZ2))
			{
				draw_segment->drawsegclip.SetBottomClip(Thread, start, stop, -1);
				draw_segment->drawsegclip.silhouette |= SIL_BOTTOM;
			}
			if (mDoorClosed || (mBackFloorZ1 >= mFrontCeilingZ1 && mBackFloorZ2 >= mFrontCeilingZ2))
			{
				draw_segment->drawsegclip.SetTopClip(Thread, start, stop, viewheight);
				draw_segment->drawsegclip.silhouette |= SIL_TOP;
			}

			if (m3DFloor.type == Fake3DOpaque::Normal)
			{
				if ((mCeilingClipped != ProjectedWallCull::OutsideBelow || !sidedef->GetTexture(side_t::top).isValid()) &&
					(mFloorClipped != ProjectedWallCull::OutsideAbove || !sidedef->GetTexture(side_t::bottom).isValid()) &&
					(WallC.sz1 >= TOO_CLOSE_Z && WallC.sz2 >= TOO_CLOSE_Z))
				{
					if (r_3dfloors)
					{
						if (mBackSector->e && mBackSector->e->XFloor.ffloors.Size()) {
							for (int i = 0; i < (int)mBackSector->e->XFloor.ffloors.Size(); i++) {
								F3DFloor* rover = mBackSector->e->XFloor.ffloors[i];
								if (rover->flags & FF_RENDERSIDES && (!(rover->flags & FF_INVERTSIDES) || rover->flags & FF_ALLSIDES)) {
									draw_segment->SetHas3DFloorBackSectorWalls();
									break;
								}
							}
						}
						if (mFrontSector->e && mFrontSector->e->XFloor.ffloors.Size()) {
							for (int i = 0; i < (int)mFrontSector->e->XFloor.ffloors.Size(); i++) {
								F3DFloor* rover = mFrontSector->e->XFloor.ffloors[i];
								if (rover->flags & FF_RENDERSIDES && (rover->flags & FF_ALLSIDES || rover->flags & FF_INVERTSIDES)) {
									draw_segment->SetHas3DFloorFrontSectorWalls();
									break;
								}
							}
						}
					}

					if (IsFogBoundary(mFrontSector, mBackSector))
						draw_segment->SetHasFogBoundary();

					if (mLineSegment->linedef->alpha > 0.0f && sidedef->GetTexture(side_t::mid).isValid())
					{
						auto pic =  GetPalettedSWTexture(sidedef->GetTexture(side_t::mid), true);
						if (pic)
						{
							draw_segment->SetHasTranslucentMidTexture();
							draw_segment->texcoords.ProjectTranslucent(Thread->Viewport.get(), mFrontSector, mBackSector, mLineSegment, WallC, pic);
							draw_segment->drawsegclip.silhouette |= SIL_TOP | SIL_BOTTOM;
						}
					}

					if (draw_segment->HasFogBoundary() || draw_segment->HasTranslucentMidTexture() || draw_segment->Has3DFloorWalls())
					{
						draw_segment->drawsegclip.SetBackupClip(Thread, start, stop, Thread->OpaquePass->ceilingclip);
						Thread->DrawSegments->PushTranslucent(draw_segment);
					}
				}
			}
		}

		ClipSegmentTopBottom(start, stop);

		MarkCeilingPlane(start, stop);
		MarkFloorPlane(start, stop);
		Mark3DFloors(start, stop);

		if (m3DFloor.type != Fake3DOpaque::Normal)
		{
			return false;
		}

		MarkOpaquePassClip(start, stop);

		bool needcliplists = draw_segment->HasFogBoundary() || draw_segment->HasTranslucentMidTexture() || draw_segment->Has3DFloorWalls();

		if (((draw_segment->drawsegclip.silhouette & SIL_TOP) || needcliplists) && !draw_segment->drawsegclip.sprtopclip)
		{
			draw_segment->drawsegclip.SetTopClip(Thread, start, stop, Thread->OpaquePass->ceilingclip);
		}

		if (((draw_segment->drawsegclip.silhouette & SIL_BOTTOM) || needcliplists) && !draw_segment->drawsegclip.sprbottomclip)
		{
			draw_segment->drawsegclip.SetBottomClip(Thread, start, stop, Thread->OpaquePass->floorclip);
		}

		RenderMiddleTexture(start, stop);
		RenderTopTexture(start, stop);
		RenderBottomTexture(start, stop);

		// [RH] Draw any decals bound to the seg
		// [ZZ] Only if not an active mirror
		if (!markportal)
		{
			RenderDecal::RenderDecals(Thread, draw_segment, mLineSegment, mFrontSector, walltop.ScreenY, wallbottom.ScreenY, false);
		}

		if (markportal)
		{
			Thread->Portal->AddLinePortal(mLineSegment->linedef, draw_segment->x1, draw_segment->x2, draw_segment->drawsegclip.sprtopclip, draw_segment->drawsegclip.sprbottomclip);
		}

		return true;
	}

	bool SWRenderLine::ShouldMarkFloor() const
	{
		if (!mFloorPlane)
			return false;
		
		// deep water check
		if (mFrontSector->GetHeightSec() == nullptr)
		{
			int planeside = mFrontSector->floorplane.PointOnSide(Thread->Viewport->viewpoint.Pos);
			if (mFrontSector->floorplane.fC() < 0)	// 3D floors have the floor backwards
				planeside = -planeside;
			if (planeside <= 0)		// above view plane
				return false;
		}

		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;

		if (sidedef == linedef->sidedef[0] && (linedef->special == Line_Mirror && r_drawmirrors))
		{
			return true;
		}
		else if (mBackSector == nullptr) // single sided line
		{
			return true;
		}
		else // two-sided line
		{
			if (linedef->isVisualPortal()) return true;

			// closed door
			if (mBackCeilingZ1 <= mFrontFloorZ1 && mBackCeilingZ2 <= mFrontFloorZ2) return true;
			if (mBackFloorZ1 >= mFrontCeilingZ1 && mBackFloorZ2 >= mFrontCeilingZ2) return true;

			if (mBackSector->floorplane != mFrontSector->floorplane) return true;
			if (mBackSector->lightlevel != mFrontSector->lightlevel) return true;
			if (mBackSector->GetTexture(sector_t::floor) != mFrontSector->GetTexture(sector_t::floor)) return true;
			if (mBackSector->GetPlaneLight(sector_t::floor) != mFrontSector->GetPlaneLight(sector_t::floor)) return true;

			// Add checks for (x,y) offsets
			if (mBackSector->planes[sector_t::floor].xform != mFrontSector->planes[sector_t::floor].xform) return true;
			if (mBackSector->GetAlpha(sector_t::floor) != mFrontSector->GetAlpha(sector_t::floor)) return true;

			// prevent 2s normals from bleeding through deep water
			if (mFrontSector->heightsec) return true;

			if (mBackSector->GetVisFlags(sector_t::floor) != mFrontSector->GetVisFlags(sector_t::floor)) return true;
			if (mBackSector->Colormap != mFrontSector->Colormap) return true;
			if (mFrontSector->e && mFrontSector->e->XFloor.lightlist.Size()) return true;
			if (mBackSector->e && mBackSector->e->XFloor.lightlist.Size()) return true;

			if (sidedef->GetTexture(side_t::mid).isValid() && ((mFrontSector->Level->ib_compatflags & BCOMPATF_CLIPMIDTEX) || (linedef->flags & (ML_CLIP_MIDTEX | ML_WRAP_MIDTEX)) || sidedef->Flags & (WALLF_CLIP_MIDTEX | WALLF_WRAP_MIDTEX))) return true;

			return false;
		}
	}

	bool SWRenderLine::ShouldMarkCeiling() const
	{
		if (!mCeilingPlane)
			return false;
		
		// deep water check
		if (mFrontSector->GetHeightSec() == nullptr && mFrontSector->GetTexture(sector_t::ceiling) != skyflatnum)
		{
			int planeside = mFrontSector->ceilingplane.PointOnSide(Thread->Viewport->viewpoint.Pos);
			if (mFrontSector->ceilingplane.fC() > 0) // 3D floors have the ceiling backwards
				planeside = -planeside;
			if (planeside <= 0) // below view plane
				return false;
		}

		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;

		if (sidedef == linedef->sidedef[0] && (linedef->special == Line_Mirror && r_drawmirrors))
		{
			return true;
		}
		else if (mBackSector == nullptr) // single sided line
		{
			return true;
		}
		else // two-sided line
		{
			if (linedef->isVisualPortal()) return true;

			// closed door
			if (mBackCeilingZ1 <= mFrontFloorZ1 && mBackCeilingZ2 <= mFrontFloorZ2) return true;
			if (mBackFloorZ1 >= mFrontCeilingZ1 && mBackFloorZ2 >= mFrontCeilingZ2) return true;

			if (mFrontSector->GetTexture(sector_t::ceiling) != skyflatnum || mBackSector->GetTexture(sector_t::ceiling) != skyflatnum)
			{
				if (mBackSector->ceilingplane != mFrontSector->ceilingplane) return true;
				if (mBackSector->lightlevel != mFrontSector->lightlevel) return true;
				if (mBackSector->GetTexture(sector_t::ceiling) != mFrontSector->GetTexture(sector_t::ceiling)) return true;

				// Add checks for (x,y) offsets
				if (mBackSector->planes[sector_t::ceiling].xform != mFrontSector->planes[sector_t::ceiling].xform) return true;
				if (mBackSector->GetAlpha(sector_t::ceiling) != mFrontSector->GetAlpha(sector_t::ceiling)) return true;

				// prevent 2s normals from bleeding through fake ceilings
				if (mFrontSector->heightsec && mFrontSector->GetTexture(sector_t::ceiling) != skyflatnum) return true;

				if (mBackSector->GetPlaneLight(sector_t::ceiling) != mFrontSector->GetPlaneLight(sector_t::ceiling)) return true;
				if (mBackSector->GetFlags(sector_t::ceiling) != mFrontSector->GetFlags(sector_t::ceiling)) return true;

				if (mBackSector->Colormap != mFrontSector->Colormap) return true;
				if (mFrontSector->e && mFrontSector->e->XFloor.lightlist.Size()) return true;
				if (mBackSector->e && mBackSector->e->XFloor.lightlist.Size()) return true;

				if (sidedef->GetTexture(side_t::mid).isValid())
				{
					if (mFrontSector->Level->ib_compatflags & BCOMPATF_CLIPMIDTEX) return true;
					if (linedef->flags & (ML_CLIP_MIDTEX | ML_WRAP_MIDTEX)) return true;
					if (sidedef->Flags & (WALLF_CLIP_MIDTEX | WALLF_WRAP_MIDTEX)) return true;
				}
			}
			return false;
		}
	}

	bool SWRenderLine::ShouldMarkPortal() const
	{
		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;

		if (sidedef == linedef->sidedef[0] && (linedef->special == Line_Mirror && r_drawmirrors))
		{
			return true;
		}
		else
		{
			return linedef->isVisualPortal();
		}
	}
	
	void SWRenderLine::SetWallVariables()
	{
		RenderPortal *renderportal = Thread->Portal.get();

		bool rw_havehigh = false;
		bool rw_havelow = false;
		if (mBackSector)
		{
			// Cannot make these walls solid, because it can result in
			// sprite clipping problems for sprites near the wall
			if (mFrontCeilingZ1 > mBackCeilingZ1 || mFrontCeilingZ2 > mBackCeilingZ2)
			{
				rw_havehigh = true;
				wallupper.Project(Thread->Viewport.get(), mBackSector->ceilingplane, &WallC, mLineSegment, renderportal->MirrorFlags & RF_XFLIP);
			}
			if (mFrontFloorZ1 < mBackFloorZ1 || mFrontFloorZ2 < mBackFloorZ2)
			{
				rw_havelow = true;
				walllower.Project(Thread->Viewport.get(), mBackSector->floorplane, &WallC, mLineSegment, renderportal->MirrorFlags & RF_XFLIP);
			}
		}

		if (mLineSegment->linedef->special == Line_Horizon)
		{
			// Be aware: Line_Horizon does not work properly with sloped planes
			fillshort(walltop.ScreenY + WallC.sx1, WallC.sx2 - WallC.sx1, Thread->Viewport->viewwindow.centery);
			fillshort(wallbottom.ScreenY + WallC.sx1, WallC.sx2 - WallC.sx1, Thread->Viewport->viewwindow.centery);
		}
		else
		{
			mCeilingClipped = walltop.Project(Thread->Viewport.get(), mFrontSector->ceilingplane, &WallC, mLineSegment, renderportal->MirrorFlags & RF_XFLIP);
			mFloorClipped = wallbottom.Project(Thread->Viewport.get(), mFrontSector->floorplane, &WallC, mLineSegment, renderportal->MirrorFlags & RF_XFLIP);
		}

		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;

		// mark the segment as visible for auto map
		if (!Thread->Scene->DontMapLines()) linedef->flags |= ML_MAPPED;

		markfloor = ShouldMarkFloor();
		markceiling = ShouldMarkCeiling();

		SetTextures();

		if (mBackSector && !(sidedef == linedef->sidedef[0] && (linedef->special == Line_Mirror && r_drawmirrors)))
		{
			// skyhack to allow height changes in outdoor areas
			if (mFrontSector->GetTexture(sector_t::ceiling) == skyflatnum &&
				mBackSector->GetTexture(sector_t::ceiling) == skyflatnum)
			{
				if (rw_havehigh)
				{ // front ceiling is above back ceiling
					memcpy(&walltop.ScreenY[WallC.sx1], &wallupper.ScreenY[WallC.sx1], (WallC.sx2 - WallC.sx1) * sizeof(walltop.ScreenY[0]));
					rw_havehigh = false;
				}
				else if (rw_havelow && mFrontSector->ceilingplane != mBackSector->ceilingplane)
				{ // back ceiling is above front ceiling
				  // The check for rw_havelow is not Doom-compliant, but it avoids HoM that
				  // would otherwise occur because there is space made available for this
				  // wall but nothing to draw for it.
				  // Recalculate walltop so that the wall is clipped by the back sector's
				  // ceiling instead of the front sector's ceiling.
					walltop.Project(Thread->Viewport.get(), mBackSector->ceilingplane, &WallC, mLineSegment, Thread->Portal->MirrorFlags & RF_XFLIP);
				}
			}
		}
	}

	void SWRenderLine::SetTextures()
	{
		mTopTexture = nullptr;
		mMiddleTexture = nullptr;
		mBottomTexture = nullptr;

		side_t* sidedef = mLineSegment->sidedef;
		line_t* linedef = mLineSegment->linedef;
		if (sidedef == linedef->sidedef[0] && (linedef->special == Line_Mirror && r_drawmirrors)) return;

		if (!mBackSector)
		{
			SetMiddleTexture();
		}
		else
		{
			if (mFrontCeilingZ1 > mBackCeilingZ1 || mFrontCeilingZ2 > mBackCeilingZ2) SetTopTexture();
			if (mFrontFloorZ1 < mBackFloorZ1 || mFrontFloorZ2 < mBackFloorZ2) SetBottomTexture();
		}
	}

	void SWRenderLine::SetTopTexture()
	{
		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;
		
		// No top texture for skyhack lines
		if (mFrontSector->GetTexture(sector_t::ceiling) == skyflatnum && mBackSector->GetTexture(sector_t::ceiling) == skyflatnum) return;
		
		auto tex = GetPalettedSWTexture(sidedef->GetTexture(side_t::top), true);
		if (!tex) return;
		mTopTexture = tex;
	}
	
	void SWRenderLine::SetMiddleTexture()
	{
		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;
		
		// [RH] Horizon lines do not need to be textured
		if (linedef->isVisualPortal()) return;
		if (linedef->special == Line_Horizon) return;
			
		auto tex = GetPalettedSWTexture(sidedef->GetTexture(side_t::mid), true);
		if (!tex) return;
		mMiddleTexture = tex;
	}
	
	void SWRenderLine::SetBottomTexture()
	{
		side_t *sidedef = mLineSegment->sidedef;
		line_t *linedef = mLineSegment->linedef;
		
		auto tex = GetPalettedSWTexture(sidedef->GetTexture(side_t::bottom), true);
		if (!tex) return;
		mBottomTexture = tex;
	}

	bool SWRenderLine::IsFogBoundary(sector_t *front, sector_t *back) const
	{
		return r_fogboundary && CameraLight::Instance()->FixedColormap() == nullptr && front->Colormap.FadeColor &&
			front->Colormap.FadeColor != back->Colormap.FadeColor &&
			(front->GetTexture(sector_t::ceiling) != skyflatnum || back->GetTexture(sector_t::ceiling) != skyflatnum);
	}
	
	void SWRenderLine::ClipSegmentTopBottom(int x1, int x2)
	{
		// clip wall to the floor and ceiling
		auto ceilingclip = Thread->OpaquePass->ceilingclip;
		auto floorclip = Thread->OpaquePass->floorclip;
		for (int x = x1; x < x2; ++x)
		{
			if (walltop.ScreenY[x] < ceilingclip[x])
			{
				walltop.ScreenY[x] = ceilingclip[x];
			}
			if (wallbottom.ScreenY[x] > floorclip[x])
			{
				wallbottom.ScreenY[x] = floorclip[x];
			}
		}
	}

	void SWRenderLine::MarkCeilingPlane(int x1, int x2)
	{
		// mark ceiling areas
		if (markceiling)
		{
			mCeilingPlane = Thread->PlaneList->GetRange(mCeilingPlane, x1, x2);

			auto ceilingclip = Thread->OpaquePass->ceilingclip;
			auto floorclip = Thread->OpaquePass->floorclip;
			Clip3DFloors *clip3d = Thread->Clip3D.get();

			for (int x = x1; x < x2; ++x)
			{
				short top = (clip3d->fakeFloor && m3DFloor.type == Fake3DOpaque::FakeCeiling) ? clip3d->fakeFloor->ceilingclip[x] : ceilingclip[x];
				short bottom = MIN(walltop.ScreenY[x], floorclip[x]);
				if (top < bottom)
				{
					mCeilingPlane->top[x] = top;
					mCeilingPlane->bottom[x] = bottom;
				}
			}
		}
	}

	void SWRenderLine::MarkFloorPlane(int x1, int x2)
	{
		if (markfloor)
		{
			mFloorPlane = Thread->PlaneList->GetRange(mFloorPlane, x1, x2);

			auto ceilingclip = Thread->OpaquePass->ceilingclip;
			auto floorclip = Thread->OpaquePass->floorclip;
			Clip3DFloors *clip3d = Thread->Clip3D.get();

			for (int x = x1; x < x2; ++x)
			{
				short top = MAX(wallbottom.ScreenY[x], ceilingclip[x]);
				short bottom = (clip3d->fakeFloor && m3DFloor.type == Fake3DOpaque::FakeFloor) ? clip3d->fakeFloor->floorclip[x] : floorclip[x];
				if (top < bottom)
				{
					assert(bottom <= viewheight);
					mFloorPlane->top[x] = top;
					mFloorPlane->bottom[x] = bottom;
				}
			}
		}
	}

	void SWRenderLine::Mark3DFloors(int x1, int x2)
	{
		Clip3DFloors *clip3d = Thread->Clip3D.get();

		// kg3D - fake planes clipping
		if (m3DFloor.type == Fake3DOpaque::FakeBack)
		{
			auto ceilingclip = Thread->OpaquePass->ceilingclip;
			auto floorclip = Thread->OpaquePass->floorclip;

			if (m3DFloor.clipBotFront)
			{
				memcpy(clip3d->fakeFloor->floorclip + x1, wallbottom.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
			else
			{
				for (int x = x1; x < x2; ++x)
				{
					walllower.ScreenY[x] = MIN(MAX(walllower.ScreenY[x], ceilingclip[x]), wallbottom.ScreenY[x]);
				}
				memcpy(clip3d->fakeFloor->floorclip + x1, walllower.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
			if (m3DFloor.clipTopFront)
			{
				memcpy(clip3d->fakeFloor->ceilingclip + x1, walltop.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
			else
			{
				for (int x = x1; x < x2; ++x)
				{
					wallupper.ScreenY[x] = MAX(MIN(wallupper.ScreenY[x], floorclip[x]), walltop.ScreenY[x]);
				}
				memcpy(clip3d->fakeFloor->ceilingclip + x1, wallupper.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
		}
	}

	void SWRenderLine::MarkOpaquePassClip(int x1, int x2)
	{
		auto ceilingclip = Thread->OpaquePass->ceilingclip;
		auto floorclip = Thread->OpaquePass->floorclip;

		if (mMiddleTexture) // one sided line
		{
			fillshort(ceilingclip + x1, x2 - x1, viewheight);
			fillshort(floorclip + x1, x2 - x1, 0xffff);
		}
		else
		{ // two sided line
			if (mTopTexture != nullptr)
			{ // top wall
				for (int x = x1; x < x2; ++x)
				{
					wallupper.ScreenY[x] = MAX(MIN(wallupper.ScreenY[x], floorclip[x]), walltop.ScreenY[x]);
				}
				memcpy(ceilingclip + x1, wallupper.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
			else if (markceiling)
			{ // no top wall
				memcpy(ceilingclip + x1, walltop.ScreenY + x1, (x2 - x1) * sizeof(short));
			}

			if (mBottomTexture != nullptr)
			{ // bottom wall
				for (int x = x1; x < x2; ++x)
				{
					walllower.ScreenY[x] = MIN(MAX(walllower.ScreenY[x], ceilingclip[x]), wallbottom.ScreenY[x]);
				}
				memcpy(floorclip + x1, walllower.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
			else if (markfloor)
			{ // no bottom wall
				memcpy(floorclip + x1, wallbottom.ScreenY + x1, (x2 - x1) * sizeof(short));
			}
		}
	}

	void SWRenderLine::RenderTopTexture(int x1, int x2)
	{
		if (mMiddleTexture) return;
		if (!mTopTexture) return;
		if (!viewactive) return;

		ProjectedWallTexcoords texcoords;
		texcoords.ProjectTop(Thread->Viewport.get(), mFrontSector, mBackSector, mLineSegment, WallC, mTopTexture);

		RenderWallPart renderWallpart(Thread);
		renderWallpart.Render(mFrontSector, mLineSegment, WallC, mTopTexture, x1, x2, walltop.ScreenY, wallupper.ScreenY, texcoords, false, false, OPAQUE);
	}

	void SWRenderLine::RenderMiddleTexture(int x1, int x2)
	{
		if (!mMiddleTexture) return;
		if (!viewactive) return;

		ProjectedWallTexcoords texcoords;
		texcoords.ProjectMid(Thread->Viewport.get(), mFrontSector, mLineSegment, WallC, mMiddleTexture);

		RenderWallPart renderWallpart(Thread);
		renderWallpart.Render(mFrontSector, mLineSegment, WallC, mMiddleTexture, x1, x2, walltop.ScreenY, wallbottom.ScreenY, texcoords, false, false, OPAQUE);
	}

	void SWRenderLine::RenderBottomTexture(int x1, int x2)
	{
		if (mMiddleTexture) return;
		if (!mBottomTexture) return;
		if (!viewactive) return;

		ProjectedWallTexcoords texcoords;
		texcoords.ProjectBottom(Thread->Viewport.get(), mFrontSector, mBackSector, mLineSegment, WallC, mBottomTexture);

		RenderWallPart renderWallpart(Thread);
		renderWallpart.Render(mFrontSector, mLineSegment, WallC, mBottomTexture, x1, x2, walllower.ScreenY, wallbottom.ScreenY, texcoords, false, false, OPAQUE);
	}
}
