/*
** gl_sky.cpp
** Sky preparation code.
**
**---------------------------------------------------------------------------
** Copyright 2002-2005 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
** 4. When not used as part of GZDoom or a GZDoom derivative, this code will be
**    covered by the terms of the GNU Lesser General Public License as published
**    by the Free Software Foundation; either version 2.1 of the License, or (at
**    your option) any later version.
** 5. Full disclosure of the entire project's source code, except for third
**    party libraries is mandatory. (NOTE: This clause is non-negotiable!)
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/

#include "gl/system/gl_system.h"
#include "a_sharedglobal.h"
#include "g_level.h"
#include "r_sky.h"
#include "r_state.h"
#include "r_utility.h"
#include "doomdata.h"
#include "gl/gl_functions.h"

#include "gl/data/gl_data.h"
#include "gl/renderer/gl_lightdata.h"
#include "gl/scene/gl_drawinfo.h"
#include "gl/scene/gl_portal.h"
#include "gl/textures/gl_material.h"
#include "gl/utility/gl_convert.h"

CVAR(Bool,gl_noskyboxes, false, 0)
extern int skyfog;

enum
{
	NoSkyDraw = 89
};


//==========================================================================
//
//  Calculate sky texture
//
//==========================================================================
void GLWall::SkyPlane(sector_t *sector, int plane, bool allowreflect)
{
	FPortal *portal = sector->portals[plane];
	if (portal != NULL)
	{
		if (GLPortal::instack[1-plane]) return;
		type=RENDERWALL_SECTORSTACK;
		this->portal = portal;
	}
	else if (sector->GetTexture(plane)==skyflatnum)
	{
		GLSkyInfo skyinfo;
		ASkyViewpoint * skyboxx = plane == sector_t::floor? sector->FloorSkyBox : sector->CeilingSkyBox;
		if (skyboxx == NULL) skyboxx = level.DefaultSkybox;

		// JUSTHIT is used as an indicator that a skybox is in use.
		// This is to avoid recursion

		if (!gl_noskyboxes && skyboxx && GLRenderer->mViewActor!=skyboxx && !(skyboxx->flags&MF_JUSTHIT))
		{
			type=RENDERWALL_SKYBOX;
			skybox=skyboxx;
		}
		else
		{
			int sky1 = sector->sky;
			memset(&skyinfo, 0, sizeof(skyinfo));
			if ((sky1 & PL_SKYFLAT) && (sky1 & (PL_SKYFLAT-1)))
			{
				const line_t *l = &lines[(sky1&(PL_SKYFLAT-1))-1];
				const side_t *s = l->sidedef[0];
				int pos;
				
				if (level.flags & LEVEL_SWAPSKIES && s->GetTexture(side_t::bottom).isValid())
				{
					pos = side_t::bottom;
				}
				else
				{
					pos = side_t::top;
				}

				FTextureID texno = s->GetTexture(pos);
				skyinfo.texture[0] = FMaterial::ValidateTexture(texno, true);
				if (!skyinfo.texture[0] || skyinfo.texture[0]->tex->UseType == FTexture::TEX_Null) goto normalsky;
				skyinfo.skytexno1 = texno;
				skyinfo.x_offset[0] = ANGLE_TO_FLOAT(s->GetTextureXOffset(pos));
				skyinfo.y_offset = FIXED2FLOAT(s->GetTextureYOffset(pos));
				skyinfo.mirrored = !l->args[2];
			}
			else
			{
			normalsky:
				if (level.flags&LEVEL_DOUBLESKY)
				{
					skyinfo.texture[1]=FMaterial::ValidateTexture(sky1texture, true);
					skyinfo.x_offset[1] = GLRenderer->mSky1Pos;
					skyinfo.doublesky = true;
				}
				
				if ((level.flags&LEVEL_SWAPSKIES || (sky1==PL_SKYFLAT) || (level.flags&LEVEL_DOUBLESKY)) &&
					sky2texture!=sky1texture)	// If both skies are equal use the scroll offset of the first!
				{
					skyinfo.texture[0]=FMaterial::ValidateTexture(sky2texture, true);
					skyinfo.skytexno1=sky2texture;
					skyinfo.sky2 = true;
					skyinfo.x_offset[0] = GLRenderer->mSky2Pos;
				}
				else
				{
					skyinfo.texture[0]=FMaterial::ValidateTexture(sky1texture, true);
					skyinfo.skytexno1=sky1texture;
					skyinfo.x_offset[0] = GLRenderer->mSky1Pos;
				}
			}
			if (skyfog>0) 
			{
				skyinfo.fadecolor=Colormap.FadeColor;
				skyinfo.fadecolor.a=0;
			}
			else skyinfo.fadecolor=0;

			type=RENDERWALL_SKY;
			sky=UniqueSkies.Get(&skyinfo);
		}
	}
	else if (allowreflect && sector->GetReflect(plane) > 0)
	{
		if ((plane == sector_t::ceiling && viewz > sector->ceilingplane.d) ||
			(plane == sector_t::floor && viewz < -sector->floorplane.d)) return;
		type=RENDERWALL_PLANEMIRROR;
		planemirror = plane == sector_t::ceiling? &sector->ceilingplane : &sector->floorplane;
	}
	else return;
	PutWall(0);
}


//==========================================================================
//
//  Skies on one sided walls
//
//==========================================================================

void GLWall::SkyNormal(sector_t * fs,vertex_t * v1,vertex_t * v2)
{
	ztop[0]=ztop[1]=32768.0f;
	zbottom[0]=zceil[0];
	zbottom[1]=zceil[1];
	SkyPlane(fs, sector_t::ceiling, true);

	ztop[0]=zfloor[0];
	ztop[1]=zfloor[1];
	zbottom[0]=zbottom[1]=-32768.0f;
	SkyPlane(fs, sector_t::floor, true);
}

//==========================================================================
//
//  Upper Skies on two sided walls
//
//==========================================================================

void GLWall::SkyTop(seg_t * seg,sector_t * fs,sector_t * bs,vertex_t * v1,vertex_t * v2)
{
	if (fs->GetTexture(sector_t::ceiling)==skyflatnum)
	{
		if ((bs->special&0xff) == NoSkyDraw) return;
		if (bs->GetTexture(sector_t::ceiling)==skyflatnum) 
		{
			// if the back sector is closed the sky must be drawn!
			if (bs->ceilingplane.ZatPoint(v1) > bs->floorplane.ZatPoint(v1) ||
				bs->ceilingplane.ZatPoint(v2) > bs->floorplane.ZatPoint(v2) || bs->transdoor)
					return;

			// one more check for some ugly transparent door hacks
			if (bs->floorplane.a==0 && bs->floorplane.b==0 && fs->floorplane.a==0 && fs->floorplane.b==0)
			{
				if (bs->GetPlaneTexZ(sector_t::floor)==fs->GetPlaneTexZ(sector_t::floor)+FRACUNIT)
				{
					FTexture * tex = TexMan(seg->sidedef->GetTexture(side_t::bottom));
					if (!tex || tex->UseType==FTexture::TEX_Null) return;

					// very, very, very ugly special case (See Icarus MAP14)
					// It is VERY important that this is only done for a floor height difference of 1
					// or it will cause glitches elsewhere.
					tex = TexMan(seg->sidedef->GetTexture(side_t::mid));
					if (tex != NULL && !(seg->linedef->flags & ML_DONTPEGTOP) &&
						seg->sidedef->GetTextureYOffset(side_t::mid) > 0)
					{
						ztop[0]=ztop[1]=32768.0f;
						zbottom[0]=zbottom[1]= 
							FIXED2FLOAT(bs->ceilingplane.ZatPoint(v2) + seg->sidedef->GetTextureYOffset(side_t::mid));
						SkyPlane(fs, sector_t::ceiling, false);
						return;
					}
				}
			}
		}

		ztop[0]=ztop[1]=32768.0f;

		FTexture * tex = TexMan(seg->sidedef->GetTexture(side_t::top));
		if (bs->GetTexture(sector_t::ceiling) != skyflatnum)

		{
			zbottom[0]=zceil[0];
			zbottom[1]=zceil[1];
		}
		else
		{
			zbottom[0]=FIXED2FLOAT(bs->ceilingplane.ZatPoint(v1));
			zbottom[1]=FIXED2FLOAT(bs->ceilingplane.ZatPoint(v2));
			flags|=GLWF_SKYHACK;	// mid textures on such lines need special treatment!
		}
	}
	else 
	{
		FPortal *pfront = fs->portals[sector_t::ceiling];
		FPortal *pback = bs->portals[sector_t::ceiling];
		float frontreflect = fs->GetReflect(sector_t::ceiling);
		if (frontreflect > 0)
		{
			float backreflect = bs->GetReflect(sector_t::ceiling);
			if (backreflect > 0 && bs->ceilingplane.d == fs->ceilingplane.d)
			{
				// Don't add intra-portal line to the portal.
				return;
			}
		}
		else if (pfront == NULL || pfront == pback)
		{
			return;
		}

		// stacked sectors
		fixed_t fsc1=fs->ceilingplane.ZatPoint(v1);
		fixed_t fsc2=fs->ceilingplane.ZatPoint(v2);

		ztop[0]=ztop[1]=32768.0f;
		zbottom[0]=FIXED2FLOAT(fsc1);
		zbottom[1]=FIXED2FLOAT(fsc2);
	}

	SkyPlane(fs, sector_t::ceiling, true);
}


//==========================================================================
//
//  Lower Skies on two sided walls
//
//==========================================================================

void GLWall::SkyBottom(seg_t * seg,sector_t * fs,sector_t * bs,vertex_t * v1,vertex_t * v2)
{
	if (fs->GetTexture(sector_t::floor)==skyflatnum)
	{
		if ((bs->special&0xff) == NoSkyDraw) return;
		FTexture * tex = TexMan(seg->sidedef->GetTexture(side_t::bottom));
		
		// For lower skies the normal logic only applies to walls with no lower texture!
		if (tex->UseType==FTexture::TEX_Null)
		{
			if (bs->GetTexture(sector_t::floor)==skyflatnum)
			{
				// if the back sector is closed the sky must be drawn!
				if (bs->ceilingplane.ZatPoint(v1) > bs->floorplane.ZatPoint(v1) ||
					bs->ceilingplane.ZatPoint(v2) > bs->floorplane.ZatPoint(v2))
						return;

			}
			else
			{
				// Special hack for Vrack2b
				if (bs->floorplane.ZatPoint(FIXED2FLOAT(viewx), FIXED2FLOAT(viewy)) > FIXED2FLOAT(viewz)) return;
			}
		}
		zbottom[0]=zbottom[1]=-32768.0f;

		if ((tex && tex->UseType!=FTexture::TEX_Null) || bs->GetTexture(sector_t::floor)!=skyflatnum)
		{
			ztop[0]=zfloor[0];
			ztop[1]=zfloor[1];
		}
		else
		{
			ztop[0]=FIXED2FLOAT(bs->floorplane.ZatPoint(v1));
			ztop[1]=FIXED2FLOAT(bs->floorplane.ZatPoint(v2));
			flags|=GLWF_SKYHACK;	// mid textures on such lines need special treatment!
		}
	}
	else 
	{
		FPortal *pfront = fs->portals[sector_t::floor];
		FPortal *pback = bs->portals[sector_t::floor];
		float frontreflect = fs->GetReflect(sector_t::floor);
		if (frontreflect > 0)
		{
			float backreflect = bs->GetReflect(sector_t::floor);
			if (backreflect > 0 && bs->floorplane.d == fs->floorplane.d)
			{
				// Don't add intra-portal line to the portal.
				return;
			}
		}
		else if (pfront == NULL || pfront == pback)
		{
			return;
		}

		// stacked sectors
		fixed_t fsc1=fs->floorplane.ZatPoint(v1);
		fixed_t fsc2=fs->floorplane.ZatPoint(v2);

		zbottom[0]=zbottom[1]=-32768.0f;
		ztop[0]=FIXED2FLOAT(fsc1);
		ztop[1]=FIXED2FLOAT(fsc2);
	}

	SkyPlane(fs, sector_t::floor, true);
}