/*
Copyright (C) 1997-2001 Id Software, Inc.

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 2
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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// r_rast.c

#include <assert.h>

#include "r_local.h"

#define MAXLEFTCLIPEDGES 100

// !!! if these are changed, they must be changed in asm_draw.h too !!!
#define FULLY_CLIPPED_CACHED 0x80000000
#define FRAMECOUNT_MASK      0x7FFFFFFF

unsigned int    cacheoffset;

int             c_faceclip;                                             // number of faces clipped


clipplane_t     *entity_clipplanes;
clipplane_t     world_clipplanes[16];

medge_t         *r_pedge;

qboolean        r_leftclipped, r_rightclipped;
static qboolean makeleftedge, makerightedge;
qboolean        r_nearzionly;

int             sintable[1280];
int             intsintable[1280];
int             blanktable[1280];               // PGM

mvertex_t       r_leftenter, r_leftexit;
mvertex_t       r_rightenter, r_rightexit;

typedef struct
{
	float u, v;
	int   ceilv;
} evert_t;

int        r_emitted;
float      r_nearzi;
float      r_u1, r_v1, r_lzi1;
int        r_ceilv1;

qboolean   r_lastvertvalid;
int        r_skyframe;

msurface_t *r_skyfaces;
mplane_t   r_skyplanes[6];
mtexinfo_t r_skytexinfo[6];
mvertex_t  *r_skyverts;
medge_t    *r_skyedges;
int        *r_skysurfedges;

// I just copied this data from a box map...
int        skybox_planes[12] = {2, -128, 0, -128, 2, 128, 1, 128, 0, 128, 1, -128};

int        box_surfedges[24] = { 1, 2, 3, 4, -1, 5, 6, 7, 8, 9, -6, 10, -2, -7, -9, 11,
				 12, -3, -11, -8, -12, -10, -5, -4};
int        box_edges[24] = { 1, 2, 2, 3, 3, 4, 4, 1, 1, 5, 5, 6, 6, 2, 7, 8, 8, 6, 5, 7, 8, 3, 7, 4};

int        box_faces[6] = {0, 0, 2, 2, 2, 0};

vec3_t     box_vecs[6][2] = {
	{       {0, -1, 0}, {-1, 0, 0} },
	{ {0, 1, 0}, {0, 0, -1} },
	{       {0, -1, 0}, {1, 0, 0} },
	{ {1, 0, 0}, {0, 0, -1} },
	{ {0, -1, 0}, {0, 0, -1} },
	{ {-1, 0, 0}, {0, 0, -1} }
};

float      box_verts[8][3] = {
	{-1, -1, -1},
	{-1, 1, -1},
	{1, 1, -1},
	{1, -1, -1},
	{-1, -1, 1},
	{-1, 1, 1},
	{1, -1, 1},
	{1, 1, 1}
};

// down, west, up, north, east, south
// {"rt", "bk", "lf", "ft", "up", "dn"};

/*
================
R_EmitEdge
================
*/
static void R_EmitEdge( mvertex_t *pv0, mvertex_t *pv1 )
{
	edge_t *edge, *pcheck;
	int    u_check;
	float  u, u_step;
	vec3_t local, transformed;
	float  *world;
	int    v, v2, ceilv0;
	float  scale, lzi0, u0, v0;
	int    side;

	if( r_lastvertvalid )
	{
		u0 = r_u1;
		v0 = r_v1;
		lzi0 = r_lzi1;
		ceilv0 = r_ceilv1;
	}
	else
	{
		world = &pv0->position[0];

		// transform and project
		VectorSubtract( world, tr.modelorg, local );
		TransformVector( local, transformed );

		if( transformed[2] < NEAR_CLIP )
			transformed[2] = NEAR_CLIP;

		lzi0 = 1.0f / transformed[2];

		// FIXME: build x/yscale into transform?
		scale = xscale * lzi0;
		u0 = ( xcenter + scale * transformed[0] );
		if( u0 < RI.fvrectx_adj )
			u0 = RI.fvrectx_adj;
		if( u0 > RI.fvrectright_adj )
			u0 = RI.fvrectright_adj;

		scale = yscale * lzi0;
		v0 = ( ycenter - scale * transformed[1] );
		if( v0 < RI.fvrecty_adj )
			v0 = RI.fvrecty_adj;
		if( v0 > RI.fvrectbottom_adj )
			v0 = RI.fvrectbottom_adj;

		ceilv0 = (int) ceil( v0 );
	}

	world = &pv1->position[0];

// transform and project
	VectorSubtract( world, tr.modelorg, local );
	TransformVector( local, transformed );

	if( transformed[2] < NEAR_CLIP )
		transformed[2] = NEAR_CLIP;

	r_lzi1 = 1.0f / transformed[2];

	scale = xscale * r_lzi1;
	r_u1 = ( xcenter + scale * transformed[0] );
	if( r_u1 < RI.fvrectx_adj )
		r_u1 = RI.fvrectx_adj;
	if( r_u1 > RI.fvrectright_adj )
		r_u1 = RI.fvrectright_adj;

	scale = yscale * r_lzi1;
	r_v1 = ( ycenter - scale * transformed[1] );
	if( r_v1 < RI.fvrecty_adj )
		r_v1 = RI.fvrecty_adj;
	if( r_v1 > RI.fvrectbottom_adj )
		r_v1 = RI.fvrectbottom_adj;

	if( r_lzi1 > lzi0 )
		lzi0 = r_lzi1;

	if( lzi0 > r_nearzi )   // for mipmap finding
		r_nearzi = lzi0;

// for right edges, all we want is the effect on 1/z
	if( r_nearzionly )
		return;

	r_emitted = 1;

	r_ceilv1 = (int) ceil( r_v1 );


// create the edge
	if( ceilv0 == r_ceilv1 || ceilv0 < 0 )
	{
		// we cache unclipped horizontal edges as fully clipped
		if( cacheoffset != 0x7FFFFFFF )
		{
			cacheoffset = FULLY_CLIPPED_CACHED
				      | ( tr.framecount & FRAMECOUNT_MASK );
		}

		return; // horizontal edge
	}

	side = ceilv0 > r_ceilv1;

	edge = edge_p++;

	edge->owner = r_pedge;

	edge->nearzi = lzi0;

	if( side == 0 )
	{
		// trailing edge (go from p1 to p2)
		v = ceilv0;
		v2 = r_ceilv1 - 1;

		if( v < 0 || v > MAXHEIGHT )
		{
			gEngfuncs.Con_Printf( S_ERROR "trailing edge overflow : %d\n", v );
			return;
		}

		edge->surfs[0] = surface_p - surfaces;
		edge->surfs[1] = 0;

		u_step = (( r_u1 - u0 ) / ( r_v1 - v0 ));
		u = u0 + ((float)v - v0 ) * u_step;
	}
	else
	{
		// leading edge (go from p2 to p1)
		v2 = ceilv0 - 1;
		v = r_ceilv1;

		if( v < 0 || v > MAXHEIGHT )
		{
			gEngfuncs.Con_Printf( S_ERROR "leading edge overflow : %d\n", v );
			return;
		}

		edge->surfs[0] = 0;
		edge->surfs[1] = surface_p - surfaces;

		u_step = (( u0 - r_u1 ) / ( v0 - r_v1 ));
		u = r_u1 + ((float)v - r_v1 ) * u_step;
	}

	edge->u_step = u_step * 0x100000;
	edge->u = u * 0x100000 + 0xFFFFF;

// we need to do this to avoid stepping off the edges if a very nearly
// horizontal edge is less than epsilon above a scan, and numeric error causes
// it to incorrectly extend to the scan, and the extension of the line goes off
// the edge of the screen
// FIXME: is this actually needed?
	/*int r = (gpGlobals->width<<20) + (1<<19) - 1;
	int x = (1<<20) + (1<<19) - 1;
	if (edge->u < x)
		edge->u = x;
	if (edge->u > r)
		edge->u = r;*/
	if( edge->u < RI.vrect_x_adj_shift20 )
		edge->u = RI.vrect_x_adj_shift20;
	if( edge->u > RI.vrectright_adj_shift20 )
		edge->u = RI.vrectright_adj_shift20;


//
// sort the edge in normally
//
	u_check = edge->u;
	if( edge->surfs[0] )
		u_check++; // sort trailers after leaders

	if( !newedges[v] || newedges[v]->u >= u_check )
	{
		edge->next = newedges[v];
		newedges[v] = edge;
	}
	else
	{
		pcheck = newedges[v];
		while( pcheck->next && pcheck->next->u < u_check )
			pcheck = pcheck->next;
		edge->next = pcheck->next;
		pcheck->next = edge;
	}

	edge->nextremove = removeedges[v2];
	removeedges[v2] = edge;
}


/*
================
R_ClipEdge
================
*/
static void R_ClipEdge( mvertex_t *pv0, mvertex_t *pv1, clipplane_t *clip )
{
	float     d0, d1, f;
	mvertex_t clipvert;

	if( clip )
	{
		do
		{
			d0 = DotProduct( pv0->position, clip->normal ) - clip->dist;
			d1 = DotProduct( pv1->position, clip->normal ) - clip->dist;

			if( d0 >= 0 )
			{
				// point 0 is unclipped
				if( d1 >= 0 )
				{
					// both points are unclipped
					continue;
				}

				// only point 1 is clipped

				// we don't cache clipped edges
				cacheoffset = 0x7FFFFFFF;

				f = d0 / ( d0 - d1 );
				clipvert.position[0] = pv0->position[0]
						       + f * ( pv1->position[0] - pv0->position[0] );
				clipvert.position[1] = pv0->position[1]
						       + f * ( pv1->position[1] - pv0->position[1] );
				clipvert.position[2] = pv0->position[2]
						       + f * ( pv1->position[2] - pv0->position[2] );

				if( clip->leftedge )
				{
					r_leftclipped = true;
					r_leftexit = clipvert;
				}
				else if( clip->rightedge )
				{
					r_rightclipped = true;
					r_rightexit = clipvert;
				}

				R_ClipEdge( pv0, &clipvert, clip->next );
				return;
			}
			else
			{
				// point 0 is clipped
				if( d1 < 0 )
				{
					// both points are clipped
					// we do cache fully clipped edges
					if( !r_leftclipped )
						cacheoffset = FULLY_CLIPPED_CACHED
							      | ( tr.framecount & FRAMECOUNT_MASK );
					return;
				}

				// only point 0 is clipped
				r_lastvertvalid = false;

				// we don't cache partially clipped edges
				cacheoffset = 0x7FFFFFFF;

				f = d0 / ( d0 - d1 );
				clipvert.position[0] = pv0->position[0]
						       + f * ( pv1->position[0] - pv0->position[0] );
				clipvert.position[1] = pv0->position[1]
						       + f * ( pv1->position[1] - pv0->position[1] );
				clipvert.position[2] = pv0->position[2]
						       + f * ( pv1->position[2] - pv0->position[2] );

				if( clip->leftedge )
				{
					r_leftclipped = true;
					r_leftenter = clipvert;
				}
				else if( clip->rightedge )
				{
					r_rightclipped = true;
					r_rightenter = clipvert;
				}

				R_ClipEdge( &clipvert, pv1, clip->next );
				return;
			}
		}
		while(( clip = clip->next ) != NULL );
	}

// add the edge
	R_EmitEdge( pv0, pv1 );
}

/*
================
R_EmitCachedEdge
================
*/
static void R_EmitCachedEdge( void )
{
	edge_t *pedge_t;

	pedge_t = (edge_t *)((uintptr_t)r_edges + r_pedge->cachededgeoffset );

	if( !pedge_t->surfs[0] )
		pedge_t->surfs[0] = surface_p - surfaces;
	else
		pedge_t->surfs[1] = surface_p - surfaces;

	if( pedge_t->nearzi > r_nearzi )// for mipmap finding
		r_nearzi = pedge_t->nearzi;

	r_emitted = 1;
}


/*
================
R_RenderFace
================
*/
void R_RenderFace( msurface_t *fa, int clipflags )
{
	int         i, lindex;
	unsigned    mask;
	mplane_t    *pplane;
	float       distinv;
	vec3_t      p_normal;
	medge_t     *pedges, tedge;
	clipplane_t *pclip;

	// translucent surfaces are not drawn by the edge renderer
	if( fa->flags & ( SURF_DRAWTURB | SURF_TRANSPARENT ))
	{
		// fa->nextalphasurface = r_alpha_surfaces;
		// r_alpha_surfaces = fa;
		// return;
	}

	// sky surfaces encountered in the world will cause the
	// environment box surfaces to be emited
	if( fa->flags & SURF_DRAWSKY )
	{
		// R_EmitSkyBox ();
		//	return;
	}

// skip out if no more surfs
	if(( surface_p ) >= surf_max )
	{
		//	r_outofsurfaces++;
		return;
	}

// ditto if not enough edges left, or switch to auxedges if possible
	if(( edge_p + fa->numedges + 4 ) >= edge_max )
	{
		// r_outofedges += fa->numedges;
		return;
	}

	c_faceclip++;

// set up clip planes
	pclip = NULL;

	for( i = 3, mask = 0x08; i >= 0; i--, mask >>= 1 )
	{
		if( clipflags & mask )
		{
			qfrustum.view_clipplanes[i].next = pclip;
			pclip = &qfrustum.view_clipplanes[i];
		}
	}

// push the edges through
	r_emitted = 0;
	r_nearzi = 0;
	r_nearzionly = false;
	makeleftedge = makerightedge = false;
	pedges = RI.currentmodel->edges;
	r_lastvertvalid = false;

	for( i = 0; i < fa->numedges; i++ )
	{
		lindex = RI.currentmodel->surfedges[fa->firstedge + i];

		if( lindex > 0 )
		{
			r_pedge = &pedges[lindex];

			// if the edge is cached, we can just reuse the edge
			if( !insubmodel )
			{
				if( r_pedge->cachededgeoffset & FULLY_CLIPPED_CACHED )
				{
					if(( r_pedge->cachededgeoffset & FRAMECOUNT_MASK )
					   == tr.framecount )
					{
						r_lastvertvalid = false;
						continue;
					}
				}
				else
				{
					if((((uintptr_t)edge_p - (uintptr_t)r_edges )
					    > r_pedge->cachededgeoffset )
					   && (((edge_t *)((uintptr_t)r_edges
							   + r_pedge->cachededgeoffset ))->owner == r_pedge ))
					{
						R_EmitCachedEdge();
						r_lastvertvalid = false;
						continue;
					}
				}
			}

			// assume it's cacheable
			cacheoffset = (byte *)edge_p - (byte *)r_edges;
			r_leftclipped = r_rightclipped = false;
			R_ClipEdge( &r_pcurrentvertbase[r_pedge->v[0]],
				    &r_pcurrentvertbase[r_pedge->v[1]],
				    pclip );
			r_pedge->cachededgeoffset = cacheoffset;

			if( r_leftclipped )
				makeleftedge = true;
			if( r_rightclipped )
				makerightedge = true;
			r_lastvertvalid = true;
		}
		else
		{
			lindex = -lindex;
			r_pedge = &pedges[lindex];
			// if the edge is cached, we can just reuse the edge
			if( !insubmodel )
			{
				if( r_pedge->cachededgeoffset & FULLY_CLIPPED_CACHED )
				{
					if(( r_pedge->cachededgeoffset & FRAMECOUNT_MASK )
					   == tr.framecount )
					{
						r_lastvertvalid = false;
						continue;
					}
				}
				else
				{
					// it's cached if the cached edge is valid and is owned
					// by this medge_t
					if((((uintptr_t)edge_p - (uintptr_t)r_edges )
					    > r_pedge->cachededgeoffset )
					   && (((edge_t *)((uintptr_t)r_edges
							   + r_pedge->cachededgeoffset ))->owner == r_pedge ))
					{
						R_EmitCachedEdge();
						r_lastvertvalid = false;
						continue;
					}
				}
			}

			// assume it's cacheable
			cacheoffset = (byte *)edge_p - (byte *)r_edges;
			r_leftclipped = r_rightclipped = false;
			R_ClipEdge( &r_pcurrentvertbase[r_pedge->v[1]],
				    &r_pcurrentvertbase[r_pedge->v[0]],
				    pclip );
			r_pedge->cachededgeoffset = cacheoffset;

			if( r_leftclipped )
				makeleftedge = true;
			if( r_rightclipped )
				makerightedge = true;
			r_lastvertvalid = true;
		}
	}

// if there was a clip off the left edge, add that edge too
// FIXME: faster to do in screen space?
// FIXME: share clipped edges?
	if( makeleftedge )
	{
		r_pedge = &tedge;
		r_lastvertvalid = false;
		R_ClipEdge( &r_leftexit, &r_leftenter, pclip->next );
	}

// if there was a clip off the right edge, get the right r_nearzi
	if( makerightedge )
	{
		r_pedge = &tedge;
		r_lastvertvalid = false;
		r_nearzionly = true;
		R_ClipEdge( &r_rightexit, &r_rightenter, qfrustum.view_clipplanes[1].next );
	}

// if no edges made it out, return without posting the surface
	if( !r_emitted )
		return;

//	r_polycount++;

	surface_p->msurf = fa;
	surface_p->nearzi = r_nearzi;
	surface_p->flags = fa->flags;
	surface_p->insubmodel = insubmodel;
	surface_p->spanstate = 0;
	surface_p->entity = RI.currententity;
	surface_p->key = r_currentkey++;
	surface_p->spans = NULL;

	pplane = fa->plane;
// FIXME: cache this?
	TransformVector( pplane->normal, p_normal );
// FIXME: cache this?
	distinv = 1.0f / ( pplane->dist - DotProduct( tr.modelorg, pplane->normal ));

	surface_p->d_zistepu = p_normal[0] * xscaleinv * distinv;
	surface_p->d_zistepv = -p_normal[1] * yscaleinv * distinv;
	surface_p->d_ziorigin = p_normal[2] * distinv
				- xcenter * surface_p->d_zistepu
				- ycenter * surface_p->d_zistepv;

	surface_p++;
}


/*
================
R_RenderBmodelFace
================
*/
void R_RenderBmodelFace( bedge_t *pedges, msurface_t *psurf )
{
	int         i;
	unsigned    mask;
	mplane_t    *pplane;
	float       distinv;
	vec3_t      p_normal;
	medge_t     tedge;
	clipplane_t *pclip;

	/*if (psurf->texinfo->flags & (SURF_TRANS33|SURF_TRANS66))
	{
		psurf->nextalphasurface = r_alpha_surfaces;
		r_alpha_surfaces = psurf;
		return;
	}*/

// skip out if no more surfs
	if( surface_p >= surf_max )
	{
		// r_outofsurfaces++;
		return;
	}

// ditto if not enough edges left, or switch to auxedges if possible
	if(( edge_p + psurf->numedges + 4 ) >= edge_max )
	{
		// r_outofedges += psurf->numedges;
		return;
	}

	c_faceclip++;

// this is a dummy to give the caching mechanism someplace to write to
	r_pedge = &tedge;

// set up clip planes
	pclip = NULL;

	for( i = 3, mask = 0x08; i >= 0; i--, mask >>= 1 )
	{
		if( r_clipflags & mask )
		{
			qfrustum.view_clipplanes[i].next = pclip;
			pclip = &qfrustum.view_clipplanes[i];
		}
	}

// push the edges through
	r_emitted = 0;
	r_nearzi = 0;
	r_nearzionly = false;
	makeleftedge = makerightedge = false;
// FIXME: keep clipped bmodel edges in clockwise order so last vertex caching
// can be used?
	r_lastvertvalid = false;

	for( ; pedges; pedges = pedges->pnext )
	{
		r_leftclipped = r_rightclipped = false;
		R_ClipEdge( pedges->v[0], pedges->v[1], pclip );

		if( r_leftclipped )
			makeleftedge = true;
		if( r_rightclipped )
			makerightedge = true;
	}

// if there was a clip off the left edge, add that edge too
// FIXME: faster to do in screen space?
// FIXME: share clipped edges?
	if( makeleftedge )
	{
		r_pedge = &tedge;
		R_ClipEdge( &r_leftexit, &r_leftenter, pclip->next );
	}

// if there was a clip off the right edge, get the right r_nearzi
	if( makerightedge )
	{
		r_pedge = &tedge;
		r_nearzionly = true;
		R_ClipEdge( &r_rightexit, &r_rightenter, qfrustum.view_clipplanes[1].next );
	}

// if no edges made it out, return without posting the surface
	if( !r_emitted )
		return;

	// r_polycount++;

	surface_p->msurf = psurf;
	surface_p->nearzi = r_nearzi;
	surface_p->flags = psurf->flags;
	surface_p->insubmodel = true;
	surface_p->spanstate = 0;
	surface_p->entity = RI.currententity;
	surface_p->key = r_currentbkey;
	surface_p->spans = NULL;

	pplane = psurf->plane;
// FIXME: cache this?
	TransformVector( pplane->normal, p_normal );
// FIXME: cache this?
	distinv = 1.0f / ( pplane->dist - DotProduct( tr.modelorg, pplane->normal ));

	surface_p->d_zistepu = p_normal[0] * xscaleinv * distinv;
	surface_p->d_zistepv = -p_normal[1] * yscaleinv * distinv;
	surface_p->d_ziorigin = p_normal[2] * distinv
				- xcenter * surface_p->d_zistepu
				- ycenter * surface_p->d_zistepv;

	surface_p++;
}