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/*

Copyright (C) 1996-1997 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_draw.c

#include "quakedef.h"

#include "r_local.h"

#include "d_local.h"	// FIXME: shouldn't need to include this

#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

zpointdesc_t	r_zpointdesc;

polydesc_t		r_polydesc;

clipplane_t	*entity_clipplanes;

clipplane_t	view_clipplanes[4];

clipplane_t	world_clipplanes[16];

medge_t			*r_pedge;

qboolean		r_leftclipped, r_rightclipped;

static qboolean	makeleftedge, makerightedge;

qboolean		r_nearzionly;

int		sintable[SIN_BUFFER_SIZE];

int		intsintable[SIN_BUFFER_SIZE];

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;

#if	!id386

/*

================

R_EmitEdge

================

*/

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, modelorg, local);

		TransformVector (local, transformed);

		if (transformed[2] < NEAR_CLIP)

			transformed[2] = NEAR_CLIP;

		lzi0 = 1.0 / transformed[2];

	// FIXME: build x/yscale into transform?

		scale = xscale * lzi0;

		u0 = (xcenter + scale*transformed[0]);

		if (u0 < r_refdef.fvrectx_adj)

			u0 = r_refdef.fvrectx_adj;

		if (u0 > r_refdef.fvrectright_adj)

			u0 = r_refdef.fvrectright_adj;

		scale = yscale * lzi0;

		v0 = (ycenter - scale*transformed[1]);

		if (v0 < r_refdef.fvrecty_adj)

			v0 = r_refdef.fvrecty_adj;

		if (v0 > r_refdef.fvrectbottom_adj)

			v0 = r_refdef.fvrectbottom_adj;

		ceilv0 = (int) ceil(v0);

	}

	world = &pv1->position[0];

// transform and project

	VectorSubtract (world, modelorg, local);

	TransformVector (local, transformed);

	if (transformed[2] < NEAR_CLIP)

		transformed[2] = NEAR_CLIP;

	r_lzi1 = 1.0 / transformed[2];

	scale = xscale * r_lzi1;

	r_u1 = (xcenter + scale*transformed[0]);

	if (r_u1 < r_refdef.fvrectx_adj)

		r_u1 = r_refdef.fvrectx_adj;

	if (r_u1 > r_refdef.fvrectright_adj)

		r_u1 = r_refdef.fvrectright_adj;

	scale = yscale * r_lzi1;

	r_v1 = (ycenter - scale*transformed[1]);

	if (r_v1 < r_refdef.fvrecty_adj)

		r_v1 = r_refdef.fvrecty_adj;

	if (r_v1 > r_refdef.fvrectbottom_adj)

		r_v1 = r_refdef.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)

	{

	// we cache unclipped horizontal edges as fully clipped

		if (cacheoffset != 0x7FFFFFFF)

		{

			cacheoffset = FULLY_CLIPPED_CACHED |

					(r_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;

		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;

		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?

	if (edge->u < r_refdef.vrect_x_adj_shift20)

		edge->u = r_refdef.vrect_x_adj_shift20;

	if (edge->u > r_refdef.vrectright_adj_shift20)

		edge->u = r_refdef.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

================

*/

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 |

								(r_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);

}

#endif	// !id386

/*

================

R_EmitCachedEdge

================

*/

void R_EmitCachedEdge (void)

{

	edge_t		*pedge_t;

	pedge_t = (edge_t *)((unsigned long)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;

// 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)

		{

			view_clipplanes[i].next = pclip;

			pclip = &view_clipplanes[i];

		}

	}

// push the edges through

	r_emitted = 0;

	r_nearzi = 0;

	r_nearzionly = false;

	makeleftedge = makerightedge = false;

	pedges = currententity->model->edges;

	r_lastvertvalid = false;

	for (i=0 ; inumedges ; i++)

	{

		lindex = currententity->model->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) ==

						r_framecount)

					{

						r_lastvertvalid = false;

						continue;

					}

				}

				else

				{

					if ((((unsigned long)edge_p - (unsigned long)r_edges) >

						 r_pedge->cachededgeoffset) &&

						(((edge_t *)((unsigned long)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) ==

						r_framecount)

					{

						r_lastvertvalid = false;

						continue;

					}

				}

				else

				{

				// it's cached if the cached edge is valid and is owned

				// by this medge_t

					if ((((unsigned long)edge_p - (unsigned long)r_edges) >

						 r_pedge->cachededgeoffset) &&

						(((edge_t *)((unsigned long)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, view_clipplanes[1].next);

	}

// if no edges made it out, return without posting the surface

	if (!r_emitted)

		return;

	r_polycount++;

	surface_p->data = (void *)fa;

	surface_p->nearzi = r_nearzi;

	surface_p->flags = fa->flags;

	surface_p->insubmodel = insubmodel;

	surface_p->spanstate = 0;

	surface_p->entity = 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 = 1.0 / (pplane->dist - DotProduct (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;

//JDC	VectorCopy (r_worldmodelorg, surface_p->modelorg);

	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;

// 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)

		{

			view_clipplanes[i].next = pclip;

			pclip = &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, view_clipplanes[1].next);

	}

// if no edges made it out, return without posting the surface

	if (!r_emitted)

		return;

	r_polycount++;

	surface_p->data = (void *)psurf;

	surface_p->nearzi = r_nearzi;

	surface_p->flags = psurf->flags;

	surface_p->insubmodel = true;

	surface_p->spanstate = 0;

	surface_p->entity = 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 = 1.0 / (pplane->dist - DotProduct (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;

//JDC	VectorCopy (r_worldmodelorg, surface_p->modelorg);

	surface_p++;

}

/*

================

R_RenderPoly

================

*/

void R_RenderPoly (msurface_t *fa, int clipflags)

{

	int			i, lindex, lnumverts, s_axis, t_axis;

	float		dist, lastdist, lzi, scale, u, v, frac;

	unsigned	mask;

	vec3_t		local, transformed;

	clipplane_t	*pclip;

	medge_t		*pedges;

	mplane_t	*pplane;

	mvertex_t	verts[2][100];	//FIXME: do real number

	polyvert_t	pverts[100];	//FIXME: do real number, safely

	int			vertpage, newverts, newpage, lastvert;

	qboolean	visible;

// FIXME: clean this up and make it faster

// FIXME: guard against running out of vertices

	s_axis = t_axis = 0;	// keep compiler happy

// set up clip planes

	pclip = NULL;

	for (i=3, mask = 0x08 ; i>=0 ; i--, mask >>= 1)

	{

		if (clipflags & mask)

		{

			view_clipplanes[i].next = pclip;

			pclip = &view_clipplanes[i];

		}

	}

// reconstruct the polygon

// FIXME: these should be precalculated and loaded off disk

	pedges = currententity->model->edges;

	lnumverts = fa->numedges;

	vertpage = 0;

	for (i=0 ; i

	{

		lindex = currententity->model->surfedges[fa->firstedge + i];

		if (lindex > 0)

		{

			r_pedge = &pedges[lindex];

			verts[0][i] = r_pcurrentvertbase[r_pedge->v[0]];

		}

		else

		{

			r_pedge = &pedges[-lindex];

			verts[0][i] = r_pcurrentvertbase[r_pedge->v[1]];

		}

	}

// clip the polygon, done if not visible

	while (pclip)

	{

		lastvert = lnumverts - 1;

		lastdist = DotProduct (verts[vertpage][lastvert].position,

							   pclip->normal) - pclip->dist;

		visible = false;

		newverts = 0;

		newpage = vertpage ^ 1;

		for (i=0 ; i

		{

			dist = DotProduct (verts[vertpage][i].position, pclip->normal) -

					pclip->dist;

			if ((lastdist > 0) != (dist > 0))

			{

				frac = dist / (dist - lastdist);

				verts[newpage][newverts].position[0] =

						verts[vertpage][i].position[0] +

						((verts[vertpage][lastvert].position[0] -

						  verts[vertpage][i].position[0]) * frac);

				verts[newpage][newverts].position[1] =

						verts[vertpage][i].position[1] +

						((verts[vertpage][lastvert].position[1] -

						  verts[vertpage][i].position[1]) * frac);

				verts[newpage][newverts].position[2] =

						verts[vertpage][i].position[2] +

						((verts[vertpage][lastvert].position[2] -

						  verts[vertpage][i].position[2]) * frac);

				newverts++;

			}

			if (dist >= 0)

			{

				verts[newpage][newverts] = verts[vertpage][i];

				newverts++;

				visible = true;

			}

			lastvert = i;

			lastdist = dist;

		}

		if (!visible || (newverts < 3))

			return;

		lnumverts = newverts;

		vertpage ^= 1;

		pclip = pclip->next;

	}

// transform and project, remembering the z values at the vertices and

// r_nearzi, and extract the s and t coordinates at the vertices

	pplane = fa->plane;

	switch (pplane->type)

	{

	case PLANE_X:

	case PLANE_ANYX:

		s_axis = 1;

		t_axis = 2;

		break;

	case PLANE_Y:

	case PLANE_ANYY:

		s_axis = 0;

		t_axis = 2;

		break;

	case PLANE_Z:

	case PLANE_ANYZ:

		s_axis = 0;

		t_axis = 1;

		break;

	}

	r_nearzi = 0;

	for (i=0 ; i

	{

	// transform and project

		VectorSubtract (verts[vertpage][i].position, modelorg, local);

		TransformVector (local, transformed);

		if (transformed[2] < NEAR_CLIP)

			transformed[2] = NEAR_CLIP;

		lzi = 1.0 / transformed[2];

		if (lzi > r_nearzi)	// for mipmap finding

			r_nearzi = lzi;

	// FIXME: build x/yscale into transform?

		scale = xscale * lzi;

		u = (xcenter + scale*transformed[0]);

		if (u < r_refdef.fvrectx_adj)

			u = r_refdef.fvrectx_adj;

		if (u > r_refdef.fvrectright_adj)

			u = r_refdef.fvrectright_adj;

		scale = yscale * lzi;

		v = (ycenter - scale*transformed[1]);

		if (v < r_refdef.fvrecty_adj)

			v = r_refdef.fvrecty_adj;

		if (v > r_refdef.fvrectbottom_adj)

			v = r_refdef.fvrectbottom_adj;

		pverts[i].u = u;

		pverts[i].v = v;

		pverts[i].zi = lzi;

		pverts[i].s = verts[vertpage][i].position[s_axis];

		pverts[i].t = verts[vertpage][i].position[t_axis];

	}

// build the polygon descriptor, including fa, r_nearzi, and u, v, s, t, and z

// for each vertex

	r_polydesc.numverts = lnumverts;

	r_polydesc.nearzi = r_nearzi;

	r_polydesc.pcurrentface = fa;

	r_polydesc.pverts = pverts;

// draw the polygon

	D_DrawPoly ();

}

/*

================

R_ZDrawSubmodelPolys

================

*/

void R_ZDrawSubmodelPolys (model_t *pmodel)

{

	int			i, numsurfaces;

	msurface_t	*psurf;

	float		dot;

	mplane_t	*pplane;

	psurf = &pmodel->surfaces[pmodel->firstmodelsurface];

	numsurfaces = pmodel->nummodelsurfaces;

	for (i=0 ; i

	{

	// find which side of the node we are on

		pplane = psurf->plane;

		dot = DotProduct (modelorg, pplane->normal) - pplane->dist;

	// draw the polygon

		if (((psurf->flags & SURF_PLANEBACK) && (dot < -BACKFACE_EPSILON)) ||

			(!(psurf->flags & SURF_PLANEBACK) && (dot > BACKFACE_EPSILON)))

		{

		// FIXME: use bounding-box-based frustum clipping info?

			R_RenderPoly (psurf, 15);

		}

	}

}