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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_light.c

#include "quakedef.h"

#include "r_local.h"

int	r_dlightframecount;

/*

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

R_AnimateLight

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

*/

void R_AnimateLight (void)

{

	int			i,j,k;

//

// light animations

// 'm' is normal light, 'a' is no light, 'z' is double bright

	i = (int)(cl.time*10);

	for (j=0 ; j

	{

		if (!cl_lightstyle[j].length)

		{

			d_lightstylevalue[j] = 256;

			continue;

		}

		k = i % cl_lightstyle[j].length;

		k = cl_lightstyle[j].map[k] - 'a';

		k = k*22;

		d_lightstylevalue[j] = k;

	}

}

/*

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

DYNAMIC LIGHTS

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

*/

/*

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

R_MarkLights

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

*/

void R_MarkLights (dlight_t *light, int bit, mnode_t *node)

{

	mplane_t	*splitplane;

	float		dist;

	msurface_t	*surf;

	int			i;

	if (node->contents < 0)

		return;

	splitplane = node->plane;

	dist = DotProduct (light->origin, splitplane->normal) - splitplane->dist;

	if (dist > light->radius)

	{

		R_MarkLights (light, bit, node->children[0]);

		return;

	}

	if (dist < -light->radius)

	{

		R_MarkLights (light, bit, node->children[1]);

		return;

	}

// mark the polygons

	surf = cl.worldmodel->surfaces + node->firstsurface;

	for (i=0 ; inumsurfaces ; i++, surf++)

	{

		if (surf->dlightframe != r_dlightframecount)

		{

			surf->dlightbits = 0;

			surf->dlightframe = r_dlightframecount;

		}

		surf->dlightbits |= bit;

	}

	R_MarkLights (light, bit, node->children[0]);

	R_MarkLights (light, bit, node->children[1]);

}

/*

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

R_PushDlights

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

*/

void R_PushDlights (void)

{

	int		i;

	dlight_t	*l;

	r_dlightframecount = r_framecount + 1;	// because the count hasn't

											//  advanced yet for this frame

	l = cl_dlights;

	for (i=0 ; i

	{

		if (l->die < cl.time || !l->radius)

			continue;

		R_MarkLights ( l, 1<nodes );

	}

}

/*

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

LIGHT SAMPLING

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

*/

int RecursiveLightPoint (mnode_t *node, vec3_t start, vec3_t end)

{

	int			r;

	float		front, back, frac;

	int			side;

	mplane_t	*plane;

	vec3_t		mid;

	msurface_t	*surf;

	int			s, t, ds, dt;

	int			i;

	mtexinfo_t	*tex;

	byte		*lightmap;

	unsigned	scale;

	int			maps;

	if (node->contents < 0)

		return -1;		// didn't hit anything

// calculate mid point

// FIXME: optimize for axial

	plane = node->plane;

	front = DotProduct (start, plane->normal) - plane->dist;

	back = DotProduct (end, plane->normal) - plane->dist;

	side = front < 0;

	if ( (back < 0) == side)

		return RecursiveLightPoint (node->children[side], start, end);

	frac = front / (front-back);

	mid[0] = start[0] + (end[0] - start[0])*frac;

	mid[1] = start[1] + (end[1] - start[1])*frac;

	mid[2] = start[2] + (end[2] - start[2])*frac;

// go down front side

	r = RecursiveLightPoint (node->children[side], start, mid);

	if (r >= 0)

		return r;		// hit something

	if ( (back < 0) == side )

		return -1;		// didn't hit anuthing

// check for impact on this node

	surf = cl.worldmodel->surfaces + node->firstsurface;

	for (i=0 ; inumsurfaces ; i++, surf++)

	{

		if (surf->flags & SURF_DRAWTILED)

			continue;	// no lightmaps

		tex = surf->texinfo;

		s = DotProduct (mid, tex->vecs[0]) + tex->vecs[0][3];

		t = DotProduct (mid, tex->vecs[1]) + tex->vecs[1][3];;

		if (s < surf->texturemins[0] ||

		t < surf->texturemins[1])

			continue;

		ds = s - surf->texturemins[0];

		dt = t - surf->texturemins[1];

		if ( ds > surf->extents[0] || dt > surf->extents[1] )

			continue;

		if (!surf->samples)

			return 0;

		ds >>= 4;

		dt >>= 4;

		lightmap = surf->samples;

		r = 0;

		if (lightmap)

		{

			lightmap += dt * ((surf->extents[0]>>4)+1) + ds;

			for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;

					maps++)

			{

				scale = d_lightstylevalue[surf->styles[maps]];

				r += *lightmap * scale;

				lightmap += ((surf->extents[0]>>4)+1) *

						((surf->extents[1]>>4)+1);

			}

			r >>= 8;

		}

		return r;

	}

// go down back side

	return RecursiveLightPoint (node->children[!side], mid, end);

}

int R_LightPoint (vec3_t p)

{

	vec3_t		end;

	int			r;

	if (!cl.worldmodel->lightdata)

		return 255;

	end[0] = p[0];

	end[1] = p[1];

	end[2] = p[2] - 2048;

	r = RecursiveLightPoint (cl.worldmodel->nodes, p, end);

	if (r == -1)

		r = 0;

	if (r < r_refdef.ambientlight)

		r = r_refdef.ambientlight;

	return r;

}