/*
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"

int	r_dlightframecount;

mplane_t		*lightplane;

vec3_t			lightspot;
vec3_t			lightcolor;
/*
==================
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<MAX_LIGHTSTYLES ; 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;

	// Tomaz - Lit Support Begin
	float		l, maxdist;
	int			j, s, t;
	vec3_t		impact;
loc0:
	// Tomaz - Lit Support End

	if (node->contents < 0)
		return;

	splitplane = node->plane;
	// Tomaz - Lit Support Begin
	if (splitplane->type < 3)
		dist = light->origin[splitplane->type] - splitplane->dist;
	else
		dist = DotProduct (light->origin, splitplane->normal) - splitplane->dist;
	// Tomaz - Lit Support End
	if (dist > light->radius)
	{
		// Tomaz - Lit Support Begin
		node = node->children[0];
		goto loc0;
		// Tomaz - Lit Support End
	}
	if (dist < -light->radius)
	{
		// Tomaz - Lit Support Begin
		node = node->children[1];
		goto loc0;
		// Tomaz - Lit Support End
	}

	maxdist = light->radius*light->radius; // Tomaz - Lit Support

// mark the polygons
	surf = cl.worldmodel->surfaces + node->firstsurface;
	for (i=0 ; i<node->numsurfaces ; i++, surf++)
	{
		// Tomaz - Lit Support Begin
		for (j=0 ; j<3 ; j++)
			impact[j] = light->origin[j] - surf->plane->normal[j]*dist;

		// clamp center of light to corner and check brightness
		l = DotProduct (impact, surf->texinfo->vecs[0]) + surf->texinfo->vecs[0][3] - surf->texturemins[0];
		s = l+0.5;
		if (s < 0) 
			s = 0;
		else if (s > surf->extents[0]) 
			s = surf->extents[0];
		s = l - s;
		l = DotProduct (impact, surf->texinfo->vecs[1]) + surf->texinfo->vecs[1][3] - surf->texturemins[1];
		t = l+0.5;
		if (t < 0) 
			t = 0;
		else if (t > surf->extents[1]) 
			t = surf->extents[1];
		t = l - t;
		// compare to minimum light
		if ((s*s+t*t+dist*dist) < maxdist)
		{
			if (surf->dlightframe != r_dlightframecount) // not dynamic until now
			{
				surf->dlightbits = bit;
				surf->dlightframe = r_dlightframecount;
			}
			else // already dynamic
				surf->dlightbits |= bit;
		}
		// Tomaz - Lit Support End
	}

	// Tomaz - Lit Support Begin
	if (node->children[0]->contents >= 0)
		R_MarkLights (light, bit, node->children[0]);
	if (node->children[1]->contents >= 0)
		R_MarkLights (light, bit, node->children[1]);
	// Tomaz - Lit Support End
}


/*
=============
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<MAX_DLIGHTS ; i++, l++)
	{
		if (l->die < cl.time || !l->radius)
			continue;
		R_MarkLights ( l, 1<<i, cl.worldmodel->nodes );
	}
}


/*
=============================================================================

LIGHT SAMPLING

=============================================================================
*/

// Tomaz - Lit Support Begin
int RecursiveLightPoint (vec3_t color, mnode_t *node, vec3_t start, vec3_t end)
{
	float		front, back, frac;
	vec3_t		mid;

loc0:
	if (node->contents < 0)
		return false;		// didn't hit anything
	
// calculate mid point
	if (node->plane->type < 3)
	{
		front = start[node->plane->type] - node->plane->dist;
		back = end[node->plane->type] - node->plane->dist;
	}
	else
	{
		front = DotProduct(start, node->plane->normal) - node->plane->dist;
		back = DotProduct(end, node->plane->normal) - node->plane->dist;
	}

	if ((back < 0) == (front < 0))
	{
		node = node->children[front < 0];
		goto loc0;
	}
	
	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
	if (RecursiveLightPoint (color, node->children[front < 0], start, mid))
		return true;	// hit something
	else
	{
		int i, ds, dt;
		msurface_t *surf;
	// check for impact on this node
		VectorCopy (mid, lightspot);
		lightplane = node->plane;

		surf = cl.worldmodel->surfaces + node->firstsurface;
		for (i = 0;i < node->numsurfaces;i++, surf++)
		{
			if (surf->flags & SURF_DRAWTILED)
				continue;	// no lightmaps

			ds = (int) ((float) DotProduct (mid, surf->texinfo->vecs[0]) + surf->texinfo->vecs[0][3]);
			dt = (int) ((float) DotProduct (mid, surf->texinfo->vecs[1]) + surf->texinfo->vecs[1][3]);

			if (ds < surf->texturemins[0] || dt < surf->texturemins[1])
				continue;
			
			ds -= surf->texturemins[0];
			dt -= surf->texturemins[1];
			
			if (ds > surf->extents[0] || dt > surf->extents[1])
				continue;

			if (surf->samples)
			{
				byte *lightmap;
				int maps, line3, dsfrac = ds & 15, dtfrac = dt & 15, r00 = 0, g00 = 0, b00 = 0, r01 = 0, g01 = 0, b01 = 0, r10 = 0, g10 = 0, b10 = 0, r11 = 0, g11 = 0, b11 = 0;
				float scale;
				line3 = ((surf->extents[0]>>4)+1)*3;

				lightmap = surf->samples + ((dt>>4) * ((surf->extents[0]>>4)+1) + (ds>>4))*3;

				for (maps = 0;maps < MAXLIGHTMAPS && surf->styles[maps] != 255;maps++)
				{
					scale = (float) d_lightstylevalue[surf->styles[maps]] * 1.0 / 256.0;	// Tomaz - Speed
					// NOTE: r=red, g=green, b=blue
					// numbers are tex-coords
					r00 += (float) lightmap[      0] * scale; // red 00
					g00 += (float) lightmap[      1] * scale; // green 00
					b00 += (float) lightmap[	  2] * scale; // blue 00
					r01 += (float) lightmap[      3] * scale; // red 01
					g01 += (float) lightmap[      4] * scale; // green 01
					b01 += (float) lightmap[      5] * scale; // blue 01	
					r10 += (float) lightmap[line3+0] * scale; // red 10
					g10 += (float) lightmap[line3+1] * scale; // green 10
					b10 += (float) lightmap[line3+2] * scale; // blue 10
					r11 += (float) lightmap[line3+3] * scale; // red 11
					g11 += (float) lightmap[line3+4] * scale; // green 11
					b11 += (float) lightmap[line3+5] * scale; // blue 11
					lightmap += ((surf->extents[0]>>4)+1) * ((surf->extents[1]>>4)+1)*3;
				}

				color[0] += (float) ((int) ((((((((r11-r10) * dsfrac) >> 4) + r10)-((((r01-r00) * dsfrac) >> 4) + r00)) * dtfrac) >> 4) + ((((r01-r00) * dsfrac) >> 4) + r00)));
				color[1] += (float) ((int) ((((((((g11-g10) * dsfrac) >> 4) + g10)-((((g01-g00) * dsfrac) >> 4) + g00)) * dtfrac) >> 4) + ((((g01-g00) * dsfrac) >> 4) + g00)));
				color[2] += (float) ((int) ((((((((b11-b10) * dsfrac) >> 4) + b10)-((((b01-b00) * dsfrac) >> 4) + b00)) * dtfrac) >> 4) + ((((b01-b00) * dsfrac) >> 4) + b00)));
			}
			return true; // success
		}

	// go down back side
		return RecursiveLightPoint (color, node->children[front >= 0], mid, end);
	}
}

int R_LightPoint (vec3_t p)
{
	vec3_t		end;
	
	if (!cl.worldmodel->lightdata)
	{
		lightcolor[0] = lightcolor[1] = lightcolor[2] = 255;
		return 255;
	}
	
	end[0] = p[0];
	end[1] = p[1];
	end[2] = p[2] - 2048;

	lightcolor[0] = lightcolor[1] = lightcolor[2] = 0;
	RecursiveLightPoint (lightcolor, cl.worldmodel->nodes, p, end);
	return ((lightcolor[0] + lightcolor[1] + lightcolor[2]) * (0.3333333333));
}
// Tomaz - Lit Support End