1/*
2Copyright (C) 1996-1997 Id Software, Inc.
3
4This program is free software; you can redistribute it and/or
5modify it under the terms of the GNU General Public License
6as published by the Free Software Foundation; either version 2
7of the License, or (at your option) any later version.
8
9This program is distributed in the hope that it will be useful,
10but WITHOUT ANY WARRANTY; without even the implied warranty of
11MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12
13See the GNU General Public License for more details.
14
15You should have received a copy of the GNU General Public License
16along with this program; if not, write to the Free Software
17Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
18
19*/
20// r_light.c
21
22#include "quakedef.h"
23#include "r_local.h"
24
25int	r_dlightframecount;
26
27
28/*
29==================
30R_AnimateLight
31==================
32*/
33void R_AnimateLight (void)
34{
35	int			i,j,k;
36
37//
38// light animations
39// 'm' is normal light, 'a' is no light, 'z' is double bright
40	i = (int)(cl.time*10);
41	for (j=0 ; j<MAX_LIGHTSTYLES ; j++)
42	{
43		if (!cl_lightstyle[j].length)
44		{
45			d_lightstylevalue[j] = 256;
46			continue;
47		}
48		k = i % cl_lightstyle[j].length;
49		k = cl_lightstyle[j].map[k] - 'a';
50		k = k*22;
51		d_lightstylevalue[j] = k;
52	}
53}
54
55
56/*
57=============================================================================
58
59DYNAMIC LIGHTS
60
61=============================================================================
62*/
63
64/*
65=============
66R_MarkLights
67=============
68*/
69void R_MarkLights (dlight_t *light, int bit, mnode_t *node)
70{
71	mplane_t	*splitplane;
72	float		dist;
73	msurface_t	*surf;
74	int			i;
75
76	if (node->contents < 0)
77		return;
78
79	splitplane = node->plane;
80	dist = DotProduct (light->origin, splitplane->normal) - splitplane->dist;
81
82	if (dist > light->radius)
83	{
84		R_MarkLights (light, bit, node->children[0]);
85		return;
86	}
87	if (dist < -light->radius)
88	{
89		R_MarkLights (light, bit, node->children[1]);
90		return;
91	}
92
93// mark the polygons
94	surf = cl.worldmodel->surfaces + node->firstsurface;
95	for (i=0 ; i<node->numsurfaces ; i++, surf++)
96	{
97		if (surf->dlightframe != r_dlightframecount)
98		{
99			surf->dlightbits = 0;
100			surf->dlightframe = r_dlightframecount;
101		}
102		surf->dlightbits |= bit;
103	}
104
105	R_MarkLights (light, bit, node->children[0]);
106	R_MarkLights (light, bit, node->children[1]);
107}
108
109
110/*
111=============
112R_PushDlights
113=============
114*/
115void R_PushDlights (void)
116{
117	int		i;
118	dlight_t	*l;
119
120	r_dlightframecount = r_framecount + 1;	// because the count hasn't
121											//  advanced yet for this frame
122	l = cl_dlights;
123
124	for (i=0 ; i<MAX_DLIGHTS ; i++, l++)
125	{
126		if (l->die < cl.time || !l->radius)
127			continue;
128		R_MarkLights ( l, 1<<i, cl.worldmodel->nodes );
129	}
130}
131
132
133/*
134=============================================================================
135
136LIGHT SAMPLING
137
138=============================================================================
139*/
140
141int RecursiveLightPoint (mnode_t *node, vec3_t start, vec3_t end)
142{
143	int			r;
144	float		front, back, frac;
145	int			side;
146	mplane_t	*plane;
147	vec3_t		mid;
148	msurface_t	*surf;
149	int			s, t, ds, dt;
150	int			i;
151	mtexinfo_t	*tex;
152	byte		*lightmap;
153	unsigned	scale;
154	int			maps;
155
156	if (node->contents < 0)
157		return -1;		// didn't hit anything
158
159// calculate mid point
160
161// FIXME: optimize for axial
162	plane = node->plane;
163	front = DotProduct (start, plane->normal) - plane->dist;
164	back = DotProduct (end, plane->normal) - plane->dist;
165	side = front < 0;
166
167	if ( (back < 0) == side)
168		return RecursiveLightPoint (node->children[side], start, end);
169
170	frac = front / (front-back);
171	mid[0] = start[0] + (end[0] - start[0])*frac;
172	mid[1] = start[1] + (end[1] - start[1])*frac;
173	mid[2] = start[2] + (end[2] - start[2])*frac;
174
175// go down front side
176	r = RecursiveLightPoint (node->children[side], start, mid);
177	if (r >= 0)
178		return r;		// hit something
179
180	if ( (back < 0) == side )
181		return -1;		// didn't hit anuthing
182
183// check for impact on this node
184
185	surf = cl.worldmodel->surfaces + node->firstsurface;
186	for (i=0 ; i<node->numsurfaces ; i++, surf++)
187	{
188		if (surf->flags & SURF_DRAWTILED)
189			continue;	// no lightmaps
190
191		tex = surf->texinfo;
192
193		s = DotProduct (mid, tex->vecs[0]) + tex->vecs[0][3];
194		t = DotProduct (mid, tex->vecs[1]) + tex->vecs[1][3];;
195
196		if (s < surf->texturemins[0] ||
197		t < surf->texturemins[1])
198			continue;
199
200		ds = s - surf->texturemins[0];
201		dt = t - surf->texturemins[1];
202
203		if ( ds > surf->extents[0] || dt > surf->extents[1] )
204			continue;
205
206		if (!surf->samples)
207			return 0;
208
209		ds >>= 4;
210		dt >>= 4;
211
212		lightmap = surf->samples;
213		r = 0;
214		if (lightmap)
215		{
216
217			lightmap += dt * ((surf->extents[0]>>4)+1) + ds;
218
219			for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
220					maps++)
221			{
222				scale = d_lightstylevalue[surf->styles[maps]];
223				r += *lightmap * scale;
224				lightmap += ((surf->extents[0]>>4)+1) *
225						((surf->extents[1]>>4)+1);
226			}
227
228			r >>= 8;
229		}
230
231		return r;
232	}
233
234// go down back side
235	return RecursiveLightPoint (node->children[!side], mid, end);
236}
237
238int R_LightPoint (vec3_t p)
239{
240	vec3_t		end;
241	int			r;
242
243	if (!cl.worldmodel->lightdata)
244		return 255;
245
246	end[0] = p[0];
247	end[1] = p[1];
248	end[2] = p[2] - 2048;
249
250	r = RecursiveLightPoint (cl.worldmodel->nodes, p, end);
251
252	if (r == -1)
253		r = 0;
254
255	if (r < r_refdef.ambientlight)
256		r = r_refdef.ambientlight;
257
258	return r;
259}
260
261