added a note to optimize the MAX_DLIGHTS loop somehow
[xonotic/darkplaces.git] / r_light.c
1 /*
2 Copyright (C) 1996-1997 Id Software, Inc.
3
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12
13 See the GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
18
19 */
20 // r_light.c
21
22 #include "quakedef.h"
23 #include "cl_collision.h"
24 #include "r_shadow.h"
25
26 dlight_t r_dlight[MAX_DLIGHTS];
27 int r_numdlights = 0;
28
29 cvar_t r_modellights = {CVAR_SAVE, "r_modellights", "4"};
30 cvar_t r_vismarklights = {0, "r_vismarklights", "1"};
31 cvar_t r_coronas = {CVAR_SAVE, "r_coronas", "1"};
32 cvar_t gl_flashblend = {CVAR_SAVE, "gl_flashblend", "1"};
33
34 static rtexture_t *lightcorona;
35 static rtexturepool_t *lighttexturepool;
36
37 void r_light_start(void)
38 {
39         float dx, dy;
40         int x, y, a;
41         qbyte pixels[32][32][4];
42         lighttexturepool = R_AllocTexturePool();
43         for (y = 0;y < 32;y++)
44         {
45                 dy = (y - 15.5f) * (1.0f / 16.0f);
46                 for (x = 0;x < 32;x++)
47                 {
48                         dx = (x - 15.5f) * (1.0f / 16.0f);
49                         a = ((1.0f / (dx * dx + dy * dy + 0.2f)) - (1.0f / (1.0f + 0.2))) * 32.0f / (1.0f / (1.0f + 0.2));
50                         a = bound(0, a, 255);
51                         pixels[y][x][0] = a;
52                         pixels[y][x][1] = a;
53                         pixels[y][x][2] = a;
54                         pixels[y][x][3] = 255;
55                 }
56         }
57         lightcorona = R_LoadTexture2D(lighttexturepool, "lightcorona", 32, 32, &pixels[0][0][0], TEXTYPE_RGBA, TEXF_PRECACHE, NULL);
58 }
59
60 void r_light_shutdown(void)
61 {
62         lighttexturepool = NULL;
63         lightcorona = NULL;
64 }
65
66 void r_light_newmap(void)
67 {
68         int i;
69         for (i = 0;i < 256;i++)
70                 d_lightstylevalue[i] = 264;             // normal light value
71 }
72
73 void R_Light_Init(void)
74 {
75         Cvar_RegisterVariable(&r_modellights);
76         Cvar_RegisterVariable(&r_vismarklights);
77         Cvar_RegisterVariable(&r_coronas);
78         Cvar_RegisterVariable(&gl_flashblend);
79         R_RegisterModule("R_Light", r_light_start, r_light_shutdown, r_light_newmap);
80 }
81
82 /*
83 ==================
84 R_UpdateLights
85 ==================
86 */
87 void R_UpdateLights(void)
88 {
89         int i, j, k;
90
91 // light animations
92 // 'm' is normal light, 'a' is no light, 'z' is double bright
93         i = (int)(cl.time * 10);
94         for (j = 0;j < MAX_LIGHTSTYLES;j++)
95         {
96                 if (!cl_lightstyle || !cl_lightstyle[j].length)
97                 {
98                         d_lightstylevalue[j] = 256;
99                         continue;
100                 }
101                 k = i % cl_lightstyle[j].length;
102                 k = cl_lightstyle[j].map[k] - 'a';
103                 k = k*22;
104                 d_lightstylevalue[j] = k;
105         }
106
107         r_numdlights = 0;
108         c_dlights = 0;
109
110         if (!r_dynamic.integer || !cl_dlights)
111                 return;
112
113         // TODO: optimize to not scan whole cl_dlights array if possible
114         for (i = 0;i < MAX_DLIGHTS;i++)
115         {
116                 if (cl_dlights[i].radius > 0)
117                 {
118                         R_RTLight_UpdateFromDLight(&cl_dlights[i].rtlight, &cl_dlights[i], false);
119                         // FIXME: use pointer instead of copy
120                         r_dlight[r_numdlights++] = cl_dlights[i];
121                         c_dlights++; // count every dlight in use
122                 }
123         }
124 }
125
126 void R_DrawCoronas(void)
127 {
128         int i, lnum;
129         float cscale, scale, viewdist, dist;
130         dlight_t *light;
131         if (!r_coronas.integer)
132                 return;
133         R_Mesh_Matrix(&r_identitymatrix);
134         viewdist = DotProduct(r_vieworigin, r_viewforward);
135         if (r_shadow_realtime_world.integer)
136         {
137                 for (lnum = 0, light = r_shadow_worldlightchain;light;light = light->next, lnum++)
138                 {
139                         if (light->rtlight.corona * r_coronas.value > 0 && (r_shadow_debuglight.integer < 0 || r_shadow_debuglight.integer == lnum) && (dist = (DotProduct(light->rtlight.shadoworigin, r_viewforward) - viewdist)) >= 24.0f && CL_TraceLine(light->rtlight.shadoworigin, r_vieworigin, NULL, NULL, true, NULL, SUPERCONTENTS_SOLID) == 1)
140                         {
141                                 cscale = light->rtlight.corona * r_coronas.value * 0.25f;
142                                 scale = light->rtlight.radius * 0.25f;
143                                 R_DrawSprite(GL_ONE, GL_ONE, lightcorona, true, light->rtlight.shadoworigin, r_viewright, r_viewup, scale, -scale, -scale, scale, light->rtlight.color[0] * cscale, light->rtlight.color[1] * cscale, light->rtlight.color[2] * cscale, 1);
144                         }
145                 }
146         }
147         for (i = 0, light = r_dlight;i < r_numdlights;i++, light++)
148         {
149                 if (light->corona * r_coronas.value > 0 && (dist = (DotProduct(light->origin, r_viewforward) - viewdist)) >= 24.0f && CL_TraceLine(light->origin, r_vieworigin, NULL, NULL, true, NULL, SUPERCONTENTS_SOLID) == 1)
150                 {
151                         cscale = light->corona * r_coronas.value * 0.25f;
152                         scale = light->radius * 0.25f;
153                         if (gl_flashblend.integer)
154                         {
155                                 cscale *= 4.0f;
156                                 scale *= 2.0f;
157                         }
158                         R_DrawSprite(GL_ONE, GL_ONE, lightcorona, true, light->origin, r_viewright, r_viewup, scale, -scale, -scale, scale, light->color[0] * cscale, light->color[1] * cscale, light->color[2] * cscale, 1);
159                 }
160         }
161 }
162
163 /*
164 =============================================================================
165
166 DYNAMIC LIGHTS
167
168 =============================================================================
169 */
170
171 static int lightpvsbytes;
172 static qbyte lightpvs[(MAX_MAP_LEAFS+7)>>3];
173
174 /*
175 =============
176 R_MarkLights
177 =============
178 */
179 static void R_RecursiveMarkLights(entity_render_t *ent, vec3_t lightorigin, dlight_t *light, int bit, int bitindex, mnode_t *node, qbyte *pvs, int pvsbits)
180 {
181         int i;
182         mleaf_t *leaf;
183         float dist;
184
185         // for comparisons to minimum acceptable light
186         while(node->contents >= 0)
187         {
188                 dist = PlaneDiff(lightorigin, node->plane);
189                 if (dist > light->rtlight.lightmap_cullradius)
190                         node = node->children[0];
191                 else
192                 {
193                         if (dist >= -light->rtlight.lightmap_cullradius)
194                                 R_RecursiveMarkLights(ent, lightorigin, light, bit, bitindex, node->children[0], pvs, pvsbits);
195                         node = node->children[1];
196                 }
197         }
198
199         // check if leaf is visible according to pvs
200         leaf = (mleaf_t *)node;
201         i = leaf->clusterindex;
202         if (leaf->nummarksurfaces && (i >= pvsbits || CHECKPVSBIT(pvs, i)))
203         {
204                 int *surfacepvsframes, d, impacts, impactt;
205                 float sdist, maxdist, dist2, impact[3];
206                 msurface_t *surf;
207                 // mark the polygons
208                 maxdist = light->rtlight.lightmap_cullradius2;
209                 surfacepvsframes = ent->model->brushq1.surfacepvsframes;
210                 for (i = 0;i < leaf->nummarksurfaces;i++)
211                 {
212                         if (surfacepvsframes[leaf->firstmarksurface[i]] != ent->model->brushq1.pvsframecount)
213                                 continue;
214                         surf = ent->model->brushq1.surfaces + leaf->firstmarksurface[i];
215                         dist = sdist = PlaneDiff(lightorigin, surf->plane);
216                         if (surf->flags & SURF_PLANEBACK)
217                                 dist = -dist;
218
219                         if (dist < -0.25f && !(surf->flags & SURF_LIGHTBOTHSIDES))
220                                 continue;
221
222                         dist2 = dist * dist;
223                         if (dist2 >= maxdist)
224                                 continue;
225
226                         VectorCopy(lightorigin, impact);
227                         if (surf->plane->type >= 3)
228                                 VectorMA(impact, -sdist, surf->plane->normal, impact);
229                         else
230                                 impact[surf->plane->type] -= sdist;
231
232                         impacts = DotProduct (impact, surf->texinfo->vecs[0]) + surf->texinfo->vecs[0][3] - surf->texturemins[0];
233
234                         d = bound(0, impacts, surf->extents[0] + 16) - impacts;
235                         dist2 += d * d;
236                         if (dist2 > maxdist)
237                                 continue;
238
239                         impactt = DotProduct (impact, surf->texinfo->vecs[1]) + surf->texinfo->vecs[1][3] - surf->texturemins[1];
240
241                         d = bound(0, impactt, surf->extents[1] + 16) - impactt;
242                         dist2 += d * d;
243                         if (dist2 > maxdist)
244                                 continue;
245
246                         if (surf->dlightframe != r_framecount) // not dynamic until now
247                         {
248                                 surf->dlightbits[0] = surf->dlightbits[1] = surf->dlightbits[2] = surf->dlightbits[3] = surf->dlightbits[4] = surf->dlightbits[5] = surf->dlightbits[6] = surf->dlightbits[7] = 0;
249                                 surf->dlightframe = r_framecount;
250                                 surf->cached_dlight = true;
251                         }
252                         surf->dlightbits[bitindex] |= bit;
253                 }
254         }
255 }
256
257 void R_MarkLights(entity_render_t *ent)
258 {
259         int i, bit, bitindex;
260         dlight_t *light;
261         vec3_t lightorigin;
262         if (!gl_flashblend.integer && r_dynamic.integer && ent->model && ent->model->brushq1.num_leafs)
263         {
264                 for (i = 0, light = r_dlight;i < r_numdlights;i++, light++)
265                 {
266                         bit = 1 << (i & 31);
267                         bitindex = i >> 5;
268                         Matrix4x4_Transform(&ent->inversematrix, light->origin, lightorigin);
269                         lightpvsbytes = 0;
270                         if (r_vismarklights.integer && ent->model->brush.FatPVS)
271                                 lightpvsbytes = ent->model->brush.FatPVS(ent->model, lightorigin, 0, lightpvs, sizeof(lightpvs));
272                         R_RecursiveMarkLights(ent, lightorigin, light, bit, bitindex, ent->model->brushq1.nodes + ent->model->brushq1.hulls[0].firstclipnode, lightpvs, min(lightpvsbytes * 8, ent->model->brush.num_pvsclusters));
273                 }
274         }
275 }
276
277 /*
278 =============================================================================
279
280 LIGHT SAMPLING
281
282 =============================================================================
283 */
284
285 void R_CompleteLightPoint(vec3_t ambientcolor, vec3_t diffusecolor, vec3_t diffusenormal, const vec3_t p, int dynamic, const mleaf_t *leaf)
286 {
287         VectorClear(diffusecolor);
288         VectorClear(diffusenormal);
289
290         if (!r_fullbright.integer && cl.worldmodel && cl.worldmodel->brush.LightPoint)
291         {
292                 ambientcolor[0] = ambientcolor[1] = ambientcolor[2] = r_ambient.value * (2.0f / 128.0f);
293                 cl.worldmodel->brush.LightPoint(cl.worldmodel, p, ambientcolor, diffusecolor, diffusenormal);
294         }
295         else
296                 VectorSet(ambientcolor, 1, 1, 1);
297
298         // FIXME: this .lights related stuff needs to be ported into the Mod_Q1BSP code
299         if (cl.worldmodel->brushq1.numlights)
300         {
301                 int i;
302                 vec3_t v;
303                 float f;
304                 mlight_t *sl;
305                 for (i = 0;i < cl.worldmodel->brushq1.numlights;i++)
306                 {
307                         sl = cl.worldmodel->brushq1.lights + i;
308                         if (d_lightstylevalue[sl->style] > 0)
309                         {
310                                 VectorSubtract (p, sl->origin, v);
311                                 f = ((1.0f / (DotProduct(v, v) * sl->falloff + sl->distbias)) - sl->subtract);
312                                 if (f > 0 && CL_TraceLine(p, sl->origin, NULL, NULL, false, NULL, SUPERCONTENTS_SOLID) == 1)
313                                 {
314                                         f *= d_lightstylevalue[sl->style] * (1.0f / 65536.0f);
315                                         VectorMA(ambientcolor, f, sl->light, ambientcolor);
316                                 }
317                         }
318                 }
319         }
320
321         if (dynamic)
322         {
323                 int i;
324                 float f, v[3];
325                 dlight_t *light;
326                 // FIXME: this really should handle dlights as diffusecolor/diffusenormal somehow
327                 for (i = 0;i < r_numdlights;i++)
328                 {
329                         light = r_dlight + i;
330                         VectorSubtract(p, light->origin, v);
331                         f = DotProduct(v, v);
332                         if (f < light->rtlight.lightmap_cullradius2 && CL_TraceLine(p, light->origin, NULL, NULL, false, NULL, SUPERCONTENTS_SOLID) == 1)
333                         {
334                                 f = (1.0f / (f + LIGHTOFFSET)) - light->rtlight.lightmap_subtract;
335                                 VectorMA(ambientcolor, f, light->rtlight.lightmap_light, ambientcolor);
336                         }
337                 }
338         }
339 }
340
341 typedef struct
342 {
343         vec3_t origin;
344         //vec_t cullradius2;
345         vec3_t light;
346         // how much this light would contribute to ambient if replaced
347         vec3_t ambientlight;
348         vec_t subtract;
349         vec_t falloff;
350         vec_t offset;
351         // used for choosing only the brightest lights
352         vec_t intensity;
353 }
354 nearlight_t;
355
356 static int nearlights;
357 static nearlight_t nearlight[MAX_DLIGHTS];
358
359 int R_LightModel(float *ambient4f, float *diffusecolor, float *diffusenormal, const entity_render_t *ent, float colorr, float colorg, float colorb, float colora, int worldcoords)
360 {
361         int i, j, maxnearlights;
362         float v[3], f, mscale, stylescale, intensity, ambientcolor[3], tempdiffusenormal[3];
363         nearlight_t *nl;
364         mlight_t *sl;
365         dlight_t *light;
366
367         nearlights = 0;
368         maxnearlights = r_modellights.integer;
369         ambient4f[0] = ambient4f[1] = ambient4f[2] = r_ambient.value * (2.0f / 128.0f);
370         VectorClear(diffusecolor);
371         VectorClear(diffusenormal);
372         if (r_fullbright.integer || (ent->effects & EF_FULLBRIGHT))
373         {
374                 // highly rare
375                 VectorSet(ambient4f, 1, 1, 1);
376                 maxnearlights = 0;
377         }
378         else if (r_shadow_realtime_world.integer && r_shadow_realtime_world_lightmaps.value <= 0)
379                 maxnearlights = 0;
380         else
381         {
382                 if (cl.worldmodel && cl.worldmodel->brush.LightPoint)
383                 {
384                         cl.worldmodel->brush.LightPoint(cl.worldmodel, ent->origin, ambient4f, diffusecolor, tempdiffusenormal);
385                         Matrix4x4_Transform3x3(&ent->inversematrix, tempdiffusenormal, diffusenormal);
386                         VectorNormalize(diffusenormal);
387                 }
388                 else
389                         VectorSet(ambient4f, 1, 1, 1);
390         }
391
392         // scale of the model's coordinate space, to alter light attenuation to match
393         // make the mscale squared so it can scale the squared distance results
394         mscale = ent->scale * ent->scale;
395         // FIXME: no support for .lights on non-Q1BSP?
396         nl = &nearlight[0];
397         for (i = 0;i < ent->numentlights;i++)
398         {
399                 sl = cl.worldmodel->brushq1.lights + ent->entlights[i];
400                 stylescale = d_lightstylevalue[sl->style] * (1.0f / 65536.0f);
401                 VectorSubtract (ent->origin, sl->origin, v);
402                 f = ((1.0f / (DotProduct(v, v) * sl->falloff + sl->distbias)) - sl->subtract) * stylescale;
403                 VectorScale(sl->light, f, ambientcolor);
404                 intensity = DotProduct(ambientcolor, ambientcolor);
405                 if (f < 0)
406                         intensity *= -1.0f;
407                 if (nearlights < maxnearlights)
408                         j = nearlights++;
409                 else
410                 {
411                         for (j = 0;j < maxnearlights;j++)
412                         {
413                                 if (nearlight[j].intensity < intensity)
414                                 {
415                                         if (nearlight[j].intensity > 0)
416                                                 VectorAdd(ambient4f, nearlight[j].ambientlight, ambient4f);
417                                         break;
418                                 }
419                         }
420                 }
421                 if (j >= maxnearlights)
422                 {
423                         // this light is less significant than all others,
424                         // add it to ambient
425                         if (intensity > 0)
426                                 VectorAdd(ambient4f, ambientcolor, ambient4f);
427                 }
428                 else
429                 {
430                         nl = nearlight + j;
431                         nl->intensity = intensity;
432                         // transform the light into the model's coordinate system
433                         if (worldcoords)
434                                 VectorCopy(sl->origin, nl->origin);
435                         else
436                                 Matrix4x4_Transform(&ent->inversematrix, sl->origin, nl->origin);
437                         // integrate mscale into falloff, for maximum speed
438                         nl->falloff = sl->falloff * mscale;
439                         VectorCopy(ambientcolor, nl->ambientlight);
440                         nl->light[0] = sl->light[0] * stylescale * colorr * 4.0f;
441                         nl->light[1] = sl->light[1] * stylescale * colorg * 4.0f;
442                         nl->light[2] = sl->light[2] * stylescale * colorb * 4.0f;
443                         nl->subtract = sl->subtract;
444                         nl->offset = sl->distbias;
445                 }
446         }
447         if (!r_shadow_realtime_dlight.integer)
448         {
449                 for (i = 0;i < r_numdlights;i++)
450                 {
451                         light = r_dlight + i;
452                         VectorCopy(light->origin, v);
453                         if (v[0] < ent->mins[0]) v[0] = ent->mins[0];if (v[0] > ent->maxs[0]) v[0] = ent->maxs[0];
454                         if (v[1] < ent->mins[1]) v[1] = ent->mins[1];if (v[1] > ent->maxs[1]) v[1] = ent->maxs[1];
455                         if (v[2] < ent->mins[2]) v[2] = ent->mins[2];if (v[2] > ent->maxs[2]) v[2] = ent->maxs[2];
456                         VectorSubtract (v, light->origin, v);
457                         if (DotProduct(v, v) < light->rtlight.lightmap_cullradius2)
458                         {
459                                 if (CL_TraceLine(ent->origin, light->origin, NULL, NULL, false, NULL, SUPERCONTENTS_SOLID) != 1)
460                                         continue;
461                                 VectorSubtract (ent->origin, light->origin, v);
462                                 f = ((1.0f / (DotProduct(v, v) + LIGHTOFFSET)) - light->rtlight.lightmap_subtract);
463                                 VectorScale(light->rtlight.lightmap_light, f, ambientcolor);
464                                 intensity = DotProduct(ambientcolor, ambientcolor);
465                                 if (f < 0)
466                                         intensity *= -1.0f;
467                                 if (nearlights < maxnearlights)
468                                         j = nearlights++;
469                                 else
470                                 {
471                                         for (j = 0;j < maxnearlights;j++)
472                                         {
473                                                 if (nearlight[j].intensity < intensity)
474                                                 {
475                                                         if (nearlight[j].intensity > 0)
476                                                                 VectorAdd(ambient4f, nearlight[j].ambientlight, ambient4f);
477                                                         break;
478                                                 }
479                                         }
480                                 }
481                                 if (j >= maxnearlights)
482                                 {
483                                         // this light is less significant than all others,
484                                         // add it to ambient
485                                         if (intensity > 0)
486                                                 VectorAdd(ambient4f, ambientcolor, ambient4f);
487                                 }
488                                 else
489                                 {
490                                         nl = nearlight + j;
491                                         nl->intensity = intensity;
492                                         // transform the light into the model's coordinate system
493                                         if (worldcoords)
494                                                 VectorCopy(light->origin, nl->origin);
495                                         else
496                                         {
497                                                 Matrix4x4_Transform(&ent->inversematrix, light->origin, nl->origin);
498                                                 /*
499                                                 Con_Printf("%i %s : %f %f %f : %f %f %f\n%f %f %f %f\n%f %f %f %f\n%f %f %f %f\n%f %f %f %f\n"
500                                                 , rd - r_dlight, ent->model->name
501                                                 , light->origin[0], light->origin[1], light->origin[2]
502                                                 , nl->origin[0], nl->origin[1], nl->origin[2]
503                                                 , ent->inversematrix.m[0][0], ent->inversematrix.m[0][1], ent->inversematrix.m[0][2], ent->inversematrix.m[0][3]
504                                                 , ent->inversematrix.m[1][0], ent->inversematrix.m[1][1], ent->inversematrix.m[1][2], ent->inversematrix.m[1][3]
505                                                 , ent->inversematrix.m[2][0], ent->inversematrix.m[2][1], ent->inversematrix.m[2][2], ent->inversematrix.m[2][3]
506                                                 , ent->inversematrix.m[3][0], ent->inversematrix.m[3][1], ent->inversematrix.m[3][2], ent->inversematrix.m[3][3]);
507                                                 */
508                                         }
509                                         // integrate mscale into falloff, for maximum speed
510                                         nl->falloff = mscale;
511                                         VectorCopy(ambientcolor, nl->ambientlight);
512                                         nl->light[0] = light->rtlight.lightmap_light[0] * colorr * 4.0f;
513                                         nl->light[1] = light->rtlight.lightmap_light[1] * colorg * 4.0f;
514                                         nl->light[2] = light->rtlight.lightmap_light[2] * colorb * 4.0f;
515                                         nl->subtract = light->rtlight.lightmap_subtract;
516                                         nl->offset = LIGHTOFFSET;
517                                 }
518                         }
519                 }
520         }
521         ambient4f[0] *= colorr;
522         ambient4f[1] *= colorg;
523         ambient4f[2] *= colorb;
524         ambient4f[3] = colora;
525         diffusecolor[0] *= colorr;
526         diffusecolor[1] *= colorg;
527         diffusecolor[2] *= colorb;
528         return nearlights != 0 || DotProduct(diffusecolor, diffusecolor) > 0;
529 }
530
531 void R_LightModel_CalcVertexColors(const float *ambientcolor4f, const float *diffusecolor, const float *diffusenormal, int numverts, const float *vertex3f, const float *normal3f, float *color4f)
532 {
533         int i, j, usediffuse;
534         float color[4], v[3], dot, dist2, f, dnormal[3];
535         nearlight_t *nl;
536         usediffuse = DotProduct(diffusecolor, diffusecolor) > 0;
537         // negate the diffuse normal to avoid the need to negate the
538         // dotproduct on each vertex
539         VectorNegate(diffusenormal, dnormal);
540         if (usediffuse)
541                 VectorNormalize(dnormal);
542         // directional shading code here
543         for (i = 0;i < numverts;i++, vertex3f += 3, normal3f += 3, color4f += 4)
544         {
545                 VectorCopy4(ambientcolor4f, color);
546
547                 // silly directional diffuse shading
548                 if (usediffuse)
549                 {
550                         dot = DotProduct(normal3f, dnormal);
551                         if (dot > 0)
552                                 VectorMA(color, dot, diffusecolor, color);
553                 }
554
555                 // pretty good lighting
556                 for (j = 0, nl = &nearlight[0];j < nearlights;j++, nl++)
557                 {
558                         VectorSubtract(vertex3f, nl->origin, v);
559                         // first eliminate negative lighting (back side)
560                         dot = DotProduct(normal3f, v);
561                         if (dot > 0)
562                         {
563                                 // we'll need this again later to normalize the dotproduct
564                                 dist2 = DotProduct(v,v);
565                                 // do the distance attenuation math
566                                 f = (1.0f / (dist2 * nl->falloff + nl->offset)) - nl->subtract;
567                                 if (f > 0)
568                                 {
569                                         // we must divide dot by sqrt(dist2) to compensate for
570                                         // the fact we did not normalize v before doing the
571                                         // dotproduct, the result is in the range 0 to 1 (we
572                                         // eliminated negative numbers already)
573                                         f *= dot / sqrt(dist2);
574                                         // blend in the lighting
575                                         VectorMA(color, f, nl->light, color);
576                                 }
577                         }
578                 }
579                 VectorCopy4(color, color4f);
580         }
581 }
582
583 void R_UpdateEntLights(entity_render_t *ent)
584 {
585         int i;
586         const mlight_t *sl;
587         vec3_t v;
588         if (r_shadow_realtime_world.integer && r_shadow_realtime_world_lightmaps.value <= 0)
589                 return;
590         VectorSubtract(ent->origin, ent->entlightsorigin, v);
591         if (ent->entlightsframe != (r_framecount - 1) || (realtime > ent->entlightstime && DotProduct(v,v) >= 1.0f))
592         {
593                 ent->entlightstime = realtime + 0.1;
594                 VectorCopy(ent->origin, ent->entlightsorigin);
595                 ent->numentlights = 0;
596                 if (cl.worldmodel)
597                         for (i = 0, sl = cl.worldmodel->brushq1.lights;i < cl.worldmodel->brushq1.numlights && ent->numentlights < MAXENTLIGHTS;i++, sl++)
598                                 if (CL_TraceLine(ent->origin, sl->origin, NULL, NULL, false, NULL, SUPERCONTENTS_SOLID) == 1)
599                                         ent->entlights[ent->numentlights++] = i;
600         }
601         ent->entlightsframe = r_framecount;
602 }
603