r_shadow.c

   1
   2 #include "quakedef.h"
   3 #include "r_shadow.h"
   4
   5 mempool_t *r_shadow_mempool;
   6
   7 int maxshadowelements;
   8 int *shadowelements;
   9 int maxtrianglefacinglight;
  10 qbyte *trianglefacinglight;
  11
  12 rtexturepool_t *r_shadow_texturepool;
  13 rtexture_t *r_shadow_attenuationtexture;
  14
  15 cvar_t r_shadow1 = {0, "r_shadow1", "16"};
  16 cvar_t r_shadow2 = {0, "r_shadow2", "2"};
  17 cvar_t r_shadow3 = {0, "r_shadow3", "65536"};
  18 cvar_t r_shadow4 = {0, "r_shadow4", "1"};
  19 cvar_t r_shadow5 = {0, "r_shadow5", "0.05"};
  20 cvar_t r_shadow6 = {0, "r_shadow6", "1"};
  21
  22 void r_shadow_start(void)
  23 {
  24         // allocate vertex processing arrays
  25         r_shadow_mempool = Mem_AllocPool("R_Shadow");
  26         maxshadowelements = 0;
  27         shadowelements = NULL;
  28         maxtrianglefacinglight = 0;
  29         trianglefacinglight = NULL;
  30         r_shadow_attenuationtexture = NULL;
  31         r_shadow_texturepool = NULL;
  32 }
  33
  34 void r_shadow_shutdown(void)
  35 {
  36         r_shadow_attenuationtexture = NULL;
  37         R_FreeTexturePool(&r_shadow_texturepool);
  38         maxshadowelements = 0;
  39         shadowelements = NULL;
  40         maxtrianglefacinglight = 0;
  41         trianglefacinglight = NULL;
  42         Mem_FreePool(&r_shadow_mempool);
  43 }
  44
  45 void r_shadow_newmap(void)
  46 {
  47 }
  48
  49 void R_Shadow_Init(void)
  50 {
  51         Cvar_RegisterVariable(&r_shadow1);
  52         Cvar_RegisterVariable(&r_shadow2);
  53         Cvar_RegisterVariable(&r_shadow3);
  54         Cvar_RegisterVariable(&r_shadow4);
  55         Cvar_RegisterVariable(&r_shadow5);
  56         Cvar_RegisterVariable(&r_shadow6);
  57         R_RegisterModule("R_Shadow", r_shadow_start, r_shadow_shutdown, r_shadow_newmap);
  58 }
  59
  60 void R_Shadow_Volume(int numverts, int numtris, float *vertex, int *elements, int *neighbors, vec3_t relativelightorigin, float lightradius, float projectdistance, int visiblevolume)
  61 {
  62         int i, *e, *n, *out, tris;
  63         float *v0, *v1, *v2, temp[3], f;
  64         if (projectdistance < 0.1)
  65         {
  66                 Con_Printf("R_Shadow_Volume: projectdistance %f\n");
  67                 return;
  68         }
  69 // terminology:
  70 //
  71 // frontface:
  72 // a triangle facing the light source
  73 //
  74 // backface:
  75 // a triangle not facing the light source
  76 //
  77 // shadow volume:
  78 // an extrusion of the backfaces, beginning at the original geometry and
  79 // ending further from the light source than the original geometry
  80 // (presumably at least as far as the light's radius, if the light has a
  81 // radius at all), capped at both front and back to avoid any problems
  82 //
  83 // description:
  84 // draws the shadow volumes of the model.
  85 // requirements:
  86 // vertex loations must already be in vertex before use.
  87 // vertex must have capacity for numverts * 2.
  88
  89         // make sure trianglefacinglight is big enough for this volume
  90         if (maxtrianglefacinglight < numtris)
  91         {
  92                 maxtrianglefacinglight = numtris;
  93                 if (trianglefacinglight)
  94                         Mem_Free(trianglefacinglight);
  95                 trianglefacinglight = Mem_Alloc(r_shadow_mempool, maxtrianglefacinglight);
  96         }
  97
  98         // make sure shadowelements is big enough for this volume
  99         if (maxshadowelements < numtris * 24)
 100         {
 101                 maxshadowelements = numtris * 24;
 102                 if (shadowelements)
 103                         Mem_Free(shadowelements);
 104                 shadowelements = Mem_Alloc(r_shadow_mempool, maxshadowelements * sizeof(int));
 105         }
 106
 107         // make projected vertices
 108         // by clever use of elements we'll construct the whole shadow from
 109         // the unprojected vertices and these projected vertices
 110         for (i = 0, v0 = vertex, v1 = vertex + numverts * 4;i < numverts;i++, v0 += 4, v1 += 4)
 111         {
 112                 VectorSubtract(v0, relativelightorigin, temp);
 113 #if 0
 114                 f = lightradius / sqrt(DotProduct(temp,temp));
 115                 if (f < 1)
 116                         f = 1;
 117                 VectorMA(relativelightorigin, f, temp, v1);
 118 #else
 119                 f = projectdistance / sqrt(DotProduct(temp,temp));
 120                 VectorMA(v0, f, temp, v1);
 121 #endif
 122         }
 123
 124         // check which triangles are facing the light
 125         for (i = 0, e = elements;i < numtris;i++, e += 3)
 126         {
 127                 // calculate triangle facing flag
 128                 v0 = vertex + e[0] * 4;
 129                 v1 = vertex + e[1] * 4;
 130                 v2 = vertex + e[2] * 4;
 131                 // we do not need to normalize the surface normal because both sides
 132                 // of the comparison use it, therefore they are both multiplied the
 133                 // same amount...  furthermore the subtract can be done on the
 134                 // vectors, saving a little bit of math in the dotproducts
 135 #if 1
 136                 // fast version
 137                 // subtracts v1 from v0 and v2, combined into a crossproduct,
 138                 // combined with a dotproduct of the light location relative to the
 139                 // first point of the triangle (any point works, since the triangle
 140                 // is obviously flat), and finally a comparison to determine if the
 141                 // light is infront of the triangle (the goal of this statement)
 142                 trianglefacinglight[i] =
 143                    (relativelightorigin[0] - v0[0]) * ((v0[1] - v1[1]) * (v2[2] - v1[2]) - (v0[2] - v1[2]) * (v2[1] - v1[1]))
 144                  + (relativelightorigin[1] - v0[1]) * ((v0[2] - v1[2]) * (v2[0] - v1[0]) - (v0[0] - v1[0]) * (v2[2] - v1[2]))
 145                  + (relativelightorigin[2] - v0[2]) * ((v0[0] - v1[0]) * (v2[1] - v1[1]) - (v0[1] - v1[1]) * (v2[0] - v1[0])) > 0;
 146 #else
 147                 // readable version
 148                 {
 149                 float dir0[3], dir1[3];
 150
 151                 // calculate two mostly perpendicular edge directions
 152                 VectorSubtract(v0, v1, dir0);
 153                 VectorSubtract(v2, v1, dir1);
 154
 155                 // we have two edge directions, we can calculate a third vector from
 156                 // them, which is the direction of the surface normal (it's magnitude
 157                 // is not 1 however)
 158                 CrossProduct(dir0, dir1, temp);
 159
 160                 // this is entirely unnecessary, but kept for clarity
 161                 //VectorNormalize(temp);
 162
 163                 // compare distance of light along normal, with distance of any point
 164                 // of the triangle along the same normal (the triangle is planar,
 165                 // I.E. flat, so all points give the same answer)
 166                 // the normal is not normalized because it is used on both sides of
 167                 // the comparison, so it's magnitude does not matter
 168                 trianglefacinglight[i] = DotProduct(relativelightorigin, temp) >= DotProduct(v0, temp);
 169 #endif
 170         }
 171
 172         // output triangle elements
 173         out = shadowelements;
 174         tris = 0;
 175
 176         // check each backface for bordering frontfaces,
 177         // and cast shadow polygons from those edges,
 178         // also create front and back caps for shadow volume
 179         for (i = 0, e = elements, n = neighbors;i < numtris;i++, e += 3, n += 3)
 180         {
 181                 if (!trianglefacinglight[i])
 182                 {
 183                         // triangle is backface and therefore casts shadow,
 184                         // output front and back caps for shadow volume
 185 #if 1
 186                         // front cap (with flipped winding order)
 187                         out[0] = e[0];
 188                         out[1] = e[2];
 189                         out[2] = e[1];
 190                         // rear cap
 191                         out[3] = e[0] + numverts;
 192                         out[4] = e[1] + numverts;
 193                         out[5] = e[2] + numverts;
 194                         out += 6;
 195                         tris += 2;
 196 #else
 197                         // rear cap
 198                         out[0] = e[0] + numverts;
 199                         out[1] = e[1] + numverts;
 200                         out[2] = e[2] + numverts;
 201                         out += 3;
 202                         tris += 1;
 203 #endif
 204                         // check the edges
 205                         if (n[0] < 0 || trianglefacinglight[n[0]])
 206                         {
 207                                 out[0] = e[0];
 208                                 out[1] = e[1];
 209                                 out[2] = e[1] + numverts;
 210                                 out[3] = e[0];
 211                                 out[4] = e[1] + numverts;
 212                                 out[5] = e[0] + numverts;
 213                                 out += 6;
 214                                 tris += 2;
 215                         }
 216                         if (n[1] < 0 || trianglefacinglight[n[1]])
 217                         {
 218                                 out[0] = e[1];
 219                                 out[1] = e[2];
 220                                 out[2] = e[2] + numverts;
 221                                 out[3] = e[1];
 222                                 out[4] = e[2] + numverts;
 223                                 out[5] = e[1] + numverts;
 224                                 out += 6;
 225                                 tris += 2;
 226                         }
 227                         if (n[2] < 0 || trianglefacinglight[n[2]])
 228                         {
 229                                 out[0] = e[2];
 230                                 out[1] = e[0];
 231                                 out[2] = e[0] + numverts;
 232                                 out[3] = e[2];
 233                                 out[4] = e[0] + numverts;
 234                                 out[5] = e[2] + numverts;
 235                                 out += 6;
 236                                 tris += 2;
 237                         }
 238                 }
 239         }
 240         R_Shadow_RenderVolume(numverts * 2, tris, shadowelements, visiblevolume);
 241 }
 242
 243 void R_Shadow_RenderVolume(int numverts, int numtris, int *elements, int visiblevolume)
 244 {
 245         // draw the volume
 246         if (visiblevolume)
 247         {
 248                 qglDisable(GL_CULL_FACE);
 249                 R_Mesh_Draw(numverts, numtris, elements);
 250                 qglEnable(GL_CULL_FACE);
 251         }
 252         else
 253         {
 254                 // increment stencil if backface is behind depthbuffer
 255                 qglCullFace(GL_BACK); // quake is backwards, this culls front faces
 256                 qglStencilOp(GL_KEEP, GL_INCR, GL_KEEP);
 257                 R_Mesh_Draw(numverts, numtris, elements);
 258                 // decrement stencil if frontface is behind depthbuffer
 259                 qglCullFace(GL_FRONT); // quake is backwards, this culls back faces
 260                 qglStencilOp(GL_KEEP, GL_DECR, GL_KEEP);
 261                 R_Mesh_Draw(numverts, numtris, elements);
 262         }
 263 }
 264
 265 float r_shadow_atten1, r_shadow_atten2, r_shadow_atten5;
 266 static void R_Shadow_MakeTextures(void)
 267 {
 268         int x, y, z, d;
 269         float v[3];
 270         qbyte data[32][32][32][4];
 271         R_FreeTexturePool(&r_shadow_texturepool);
 272         r_shadow_texturepool = R_AllocTexturePool();
 273         r_shadow_atten1 = r_shadow1.value;
 274         r_shadow_atten2 = r_shadow2.value;
 275         r_shadow_atten5 = r_shadow5.value;
 276         for (z = 0;z < 32;z++)
 277         {
 278                 for (y = 0;y < 32;y++)
 279                 {
 280                         for (x = 0;x < 32;x++)
 281                         {
 282                                 v[0] = (x / 32.0f) - 0.5f;
 283                                 v[1] = (y / 32.0f) - 0.5f;
 284                                 v[2] = (z / 32.0f) - 0.5f;
 285                                 d = (int) (((r_shadow_atten1 / (DotProduct(v, v)+r_shadow_atten5)) - (r_shadow_atten1 * r_shadow_atten2)));
 286                                 d = bound(0, d, 255);
 287                                 data[z][y][x][0] = data[z][y][x][1] = data[z][y][x][2] = data[z][y][x][3] = d;
 288                         }
 289                 }
 290         }
 291         r_shadow_attenuationtexture = R_LoadTexture3D(r_shadow_texturepool, "attenuation", 32, 32, 32, &data[0][0][0][0], TEXTYPE_RGBA, TEXF_PRECACHE | TEXF_ALPHA);
 292         qglTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP);
 293         qglTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 294         qglTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP);
 295 }
 296
 297 void R_Shadow_Stage_Depth(void)
 298 {
 299         rmeshstate_t m;
 300
 301         //cl.worldmodel->numlights = min(cl.worldmodel->numlights, 1);
 302         if (!r_shadow_attenuationtexture || r_shadow1.value != r_shadow_atten1 || r_shadow2.value != r_shadow_atten2 || r_shadow5.value != r_shadow_atten5)
 303                 R_Shadow_MakeTextures();
 304
 305         memset(&m, 0, sizeof(m));
 306         m.blendfunc1 = GL_ONE;
 307         m.blendfunc2 = GL_ZERO;
 308         R_Mesh_State(&m);
 309         GL_Color(0, 0, 0, 1);
 310 }
 311
 312 void R_Shadow_Stage_ShadowVolumes(void)
 313 {
 314         rmeshstate_t m;
 315         memset(&m, 0, sizeof(m));
 316         R_Mesh_TextureState(&m);
 317         GL_Color(1, 1, 1, 1);
 318         qglColorMask(0, 0, 0, 0);
 319         qglDisable(GL_BLEND);
 320         qglDepthMask(0);
 321         qglDepthFunc(GL_LEQUAL);
 322         qglClearStencil(0);
 323         qglClear(GL_STENCIL_BUFFER_BIT);
 324         qglEnable(GL_STENCIL_TEST);
 325         qglStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 326         qglStencilFunc(GL_ALWAYS, 0, 0xFF);
 327 }
 328
 329 void R_Shadow_Stage_Light(void)
 330 {
 331         rmeshstate_t m;
 332         memset(&m, 0, sizeof(m));
 333         if (r_shadow6.integer)
 334                 m.tex3d[0] = R_GetTexture(r_shadow_attenuationtexture);
 335         R_Mesh_TextureState(&m);
 336         qglEnable(GL_BLEND);
 337         qglBlendFunc(GL_ONE, GL_ONE);
 338         GL_Color(1, 1, 1, 1);
 339         qglColorMask(1, 1, 1, 1);
 340         qglDepthMask(0);
 341         qglDepthFunc(GL_EQUAL);
 342         qglEnable(GL_STENCIL_TEST);
 343         qglStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 344         // only draw light where this geometry was already rendered AND the
 345         // stencil is 0 (non-zero means shadow)
 346         qglStencilFunc(GL_EQUAL, 0, 0xFF);
 347 }
 348
 349 void R_Shadow_Stage_Textures(void)
 350 {
 351         rmeshstate_t m;
 352         // attempt to restore state to what Mesh_State thinks it is
 353         qglDisable(GL_BLEND);
 354         qglBlendFunc(GL_ONE, GL_ZERO);
 355         qglDepthMask(1);
 356
 357         // now change to a more useful state
 358         memset(&m, 0, sizeof(m));
 359         m.blendfunc1 = GL_DST_COLOR;
 360         m.blendfunc2 = GL_SRC_COLOR;
 361         R_Mesh_State(&m);
 362
 363         // now hack some more
 364         GL_Color(1, 1, 1, 1);
 365         qglColorMask(1, 1, 1, 1);
 366         qglDepthFunc(GL_EQUAL);
 367         qglEnable(GL_STENCIL_TEST);
 368         qglStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 369         // only draw in lit areas
 370         qglStencilFunc(GL_EQUAL, 0, 0xFF);
 371 }
 372
 373 void R_Shadow_Stage_End(void)
 374 {
 375         rmeshstate_t m;
 376         GL_Color(1, 1, 1, 1);
 377         qglColorMask(1, 1, 1, 1);
 378         qglDepthFunc(GL_LEQUAL);
 379         qglDisable(GL_STENCIL_TEST);
 380         qglStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 381         qglStencilFunc(GL_ALWAYS, 0, 0xFF);
 382
 383         // now change to a more useful state
 384         memset(&m, 0, sizeof(m));
 385         m.blendfunc1 = GL_ONE;
 386         m.blendfunc2 = GL_ZERO;
 387         R_Mesh_State(&m);
 388 }
 389
 390 void R_Shadow_Light(int numverts, float *normals, vec3_t relativelightorigin, float lightradius, float lightdistbias, float lightsubtract, float *lightcolor)
 391 {
 392         if (!r_shadow6.integer)
 393         {
 394                 int i;
 395                 float *n, *v, *c, f, dist, temp[3], light[3], lightradius2;
 396                 VectorCopy(lightcolor, light);
 397                 lightradius2 = lightradius * lightradius;
 398                 for (i = 0, v = varray_vertex, c = varray_color, n = normals;i < numverts;i++, v += 4, c += 4, n += 3)
 399                 {
 400                         VectorSubtract(relativelightorigin, v, temp);
 401                         c[0] = 0;
 402                         c[1] = 0;
 403                         c[2] = 0;
 404                         c[3] = 1;
 405                         f = DotProduct(n, temp);
 406                         if (f > 0)
 407                         {
 408                                 dist = DotProduct(temp, temp);
 409                                 if (dist < lightradius2)
 410                                 {
 411                                         f = ((1.0f / (dist + lightdistbias)) - lightsubtract) * (f / sqrt(dist));
 412                                         c[0] = f * light[0];
 413                                         c[1] = f * light[1];
 414                                         c[2] = f * light[2];
 415                                 }
 416                         }
 417                 }
 418         }
 419         else
 420         {
 421                 int i;
 422                 float *n, *v, *c, *t, f, temp[3], light[3], iradius, attentexbase[3];
 423                 VectorScale(lightcolor, (1.0f / r_shadow3.value), light);
 424                 iradius = 0.5f / lightradius;
 425                 attentexbase[0] = 0.5f;
 426                 attentexbase[1] = 0.5f;
 427                 attentexbase[2] = 0.5f;
 428                 for (i = 0, v = varray_vertex, c = varray_color, n = normals, t = varray_texcoord[0];i < numverts;i++, v += 4, c += 4, n += 3, t += 4)
 429                 {
 430                         VectorSubtract(v, relativelightorigin, temp);
 431                         VectorMA(attentexbase, iradius, temp, t);
 432                         c[0] = 0;
 433                         c[1] = 0;
 434                         c[2] = 0;
 435                         c[3] = 1;
 436                         f = DotProduct(n, temp);
 437                         if (f < 0)
 438                         {
 439                                 f /= -sqrt(DotProduct(temp, temp));
 440                                 c[0] = f * light[0];
 441                                 c[1] = f * light[1];
 442                                 c[2] = f * light[2];
 443                         }
 444                 }
 445         }
 446 }