src/mesa/tnl/t_vb_light.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "c99_math.h"
  27 #include "main/glheader.h"
  28 #include "main/light.h"
  29 #include "main/macros.h"
  30 #include "util/imports.h"
  31 #include "util/simple_list.h"
  32 #include "main/mtypes.h"
  33
  34 #include "math/m_translate.h"
  35
  36 #include "util/bitscan.h"
  37
  38 #include "t_context.h"
  39 #include "t_pipeline.h"
  40 #include "tnl.h"
  41
  42 #define LIGHT_TWOSIDE       0x1
  43 #define LIGHT_MATERIAL      0x2
  44 #define MAX_LIGHT_FUNC      0x4
  45
  46 typedef void (*light_func)( struct gl_context *ctx,
  47                             struct vertex_buffer *VB,
  48                             struct tnl_pipeline_stage *stage,
  49                             GLvector4f *input );
  50
  51 /**
  52  * Information for updating current material attributes from vertex color,
  53  * for GL_COLOR_MATERIAL.
  54  */
  55 struct material_cursor {
  56    const GLfloat *ptr;    /* points to src vertex color (in VB array) */
  57    GLuint stride;         /* stride to next vertex color (bytes) */
  58    GLfloat *current;      /* points to material attribute to update */
  59    GLuint size;           /* vertex/color size: 1, 2, 3 or 4 */
  60 };
  61
  62 /**
  63  * Data private to this pipeline stage.
  64  */
  65 struct light_stage_data {
  66    GLvector4f Input;
  67    GLvector4f LitColor[2];
  68    GLvector4f LitSecondary[2];
  69    light_func *light_func_tab;
  70
  71    struct material_cursor mat[MAT_ATTRIB_MAX];
  72    GLuint mat_count;
  73    GLuint mat_bitmask;
  74 };
  75
  76
  77 #define LIGHT_STAGE_DATA(stage) ((struct light_stage_data *)(stage->privatePtr))
  78
  79
  80
  81 /**********************************************************************/
  82 /*****                  Lighting computation                      *****/
  83 /**********************************************************************/
  84
  85
  86 /*
  87  * Notes:
  88  *   When two-sided lighting is enabled we compute the color (or index)
  89  *   for both the front and back side of the primitive.  Then, when the
  90  *   orientation of the facet is later learned, we can determine which
  91  *   color (or index) to use for rendering.
  92  *
  93  *   KW: We now know orientation in advance and only shade for
  94  *       the side or sides which are actually required.
  95  *
  96  * Variables:
  97  *   n = normal vector
  98  *   V = vertex position
  99  *   P = light source position
 100  *   Pe = (0,0,0,1)
 101  *
 102  * Precomputed:
 103  *   IF P[3]==0 THEN
 104  *       // light at infinity
 105  *       IF local_viewer THEN
 106  *           _VP_inf_norm = unit vector from V to P      // Precompute
 107  *       ELSE
 108  *           // eye at infinity
 109  *           _h_inf_norm = Normalize( VP + <0,0,1> )     // Precompute
 110  *       ENDIF
 111  *   ENDIF
 112  *
 113  * Functions:
 114  *   Normalize( v ) = normalized vector v
 115  *   Magnitude( v ) = length of vector v
 116  */
 117
 118
 119
 120 static void
 121 validate_shine_table( struct gl_context *ctx, GLuint side, GLfloat shininess )
 122 {
 123    TNLcontext *tnl = TNL_CONTEXT(ctx);
 124    struct tnl_shine_tab *list = tnl->_ShineTabList;
 125    struct tnl_shine_tab *s;
 126
 127    assert(side < 2);
 128
 129    foreach(s, list)
 130       if ( s->shininess == shininess )
 131          break;
 132
 133    if (s == list) {
 134       GLint j;
 135       GLfloat *m;
 136
 137       foreach(s, list)
 138          if (s->refcount == 0)
 139             break;
 140
 141       m = s->tab;
 142       m[0] = 0.0F;
 143       if (shininess == 0.0F) {
 144          for (j = 1 ; j <= SHINE_TABLE_SIZE ; j++)
 145             m[j] = 1.0F;
 146       }
 147       else {
 148          for (j = 1 ; j < SHINE_TABLE_SIZE ; j++) {
 149             GLfloat t, x = j / (GLfloat) (SHINE_TABLE_SIZE - 1);
 150             if (x < 0.005F) /* underflow check */
 151                x = 0.005F;
 152             t = powf(x, shininess);
 153             if (t > 1e-20F)
 154                m[j] = t;
 155             else
 156                m[j] = 0.0F;
 157          }
 158          m[SHINE_TABLE_SIZE] = 1.0F;
 159       }
 160
 161       s->shininess = shininess;
 162    }
 163
 164    if (tnl->_ShineTable[side])
 165       tnl->_ShineTable[side]->refcount--;
 166
 167    tnl->_ShineTable[side] = s;
 168    move_to_tail( list, s );
 169    s->refcount++;
 170 }
 171
 172
 173 void
 174 _tnl_validate_shine_tables( struct gl_context *ctx )
 175 {
 176    TNLcontext *tnl = TNL_CONTEXT(ctx);
 177    GLfloat shininess;
 178
 179    shininess = ctx->Light.Material.Attrib[MAT_ATTRIB_FRONT_SHININESS][0];
 180    if (!tnl->_ShineTable[0] || tnl->_ShineTable[0]->shininess != shininess)
 181       validate_shine_table( ctx, 0, shininess );
 182
 183    shininess = ctx->Light.Material.Attrib[MAT_ATTRIB_BACK_SHININESS][0];
 184    if (!tnl->_ShineTable[1] || tnl->_ShineTable[1]->shininess != shininess)
 185       validate_shine_table( ctx, 1, shininess );
 186 }
 187
 188
 189 /**
 190  * In the case of colormaterial, the effected material attributes
 191  * should already have been bound to point to the incoming color data,
 192  * prior to running the pipeline.
 193  * This function copies the vertex's color to the material attributes
 194  * which are tracking glColor.
 195  * It's called per-vertex in the lighting loop.
 196  */
 197 static void
 198 update_materials(struct gl_context *ctx, struct light_stage_data *store)
 199 {
 200    GLuint i;
 201
 202    for (i = 0 ; i < store->mat_count ; i++) {
 203       /* update the material */
 204       COPY_CLEAN_4V(store->mat[i].current, store->mat[i].size, store->mat[i].ptr);
 205       /* increment src vertex color pointer */
 206       STRIDE_F(store->mat[i].ptr, store->mat[i].stride);
 207    }
 208
 209    /* recompute derived light/material values */
 210    _mesa_update_material( ctx, store->mat_bitmask );
 211    /* XXX we should only call this if we're tracking/changing the specular
 212     * exponent.
 213     */
 214    _tnl_validate_shine_tables( ctx );
 215 }
 216
 217
 218 /**
 219  * Prepare things prior to running the lighting stage.
 220  * Return number of material attributes which will track vertex color.
 221  */
 222 static GLuint
 223 prepare_materials(struct gl_context *ctx,
 224                   struct vertex_buffer *VB, struct light_stage_data *store)
 225 {
 226    GLuint i;
 227
 228    store->mat_count = 0;
 229    store->mat_bitmask = 0;
 230
 231    /* Examine the _ColorMaterialBitmask to determine which materials
 232     * track vertex color.  Override the material attribute's pointer
 233     * with the color pointer for each one.
 234     */
 235    if (ctx->Light.ColorMaterialEnabled) {
 236       GLbitfield bitmask = ctx->Light._ColorMaterialBitmask;
 237       while (bitmask) {
 238          const int i = u_bit_scan(&bitmask);
 239          VB->AttribPtr[_TNL_ATTRIB_MAT_FRONT_AMBIENT + i] =
 240             VB->AttribPtr[_TNL_ATTRIB_COLOR0];
 241       }
 242    }
 243
 244    /* Now, for each material attribute that's tracking vertex color, save
 245     * some values (ptr, stride, size, current) that we'll need in
 246     * update_materials(), above, that'll actually copy the vertex color to
 247     * the material attribute(s).
 248     */
 249    for (i = _TNL_FIRST_MAT; i <= _TNL_LAST_MAT; i++) {
 250       if (VB->AttribPtr[i]->stride) {
 251          const GLuint j = store->mat_count++;
 252          const GLuint attr = i - _TNL_ATTRIB_MAT_FRONT_AMBIENT;
 253          store->mat[j].ptr    = VB->AttribPtr[i]->start;
 254          store->mat[j].stride = VB->AttribPtr[i]->stride;
 255          store->mat[j].size   = VB->AttribPtr[i]->size;
 256          store->mat[j].current = ctx->Light.Material.Attrib[attr];
 257          store->mat_bitmask |= (1<<attr);
 258       }
 259    }
 260
 261    /* FIXME: Is this already done?
 262     */
 263    _mesa_update_material( ctx, ~0 );
 264
 265    _tnl_validate_shine_tables( ctx );
 266
 267    return store->mat_count;
 268 }
 269
 270 /*
 271  * Compute dp ^ SpecularExponent.
 272  * Lerp between adjacent values in the f(x) lookup table, giving a
 273  * continuous function, with adequate overall accuracy.  (Though still
 274  * pretty good compared to a straight lookup).
 275  */
 276 static inline GLfloat
 277 lookup_shininess(const struct gl_context *ctx, GLuint face, GLfloat dp)
 278 {
 279    TNLcontext *tnl = TNL_CONTEXT(ctx);
 280    const struct tnl_shine_tab *tab = tnl->_ShineTable[face];
 281    float f = dp * (SHINE_TABLE_SIZE - 1);
 282    int k = (int) f;
 283    if (k < 0 /* gcc may cast an overflow float value to negative int value */
 284         || k > SHINE_TABLE_SIZE - 2)
 285       return powf(dp, tab->shininess);
 286    else
 287       return tab->tab[k] + (f - k) * (tab->tab[k+1] - tab->tab[k]);
 288 }
 289
 290 /* Tables for all the shading functions.
 291  */
 292 static light_func _tnl_light_tab[MAX_LIGHT_FUNC];
 293 static light_func _tnl_light_fast_tab[MAX_LIGHT_FUNC];
 294 static light_func _tnl_light_fast_single_tab[MAX_LIGHT_FUNC];
 295 static light_func _tnl_light_spec_tab[MAX_LIGHT_FUNC];
 296
 297 #define TAG(x)           x
 298 #define IDX              (0)
 299 #include "t_vb_lighttmp.h"
 300
 301 #define TAG(x)           x##_twoside
 302 #define IDX              (LIGHT_TWOSIDE)
 303 #include "t_vb_lighttmp.h"
 304
 305 #define TAG(x)           x##_material
 306 #define IDX              (LIGHT_MATERIAL)
 307 #include "t_vb_lighttmp.h"
 308
 309 #define TAG(x)           x##_twoside_material
 310 #define IDX              (LIGHT_TWOSIDE|LIGHT_MATERIAL)
 311 #include "t_vb_lighttmp.h"
 312
 313
 314 static void init_lighting_tables( void )
 315 {
 316    static int done;
 317
 318    if (!done) {
 319       init_light_tab();
 320       init_light_tab_twoside();
 321       init_light_tab_material();
 322       init_light_tab_twoside_material();
 323       done = 1;
 324    }
 325 }
 326
 327
 328 static GLboolean run_lighting( struct gl_context *ctx,
 329                                struct tnl_pipeline_stage *stage )
 330 {
 331    struct light_stage_data *store = LIGHT_STAGE_DATA(stage);
 332    TNLcontext *tnl = TNL_CONTEXT(ctx);
 333    struct vertex_buffer *VB = &tnl->vb;
 334    GLvector4f *input = ctx->_NeedEyeCoords ? VB->EyePtr : VB->AttribPtr[_TNL_ATTRIB_POS];
 335    GLuint idx;
 336
 337    if (!ctx->Light.Enabled || ctx->VertexProgram._Current)
 338       return GL_TRUE;
 339
 340    /* Make sure we can talk about position x,y and z:
 341     */
 342    if (input->size <= 2 && input == VB->AttribPtr[_TNL_ATTRIB_POS]) {
 343
 344       _math_trans_4f( store->Input.data,
 345                       VB->AttribPtr[_TNL_ATTRIB_POS]->data,
 346                       VB->AttribPtr[_TNL_ATTRIB_POS]->stride,
 347                       GL_FLOAT,
 348                       VB->AttribPtr[_TNL_ATTRIB_POS]->size,
 349                       0,
 350                       VB->Count );
 351
 352       if (input->size <= 2) {
 353          /* Clean z.
 354           */
 355          _mesa_vector4f_clean_elem(&store->Input, VB->Count, 2);
 356       }
 357
 358       if (input->size <= 1) {
 359          /* Clean y.
 360           */
 361          _mesa_vector4f_clean_elem(&store->Input, VB->Count, 1);
 362       }
 363
 364       input = &store->Input;
 365    }
 366
 367    idx = 0;
 368
 369    if (prepare_materials( ctx, VB, store ))
 370       idx |= LIGHT_MATERIAL;
 371
 372    if (ctx->Light.Model.TwoSide)
 373       idx |= LIGHT_TWOSIDE;
 374
 375    /* The individual functions know about replaying side-effects
 376     * vs. full re-execution.
 377     */
 378    store->light_func_tab[idx]( ctx, VB, stage, input );
 379
 380    return GL_TRUE;
 381 }
 382
 383
 384 /* Called in place of do_lighting when the light table may have changed.
 385  */
 386 static void validate_lighting( struct gl_context *ctx,
 387                                         struct tnl_pipeline_stage *stage )
 388 {
 389    light_func *tab;
 390
 391    if (!ctx->Light.Enabled || ctx->VertexProgram._Current)
 392       return;
 393
 394    if (ctx->Light._NeedVertices) {
 395       if (ctx->Light.Model.ColorControl == GL_SEPARATE_SPECULAR_COLOR)
 396          tab = _tnl_light_spec_tab;
 397       else
 398          tab = _tnl_light_tab;
 399    }
 400    else {
 401       /* Power of two means only a single active light. */
 402       if (_mesa_is_pow_two(ctx->Light._EnabledLights))
 403          tab = _tnl_light_fast_single_tab;
 404       else
 405          tab = _tnl_light_fast_tab;
 406    }
 407
 408
 409    LIGHT_STAGE_DATA(stage)->light_func_tab = tab;
 410
 411    /* This and the above should only be done on _NEW_LIGHT:
 412     */
 413    TNL_CONTEXT(ctx)->Driver.NotifyMaterialChange( ctx );
 414 }
 415
 416
 417
 418 /* Called the first time stage->run is called.  In effect, don't
 419  * allocate data until the first time the stage is run.
 420  */
 421 static GLboolean init_lighting( struct gl_context *ctx,
 422                                 struct tnl_pipeline_stage *stage )
 423 {
 424    TNLcontext *tnl = TNL_CONTEXT(ctx);
 425    struct light_stage_data *store;
 426    GLuint size = tnl->vb.Size;
 427
 428    stage->privatePtr = malloc(sizeof(*store));
 429    store = LIGHT_STAGE_DATA(stage);
 430    if (!store)
 431       return GL_FALSE;
 432
 433    /* Do onetime init.
 434     */
 435    init_lighting_tables();
 436
 437    _mesa_vector4f_alloc( &store->Input, 0, size, 32 );
 438    _mesa_vector4f_alloc( &store->LitColor[0], 0, size, 32 );
 439    _mesa_vector4f_alloc( &store->LitColor[1], 0, size, 32 );
 440    _mesa_vector4f_alloc( &store->LitSecondary[0], 0, size, 32 );
 441    _mesa_vector4f_alloc( &store->LitSecondary[1], 0, size, 32 );
 442
 443    store->LitColor[0].size = 4;
 444    store->LitColor[1].size = 4;
 445    store->LitSecondary[0].size = 3;
 446    store->LitSecondary[1].size = 3;
 447
 448    return GL_TRUE;
 449 }
 450
 451
 452
 453
 454 static void dtr( struct tnl_pipeline_stage *stage )
 455 {
 456    struct light_stage_data *store = LIGHT_STAGE_DATA(stage);
 457
 458    if (store) {
 459       _mesa_vector4f_free( &store->Input );
 460       _mesa_vector4f_free( &store->LitColor[0] );
 461       _mesa_vector4f_free( &store->LitColor[1] );
 462       _mesa_vector4f_free( &store->LitSecondary[0] );
 463       _mesa_vector4f_free( &store->LitSecondary[1] );
 464       free( store );
 465       stage->privatePtr = NULL;
 466    }
 467 }
 468
 469 const struct tnl_pipeline_stage _tnl_lighting_stage =
 470 {
 471    "lighting",                  /* name */
 472    NULL,                        /* private_data */
 473    init_lighting,
 474    dtr,                         /* destroy */
 475    validate_lighting,
 476    run_lighting
 477 };