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