src/mesa/tnl/t_vb_light.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27
  28 #include "main/glheader.h"
  29 #include "main/colormac.h"
  30 #include "main/light.h"
  31 #include "main/macros.h"
  32 #include "main/imports.h"
  33 #include "main/simple_list.h"
  34 #include "main/mtypes.h"
  35
  36 #include "math/m_translate.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] = 0.0;
 143       if (shininess == 0.0) {
 144          for (j = 1 ; j <= SHINE_TABLE_SIZE ; j++)
 145             m[j] = 1.0;
 146       }
 147       else {
 148          for (j = 1 ; j < SHINE_TABLE_SIZE ; j++) {
 149             GLdouble t, x = j / (GLfloat) (SHINE_TABLE_SIZE - 1);
 150             if (x < 0.005) /* underflow check */
 151                x = 0.005;
 152             t = pow(x, shininess);
 153             if (t > 1e-20)
 154                m[j] = (GLfloat) t;
 155             else
 156                m[j] = 0.0;
 157          }
 158          m[SHINE_TABLE_SIZE] = 1.0;
 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       const GLuint bitmask = ctx->Light._ColorMaterialBitmask;
 237       for (i = 0 ; i < MAT_ATTRIB_MAX ; i++)
 238          if (bitmask & (1<<i))
 239             VB->AttribPtr[_TNL_ATTRIB_MAT_FRONT_AMBIENT + i] = VB->AttribPtr[_TNL_ATTRIB_COLOR0];
 240    }
 241
 242    /* Now, for each material attribute that's tracking vertex color, save
 243     * some values (ptr, stride, size, current) that we'll need in
 244     * update_materials(), above, that'll actually copy the vertex color to
 245     * the material attribute(s).
 246     */
 247    for (i = _TNL_FIRST_MAT; i <= _TNL_LAST_MAT; i++) {
 248       if (VB->AttribPtr[i]->stride) {
 249          const GLuint j = store->mat_count++;
 250          const GLuint attr = i - _TNL_ATTRIB_MAT_FRONT_AMBIENT;
 251          store->mat[j].ptr    = VB->AttribPtr[i]->start;
 252          store->mat[j].stride = VB->AttribPtr[i]->stride;
 253          store->mat[j].size   = VB->AttribPtr[i]->size;
 254          store->mat[j].current = ctx->Light.Material.Attrib[attr];
 255          store->mat_bitmask |= (1<<attr);
 256       }
 257    }
 258
 259    /* FIXME: Is this already done?
 260     */
 261    _mesa_update_material( ctx, ~0 );
 262
 263    _tnl_validate_shine_tables( ctx );
 264
 265    return store->mat_count;
 266 }
 267
 268 /*
 269  * Compute dp ^ SpecularExponent.
 270  * Lerp between adjacent values in the f(x) lookup table, giving a
 271  * continuous function, with adequate overall accuracy.  (Though still
 272  * pretty good compared to a straight lookup).
 273  */
 274 static inline GLfloat
 275 lookup_shininess(const struct gl_context *ctx, GLuint face, GLfloat dp)
 276 {
 277    TNLcontext *tnl = TNL_CONTEXT(ctx);
 278    const struct tnl_shine_tab *tab = tnl->_ShineTable[face];
 279    float f = dp * (SHINE_TABLE_SIZE - 1);
 280    int k = (int) f;
 281    if (k < 0 /* gcc may cast an overflow float value to negative int value */
 282         || k > SHINE_TABLE_SIZE - 2)
 283       return powf(dp, tab->shininess);
 284    else
 285       return tab->tab[k] + (f - k) * (tab->tab[k+1] - tab->tab[k]);
 286 }
 287
 288 /* Tables for all the shading functions.
 289  */
 290 static light_func _tnl_light_tab[MAX_LIGHT_FUNC];
 291 static light_func _tnl_light_fast_tab[MAX_LIGHT_FUNC];
 292 static light_func _tnl_light_fast_single_tab[MAX_LIGHT_FUNC];
 293 static light_func _tnl_light_spec_tab[MAX_LIGHT_FUNC];
 294
 295 #define TAG(x)           x
 296 #define IDX              (0)
 297 #include "t_vb_lighttmp.h"
 298
 299 #define TAG(x)           x##_twoside
 300 #define IDX              (LIGHT_TWOSIDE)
 301 #include "t_vb_lighttmp.h"
 302
 303 #define TAG(x)           x##_material
 304 #define IDX              (LIGHT_MATERIAL)
 305 #include "t_vb_lighttmp.h"
 306
 307 #define TAG(x)           x##_twoside_material
 308 #define IDX              (LIGHT_TWOSIDE|LIGHT_MATERIAL)
 309 #include "t_vb_lighttmp.h"
 310
 311
 312 static void init_lighting_tables( void )
 313 {
 314    static int done;
 315
 316    if (!done) {
 317       init_light_tab();
 318       init_light_tab_twoside();
 319       init_light_tab_material();
 320       init_light_tab_twoside_material();
 321       done = 1;
 322    }
 323 }
 324
 325
 326 static GLboolean run_lighting( struct gl_context *ctx,
 327                                struct tnl_pipeline_stage *stage )
 328 {
 329    struct light_stage_data *store = LIGHT_STAGE_DATA(stage);
 330    TNLcontext *tnl = TNL_CONTEXT(ctx);
 331    struct vertex_buffer *VB = &tnl->vb;
 332    GLvector4f *input = ctx->_NeedEyeCoords ? VB->EyePtr : VB->AttribPtr[_TNL_ATTRIB_POS];
 333    GLuint idx;
 334
 335    if (!ctx->Light.Enabled || ctx->VertexProgram._Current)
 336       return GL_TRUE;
 337
 338    /* Make sure we can talk about position x,y and z:
 339     */
 340    if (input->size <= 2 && input == VB->AttribPtr[_TNL_ATTRIB_POS]) {
 341
 342       _math_trans_4f( store->Input.data,
 343                       VB->AttribPtr[_TNL_ATTRIB_POS]->data,
 344                       VB->AttribPtr[_TNL_ATTRIB_POS]->stride,
 345                       GL_FLOAT,
 346                       VB->AttribPtr[_TNL_ATTRIB_POS]->size,
 347                       0,
 348                       VB->Count );
 349
 350       if (input->size <= 2) {
 351          /* Clean z.
 352           */
 353          _mesa_vector4f_clean_elem(&store->Input, VB->Count, 2);
 354       }
 355
 356       if (input->size <= 1) {
 357          /* Clean y.
 358           */
 359          _mesa_vector4f_clean_elem(&store->Input, VB->Count, 1);
 360       }
 361
 362       input = &store->Input;
 363    }
 364
 365    idx = 0;
 366
 367    if (prepare_materials( ctx, VB, store ))
 368       idx |= LIGHT_MATERIAL;
 369
 370    if (ctx->Light.Model.TwoSide)
 371       idx |= LIGHT_TWOSIDE;
 372
 373    /* The individual functions know about replaying side-effects
 374     * vs. full re-execution.
 375     */
 376    store->light_func_tab[idx]( ctx, VB, stage, input );
 377
 378    return GL_TRUE;
 379 }
 380
 381
 382 /* Called in place of do_lighting when the light table may have changed.
 383  */
 384 static void validate_lighting( struct gl_context *ctx,
 385                                         struct tnl_pipeline_stage *stage )
 386 {
 387    light_func *tab;
 388
 389    if (!ctx->Light.Enabled || ctx->VertexProgram._Current)
 390       return;
 391
 392    if (ctx->Light._NeedVertices) {
 393       if (ctx->Light.Model.ColorControl == GL_SEPARATE_SPECULAR_COLOR)
 394          tab = _tnl_light_spec_tab;
 395       else
 396          tab = _tnl_light_tab;
 397    }
 398    else {
 399       if (ctx->Light.EnabledList.next == ctx->Light.EnabledList.prev)
 400          tab = _tnl_light_fast_single_tab;
 401       else
 402          tab = _tnl_light_fast_tab;
 403    }
 404
 405
 406    LIGHT_STAGE_DATA(stage)->light_func_tab = tab;
 407
 408    /* This and the above should only be done on _NEW_LIGHT:
 409     */
 410    TNL_CONTEXT(ctx)->Driver.NotifyMaterialChange( ctx );
 411 }
 412
 413
 414
 415 /* Called the first time stage->run is called.  In effect, don't
 416  * allocate data until the first time the stage is run.
 417  */
 418 static GLboolean init_lighting( struct gl_context *ctx,
 419                                 struct tnl_pipeline_stage *stage )
 420 {
 421    TNLcontext *tnl = TNL_CONTEXT(ctx);
 422    struct light_stage_data *store;
 423    GLuint size = tnl->vb.Size;
 424
 425    stage->privatePtr = malloc(sizeof(*store));
 426    store = LIGHT_STAGE_DATA(stage);
 427    if (!store)
 428       return GL_FALSE;
 429
 430    /* Do onetime init.
 431     */
 432    init_lighting_tables();
 433
 434    _mesa_vector4f_alloc( &store->Input, 0, size, 32 );
 435    _mesa_vector4f_alloc( &store->LitColor[0], 0, size, 32 );
 436    _mesa_vector4f_alloc( &store->LitColor[1], 0, size, 32 );
 437    _mesa_vector4f_alloc( &store->LitSecondary[0], 0, size, 32 );
 438    _mesa_vector4f_alloc( &store->LitSecondary[1], 0, size, 32 );
 439
 440    store->LitColor[0].size = 4;
 441    store->LitColor[1].size = 4;
 442    store->LitSecondary[0].size = 3;
 443    store->LitSecondary[1].size = 3;
 444
 445    return GL_TRUE;
 446 }
 447
 448
 449
 450
 451 static void dtr( struct tnl_pipeline_stage *stage )
 452 {
 453    struct light_stage_data *store = LIGHT_STAGE_DATA(stage);
 454
 455    if (store) {
 456       _mesa_vector4f_free( &store->Input );
 457       _mesa_vector4f_free( &store->LitColor[0] );
 458       _mesa_vector4f_free( &store->LitColor[1] );
 459       _mesa_vector4f_free( &store->LitSecondary[0] );
 460       _mesa_vector4f_free( &store->LitSecondary[1] );
 461       free( store );
 462       stage->privatePtr = NULL;
 463    }
 464 }
 465
 466 const struct tnl_pipeline_stage _tnl_lighting_stage =
 467 {
 468    "lighting",                  /* name */
 469    NULL,                        /* private_data */
 470    init_lighting,
 471    dtr,                         /* destroy */
 472    validate_lighting,
 473    run_lighting
 474 };