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