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      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  * Authors:
     25  *    Brian Paul Keith Whitwell <keithw (at) vmware.com>
     26  */
     27 
     28 /*
     29  * Regarding GL_NV_texgen_reflection:
     30  *
     31  * Portions of this software may use or implement intellectual
     32  * property owned and licensed by NVIDIA Corporation. NVIDIA disclaims
     33  * any and all warranties with respect to such intellectual property,
     34  * including any use thereof or modifications thereto.
     35  */
     36 
     37 #include "main/glheader.h"
     38 #include "main/macros.h"
     39 #include "main/imports.h"
     40 #include "main/mtypes.h"
     41 
     42 #include "math/m_xform.h"
     43 
     44 #include "t_context.h"
     45 #include "t_pipeline.h"
     46 
     47 
     48 /***********************************************************************
     49  * Automatic texture coordinate generation (texgen) code.
     50  */
     51 
     52 
     53 struct texgen_stage_data;
     54 
     55 typedef void (*texgen_func)( struct gl_context *ctx,
     56 			     struct texgen_stage_data *store,
     57 			     GLuint unit);
     58 
     59 
     60 struct texgen_stage_data {
     61 
     62    /* Per-texunit derived state.
     63     */
     64    GLuint TexgenSize[MAX_TEXTURE_COORD_UNITS];
     65    texgen_func TexgenFunc[MAX_TEXTURE_COORD_UNITS];
     66 
     67    /* Temporary values used in texgen.
     68     */
     69    GLfloat (*tmp_f)[3];
     70    GLfloat *tmp_m;
     71 
     72    /* Buffered outputs of the stage.
     73     */
     74    GLvector4f texcoord[MAX_TEXTURE_COORD_UNITS];
     75 };
     76 
     77 
     78 #define TEXGEN_STAGE_DATA(stage) ((struct texgen_stage_data *)stage->privatePtr)
     79 
     80 
     81 
     82 static GLuint all_bits[5] = {
     83    0,
     84    VEC_SIZE_1,
     85    VEC_SIZE_2,
     86    VEC_SIZE_3,
     87    VEC_SIZE_4,
     88 };
     89 
     90 #define VEC_SIZE_FLAGS (VEC_SIZE_1|VEC_SIZE_2|VEC_SIZE_3|VEC_SIZE_4)
     91 
     92 #define TEXGEN_NEED_M            (TEXGEN_SPHERE_MAP)
     93 #define TEXGEN_NEED_F            (TEXGEN_SPHERE_MAP        | \
     94 				  TEXGEN_REFLECTION_MAP_NV)
     95 
     96 
     97 
     98 static void build_m3( GLfloat f[][3], GLfloat m[],
     99 		      const GLvector4f *normal,
    100 		      const GLvector4f *eye )
    101 {
    102    GLuint stride = eye->stride;
    103    GLfloat *coord = (GLfloat *)eye->start;
    104    GLuint count = eye->count;
    105    const GLfloat *norm = normal->start;
    106    GLuint i;
    107 
    108    for (i=0;i<count;i++,STRIDE_F(coord,stride),STRIDE_F(norm,normal->stride)) {
    109       GLfloat u[3], two_nu, fx, fy, fz;
    110       COPY_3V( u, coord );
    111       NORMALIZE_3FV( u );
    112       two_nu = 2.0F * DOT3(norm,u);
    113       fx = f[i][0] = u[0] - norm[0] * two_nu;
    114       fy = f[i][1] = u[1] - norm[1] * two_nu;
    115       fz = f[i][2] = u[2] - norm[2] * two_nu;
    116       m[i] = fx * fx + fy * fy + (fz + 1.0F) * (fz + 1.0F);
    117       if (m[i] != 0.0F) {
    118 	 m[i] = 0.5F * (1.0f / sqrtf(m[i]));
    119       }
    120    }
    121 }
    122 
    123 
    124 
    125 static void build_m2( GLfloat f[][3], GLfloat m[],
    126 		      const GLvector4f *normal,
    127 		      const GLvector4f *eye )
    128 {
    129    GLuint stride = eye->stride;
    130    GLfloat *coord = eye->start;
    131    GLuint count = eye->count;
    132 
    133    GLfloat *norm = normal->start;
    134    GLuint i;
    135 
    136    for (i=0;i<count;i++,STRIDE_F(coord,stride),STRIDE_F(norm,normal->stride)) {
    137       GLfloat u[3], two_nu, fx, fy, fz;
    138       COPY_2V( u, coord );
    139       u[2] = 0;
    140       NORMALIZE_3FV( u );
    141       two_nu = 2.0F * DOT3(norm,u);
    142       fx = f[i][0] = u[0] - norm[0] * two_nu;
    143       fy = f[i][1] = u[1] - norm[1] * two_nu;
    144       fz = f[i][2] = u[2] - norm[2] * two_nu;
    145       m[i] = fx * fx + fy * fy + (fz + 1.0F) * (fz + 1.0F);
    146       if (m[i] != 0.0F) {
    147 	 m[i] = 0.5F * (1.0f / sqrtf(m[i]));
    148       }
    149    }
    150 }
    151 
    152 
    153 
    154 typedef void (*build_m_func)( GLfloat f[][3],
    155 			      GLfloat m[],
    156 			      const GLvector4f *normal,
    157 			      const GLvector4f *eye );
    158 
    159 
    160 static build_m_func build_m_tab[5] = {
    161    NULL,
    162    NULL,
    163    build_m2,
    164    build_m3,
    165    build_m3
    166 };
    167 
    168 
    169 /* This is unusual in that we respect the stride of the output vector
    170  * (f).  This allows us to pass in either a texcoord vector4f, or a
    171  * temporary vector3f.
    172  */
    173 static void build_f3( GLfloat *f,
    174 		      GLuint fstride,
    175 		      const GLvector4f *normal,
    176 		      const GLvector4f *eye )
    177 {
    178    GLuint stride = eye->stride;
    179    GLfloat *coord = eye->start;
    180    GLuint count = eye->count;
    181 
    182    GLfloat *norm = normal->start;
    183    GLuint i;
    184 
    185    for (i=0;i<count;i++) {
    186       GLfloat u[3], two_nu;
    187       COPY_3V( u, coord );
    188       NORMALIZE_3FV( u );
    189       two_nu = 2.0F * DOT3(norm,u);
    190       f[0] = u[0] - norm[0] * two_nu;
    191       f[1] = u[1] - norm[1] * two_nu;
    192       f[2] = u[2] - norm[2] * two_nu;
    193       STRIDE_F(coord,stride);
    194       STRIDE_F(f,fstride);
    195       STRIDE_F(norm, normal->stride);
    196    }
    197 }
    198 
    199 
    200 static void build_f2( GLfloat *f,
    201 		      GLuint fstride,
    202 		      const GLvector4f *normal,
    203 		      const GLvector4f *eye )
    204 {
    205    GLuint stride = eye->stride;
    206    GLfloat *coord = eye->start;
    207    GLuint count = eye->count;
    208    GLfloat *norm = normal->start;
    209    GLuint i;
    210 
    211    for (i=0;i<count;i++) {
    212 
    213       GLfloat u[3], two_nu;
    214       COPY_2V( u, coord );
    215       u[2] = 0;
    216       NORMALIZE_3FV( u );
    217       two_nu = 2.0F * DOT3(norm,u);
    218       f[0] = u[0] - norm[0] * two_nu;
    219       f[1] = u[1] - norm[1] * two_nu;
    220       f[2] = u[2] - norm[2] * two_nu;
    221 
    222       STRIDE_F(coord,stride);
    223       STRIDE_F(f,fstride);
    224       STRIDE_F(norm, normal->stride);
    225    }
    226 }
    227 
    228 typedef void (*build_f_func)( GLfloat *f,
    229 			      GLuint fstride,
    230 			      const GLvector4f *normal_vec,
    231 			      const GLvector4f *eye );
    232 
    233 
    234 
    235 /* Just treat 4-vectors as 3-vectors.
    236  */
    237 static build_f_func build_f_tab[5] = {
    238    NULL,
    239    NULL,
    240    build_f2,
    241    build_f3,
    242    build_f3
    243 };
    244 
    245 
    246 
    247 /* Special case texgen functions.
    248  */
    249 static void texgen_reflection_map_nv( struct gl_context *ctx,
    250 				      struct texgen_stage_data *store,
    251 				      GLuint unit )
    252 {
    253    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
    254    GLvector4f *in = VB->AttribPtr[VERT_ATTRIB_TEX0 + unit];
    255    GLvector4f *out = &store->texcoord[unit];
    256 
    257    build_f_tab[VB->EyePtr->size]( out->start,
    258 				  out->stride,
    259 				  VB->AttribPtr[_TNL_ATTRIB_NORMAL],
    260 				  VB->EyePtr );
    261 
    262    out->flags |= (in->flags & VEC_SIZE_FLAGS) | VEC_SIZE_3;
    263    out->count = VB->Count;
    264    out->size = MAX2(in->size, 3);
    265    if (in->size == 4)
    266       _mesa_copy_tab[0x8]( out, in );
    267 }
    268 
    269 
    270 
    271 static void texgen_normal_map_nv( struct gl_context *ctx,
    272 				  struct texgen_stage_data *store,
    273 				  GLuint unit )
    274 {
    275    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
    276    GLvector4f *in = VB->AttribPtr[VERT_ATTRIB_TEX0 + unit];
    277    GLvector4f *out = &store->texcoord[unit];
    278    GLvector4f *normal = VB->AttribPtr[_TNL_ATTRIB_NORMAL];
    279    GLfloat (*texcoord)[4] = (GLfloat (*)[4])out->start;
    280    GLuint count = VB->Count;
    281    GLuint i;
    282    const GLfloat *norm = normal->start;
    283 
    284    for (i=0;i<count;i++, STRIDE_F(norm, normal->stride)) {
    285       texcoord[i][0] = norm[0];
    286       texcoord[i][1] = norm[1];
    287       texcoord[i][2] = norm[2];
    288    }
    289 
    290 
    291    out->flags |= (in->flags & VEC_SIZE_FLAGS) | VEC_SIZE_3;
    292    out->count = count;
    293    out->size = MAX2(in->size, 3);
    294    if (in->size == 4)
    295       _mesa_copy_tab[0x8]( out, in );
    296 }
    297 
    298 
    299 static void texgen_sphere_map( struct gl_context *ctx,
    300 			       struct texgen_stage_data *store,
    301 			       GLuint unit )
    302 {
    303    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
    304    GLvector4f *in = VB->AttribPtr[VERT_ATTRIB_TEX0 + unit];
    305    GLvector4f *out = &store->texcoord[unit];
    306    GLfloat (*texcoord)[4] = (GLfloat (*)[4]) out->start;
    307    GLuint count = VB->Count;
    308    GLuint i;
    309    GLfloat (*f)[3] = store->tmp_f;
    310    GLfloat *m = store->tmp_m;
    311 
    312    (build_m_tab[VB->EyePtr->size])( store->tmp_f,
    313 				    store->tmp_m,
    314 				    VB->AttribPtr[_TNL_ATTRIB_NORMAL],
    315 				    VB->EyePtr );
    316 
    317    out->size = MAX2(in->size,2);
    318 
    319    for (i=0;i<count;i++) {
    320       texcoord[i][0] = f[i][0] * m[i] + 0.5F;
    321       texcoord[i][1] = f[i][1] * m[i] + 0.5F;
    322    }
    323 
    324    out->count = count;
    325    out->flags |= (in->flags & VEC_SIZE_FLAGS) | VEC_SIZE_2;
    326    if (in->size > 2)
    327       _mesa_copy_tab[all_bits[in->size] & ~0x3]( out, in );
    328 }
    329 
    330 
    331 
    332 static void texgen( struct gl_context *ctx,
    333 		    struct texgen_stage_data *store,
    334 		    GLuint unit )
    335 {
    336    TNLcontext *tnl = TNL_CONTEXT(ctx);
    337    struct vertex_buffer *VB = &tnl->vb;
    338    GLvector4f *in = VB->AttribPtr[VERT_ATTRIB_TEX0 + unit];
    339    GLvector4f *out = &store->texcoord[unit];
    340    const struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
    341    const GLvector4f *obj = VB->AttribPtr[_TNL_ATTRIB_POS];
    342    const GLvector4f *eye = VB->EyePtr;
    343    const GLvector4f *normal = VB->AttribPtr[_TNL_ATTRIB_NORMAL];
    344    const GLfloat *m = store->tmp_m;
    345    const GLuint count = VB->Count;
    346    GLfloat (*texcoord)[4] = (GLfloat (*)[4])out->data;
    347    GLfloat (*f)[3] = store->tmp_f;
    348    GLuint copy;
    349 
    350    if (texUnit->_GenFlags & TEXGEN_NEED_M) {
    351       build_m_tab[eye->size]( store->tmp_f, store->tmp_m, normal, eye );
    352    } else if (texUnit->_GenFlags & TEXGEN_NEED_F) {
    353       build_f_tab[eye->size]( (GLfloat *)store->tmp_f, 3, normal, eye );
    354    }
    355 
    356 
    357    out->size = MAX2(in->size, store->TexgenSize[unit]);
    358    out->flags |= (in->flags & VEC_SIZE_FLAGS) | texUnit->TexGenEnabled;
    359    out->count = count;
    360 
    361    copy = (all_bits[in->size] & ~texUnit->TexGenEnabled);
    362    if (copy)
    363       _mesa_copy_tab[copy]( out, in );
    364 
    365    if (texUnit->TexGenEnabled & S_BIT) {
    366       GLuint i;
    367       switch (texUnit->GenS.Mode) {
    368       case GL_OBJECT_LINEAR:
    369 	 _mesa_dotprod_tab[obj->size]( (GLfloat *)out->data,
    370 				       sizeof(out->data[0]), obj,
    371 				       texUnit->GenS.ObjectPlane );
    372 	 break;
    373       case GL_EYE_LINEAR:
    374 	 _mesa_dotprod_tab[eye->size]( (GLfloat *)out->data,
    375 				       sizeof(out->data[0]), eye,
    376 				       texUnit->GenS.EyePlane );
    377 	 break;
    378       case GL_SPHERE_MAP:
    379          for (i = 0; i < count; i++)
    380             texcoord[i][0] = f[i][0] * m[i] + 0.5F;
    381 	 break;
    382       case GL_REFLECTION_MAP_NV:
    383 	 for (i=0;i<count;i++)
    384 	     texcoord[i][0] = f[i][0];
    385 	 break;
    386       case GL_NORMAL_MAP_NV: {
    387 	 const GLfloat *norm = normal->start;
    388 	 for (i=0;i<count;i++, STRIDE_F(norm, normal->stride)) {
    389 	     texcoord[i][0] = norm[0];
    390 	 }
    391 	 break;
    392       }
    393       default:
    394 	 _mesa_problem(ctx, "Bad S texgen");
    395       }
    396    }
    397 
    398    if (texUnit->TexGenEnabled & T_BIT) {
    399       GLuint i;
    400       switch (texUnit->GenT.Mode) {
    401       case GL_OBJECT_LINEAR:
    402 	 _mesa_dotprod_tab[obj->size]( &(out->data[0][1]),
    403 				       sizeof(out->data[0]), obj,
    404 				       texUnit->GenT.ObjectPlane );
    405 	 break;
    406       case GL_EYE_LINEAR:
    407 	 _mesa_dotprod_tab[eye->size]( &(out->data[0][1]),
    408 				       sizeof(out->data[0]), eye,
    409 				       texUnit->GenT.EyePlane );
    410 	 break;
    411       case GL_SPHERE_MAP:
    412          for (i = 0; i < count; i++)
    413             texcoord[i][1] = f[i][1] * m[i] + 0.5F;
    414 	 break;
    415       case GL_REFLECTION_MAP_NV:
    416 	 for (i=0;i<count;i++)
    417 	     texcoord[i][1] = f[i][1];
    418 	 break;
    419       case GL_NORMAL_MAP_NV: {
    420 	 const GLfloat *norm = normal->start;
    421 	 for (i=0;i<count;i++, STRIDE_F(norm, normal->stride)) {
    422 	     texcoord[i][1] = norm[1];
    423 	 }
    424 	 break;
    425       }
    426       default:
    427 	 _mesa_problem(ctx, "Bad T texgen");
    428       }
    429    }
    430 
    431    if (texUnit->TexGenEnabled & R_BIT) {
    432       GLuint i;
    433       switch (texUnit->GenR.Mode) {
    434       case GL_OBJECT_LINEAR:
    435 	 _mesa_dotprod_tab[obj->size]( &(out->data[0][2]),
    436 				       sizeof(out->data[0]), obj,
    437 				       texUnit->GenR.ObjectPlane );
    438 	 break;
    439       case GL_EYE_LINEAR:
    440 	 _mesa_dotprod_tab[eye->size]( &(out->data[0][2]),
    441 				       sizeof(out->data[0]), eye,
    442 				       texUnit->GenR.EyePlane );
    443 	 break;
    444       case GL_REFLECTION_MAP_NV:
    445 	 for (i=0;i<count;i++)
    446 	     texcoord[i][2] = f[i][2];
    447 	 break;
    448       case GL_NORMAL_MAP_NV: {
    449 	 const GLfloat *norm = normal->start;
    450 	 for (i=0;i<count;i++,STRIDE_F(norm, normal->stride)) {
    451 	     texcoord[i][2] = norm[2];
    452 	 }
    453 	 break;
    454       }
    455       default:
    456 	 _mesa_problem(ctx, "Bad R texgen");
    457       }
    458    }
    459 
    460    if (texUnit->TexGenEnabled & Q_BIT) {
    461       switch (texUnit->GenQ.Mode) {
    462       case GL_OBJECT_LINEAR:
    463 	 _mesa_dotprod_tab[obj->size]( &(out->data[0][3]),
    464 				       sizeof(out->data[0]), obj,
    465 				       texUnit->GenQ.ObjectPlane );
    466 	 break;
    467       case GL_EYE_LINEAR:
    468 	 _mesa_dotprod_tab[eye->size]( &(out->data[0][3]),
    469 				       sizeof(out->data[0]), eye,
    470 				       texUnit->GenQ.EyePlane );
    471 	 break;
    472       default:
    473 	 _mesa_problem(ctx, "Bad Q texgen");
    474       }
    475    }
    476 }
    477 
    478 
    479 
    480 
    481 static GLboolean run_texgen_stage( struct gl_context *ctx,
    482 				   struct tnl_pipeline_stage *stage )
    483 {
    484    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
    485    struct texgen_stage_data *store = TEXGEN_STAGE_DATA(stage);
    486    GLuint i;
    487 
    488    if (!ctx->Texture._TexGenEnabled || ctx->VertexProgram._Current)
    489       return GL_TRUE;
    490 
    491    for (i = 0 ; i < ctx->Const.MaxTextureCoordUnits ; i++) {
    492       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[i];
    493 
    494       if (texUnit->TexGenEnabled) {
    495 
    496 	 store->TexgenFunc[i]( ctx, store, i );
    497 
    498          VB->AttribPtr[VERT_ATTRIB_TEX0 + i] = &store->texcoord[i];
    499       }
    500    }
    501 
    502    return GL_TRUE;
    503 }
    504 
    505 
    506 static void validate_texgen_stage( struct gl_context *ctx,
    507 				   struct tnl_pipeline_stage *stage )
    508 {
    509    struct texgen_stage_data *store = TEXGEN_STAGE_DATA(stage);
    510    GLuint i;
    511 
    512    if (!ctx->Texture._TexGenEnabled || ctx->VertexProgram._Current)
    513       return;
    514 
    515    for (i = 0 ; i < ctx->Const.MaxTextureCoordUnits ; i++) {
    516       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[i];
    517 
    518       if (texUnit->TexGenEnabled) {
    519 	 GLuint sz;
    520 
    521 	 if (texUnit->TexGenEnabled & Q_BIT)
    522 	    sz = 4;
    523 	 else if (texUnit->TexGenEnabled & R_BIT)
    524 	    sz = 3;
    525 	 else if (texUnit->TexGenEnabled & T_BIT)
    526 	    sz = 2;
    527 	 else
    528 	    sz = 1;
    529 
    530 	 store->TexgenSize[i] = sz;
    531 	 store->TexgenFunc[i] = texgen; /* general solution */
    532 
    533          /* look for special texgen cases */
    534 	 if (texUnit->TexGenEnabled == (S_BIT|T_BIT|R_BIT)) {
    535 	    if (texUnit->_GenFlags == TEXGEN_REFLECTION_MAP_NV) {
    536 	       store->TexgenFunc[i] = texgen_reflection_map_nv;
    537 	    }
    538 	    else if (texUnit->_GenFlags == TEXGEN_NORMAL_MAP_NV) {
    539 	       store->TexgenFunc[i] = texgen_normal_map_nv;
    540 	    }
    541 	 }
    542 	 else if (texUnit->TexGenEnabled == (S_BIT|T_BIT) &&
    543 		  texUnit->_GenFlags == TEXGEN_SPHERE_MAP) {
    544 	    store->TexgenFunc[i] = texgen_sphere_map;
    545 	 }
    546       }
    547    }
    548 }
    549 
    550 
    551 
    552 
    553 
    554 /* Called the first time stage->run() is invoked.
    555  */
    556 static GLboolean alloc_texgen_data( struct gl_context *ctx,
    557 				    struct tnl_pipeline_stage *stage )
    558 {
    559    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
    560    struct texgen_stage_data *store;
    561    GLuint i;
    562 
    563    stage->privatePtr = calloc(1, sizeof(*store));
    564    store = TEXGEN_STAGE_DATA(stage);
    565    if (!store)
    566       return GL_FALSE;
    567 
    568    for (i = 0 ; i < ctx->Const.MaxTextureCoordUnits ; i++)
    569       _mesa_vector4f_alloc( &store->texcoord[i], 0, VB->Size, 32 );
    570 
    571    store->tmp_f = malloc(VB->Size * sizeof(GLfloat) * 3);
    572    store->tmp_m = malloc(VB->Size * sizeof(GLfloat));
    573 
    574    return GL_TRUE;
    575 }
    576 
    577 
    578 static void free_texgen_data( struct tnl_pipeline_stage *stage )
    579 
    580 {
    581    struct texgen_stage_data *store = TEXGEN_STAGE_DATA(stage);
    582    GLuint i;
    583 
    584    if (store) {
    585       for (i = 0 ; i < MAX_TEXTURE_COORD_UNITS ; i++)
    586 	 if (store->texcoord[i].data)
    587 	    _mesa_vector4f_free( &store->texcoord[i] );
    588 
    589 
    590       free( store->tmp_f );
    591       free( store->tmp_m );
    592       free( store );
    593       stage->privatePtr = NULL;
    594    }
    595 }
    596 
    597 
    598 
    599 const struct tnl_pipeline_stage _tnl_texgen_stage =
    600 {
    601    "texgen",			/* name */
    602    NULL,			/* private data */
    603    alloc_texgen_data,		/* destructor */
    604    free_texgen_data,		/* destructor */
    605    validate_texgen_stage,		/* check */
    606    run_texgen_stage		/* run -- initially set to alloc data */
    607 };
    608