src/mesa/tnl/t_rasterpos.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   4  *
   5  * Copyright (C) 1999-2007  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  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "main/glheader.h"
  27 #include "main/colormac.h"
  28 #include "main/context.h"
  29 #include "main/feedback.h"
  30 #include "main/light.h"
  31 #include "main/macros.h"
  32 #include "main/rastpos.h"
  33 #include "main/simple_list.h"
  34 #include "main/mtypes.h"
  35
  36 #include "math/m_matrix.h"
  37 #include "tnl/tnl.h"
  38
  39
  40
  41 /**
  42  * Clip a point against the view volume.
  43  *
  44  * \param v vertex vector describing the point to clip.
  45  *
  46  * \return zero if outside view volume, or one if inside.
  47  */
  48 static GLuint
  49 viewclip_point( const GLfloat v[] )
  50 {
  51    if (   v[0] > v[3] || v[0] < -v[3]
  52        || v[1] > v[3] || v[1] < -v[3]
  53        || v[2] > v[3] || v[2] < -v[3] ) {
  54       return 0;
  55    }
  56    else {
  57       return 1;
  58    }
  59 }
  60
  61
  62 /**
  63  * Clip a point against the far/near Z clipping planes.
  64  *
  65  * \param v vertex vector describing the point to clip.
  66  *
  67  * \return zero if outside view volume, or one if inside.
  68  */
  69 static GLuint
  70 viewclip_point_z( const GLfloat v[] )
  71 {
  72    if (v[2] > v[3] || v[2] < -v[3] ) {
  73       return 0;
  74    }
  75    else {
  76       return 1;
  77    }
  78 }
  79
  80
  81 /**
  82  * Clip a point against the user clipping planes.
  83  *
  84  * \param ctx GL context.
  85  * \param v vertex vector describing the point to clip.
  86  *
  87  * \return zero if the point was clipped, or one otherwise.
  88  */
  89 static GLuint
  90 userclip_point( GLcontext *ctx, const GLfloat v[] )
  91 {
  92    GLuint p;
  93
  94    for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
  95       if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
  96          GLfloat dot = v[0] * ctx->Transform._ClipUserPlane[p][0]
  97                      + v[1] * ctx->Transform._ClipUserPlane[p][1]
  98                      + v[2] * ctx->Transform._ClipUserPlane[p][2]
  99                      + v[3] * ctx->Transform._ClipUserPlane[p][3];
 100          if (dot < 0.0F) {
 101             return 0;
 102          }
 103       }
 104    }
 105
 106    return 1;
 107 }
 108
 109
 110 /**
 111  * Compute lighting for the raster position.  Both RGB and CI modes computed.
 112  * \param ctx the context
 113  * \param vertex vertex location
 114  * \param normal normal vector
 115  * \param Rcolor returned color
 116  * \param Rspec returned specular color (if separate specular enabled)
 117  * \param Rindex returned color index
 118  */
 119 static void
 120 shade_rastpos(GLcontext *ctx,
 121               const GLfloat vertex[4],
 122               const GLfloat normal[3],
 123               GLfloat Rcolor[4],
 124               GLfloat Rspec[4],
 125               GLfloat *Rindex)
 126 {
 127    /*const*/ GLfloat (*base)[3] = ctx->Light._BaseColor;
 128    const struct gl_light *light;
 129    GLfloat diffuseColor[4], specularColor[4];  /* for RGB mode only */
 130    GLfloat diffuseCI = 0.0, specularCI = 0.0;  /* for CI mode only */
 131
 132    _mesa_validate_all_lighting_tables( ctx );
 133
 134    COPY_3V(diffuseColor, base[0]);
 135    diffuseColor[3] = CLAMP(
 136       ctx->Light.Material.Attrib[MAT_ATTRIB_FRONT_DIFFUSE][3], 0.0F, 1.0F );
 137    ASSIGN_4V(specularColor, 0.0, 0.0, 0.0, 1.0);
 138
 139    foreach (light, &ctx->Light.EnabledList) {
 140       GLfloat attenuation = 1.0;
 141       GLfloat VP[3]; /* vector from vertex to light pos */
 142       GLfloat n_dot_VP;
 143       GLfloat diffuseContrib[3], specularContrib[3];
 144
 145       if (!(light->_Flags & LIGHT_POSITIONAL)) {
 146          /* light at infinity */
 147          COPY_3V(VP, light->_VP_inf_norm);
 148          attenuation = light->_VP_inf_spot_attenuation;
 149       }
 150       else {
 151          /* local/positional light */
 152          GLfloat d;
 153
 154          /* VP = vector from vertex pos to light[i].pos */
 155          SUB_3V(VP, light->_Position, vertex);
 156          /* d = length(VP) */
 157          d = (GLfloat) LEN_3FV( VP );
 158          if (d > 1.0e-6) {
 159             /* normalize VP */
 160             GLfloat invd = 1.0F / d;
 161             SELF_SCALE_SCALAR_3V(VP, invd);
 162          }
 163
 164          /* atti */
 165          attenuation = 1.0F / (light->ConstantAttenuation + d *
 166                                (light->LinearAttenuation + d *
 167                                 light->QuadraticAttenuation));
 168
 169          if (light->_Flags & LIGHT_SPOT) {
 170             GLfloat PV_dot_dir = - DOT3(VP, light->_NormDirection);
 171
 172             if (PV_dot_dir<light->_CosCutoff) {
 173                continue;
 174             }
 175             else {
 176                double x = PV_dot_dir * (EXP_TABLE_SIZE-1);
 177                int k = (int) x;
 178                GLfloat spot = (GLfloat) (light->_SpotExpTable[k][0]
 179                                + (x-k)*light->_SpotExpTable[k][1]);
 180                attenuation *= spot;
 181             }
 182          }
 183       }
 184
 185       if (attenuation < 1e-3)
 186          continue;
 187
 188       n_dot_VP = DOT3( normal, VP );
 189
 190       if (n_dot_VP < 0.0F) {
 191          ACC_SCALE_SCALAR_3V(diffuseColor, attenuation, light->_MatAmbient[0]);
 192          continue;
 193       }
 194
 195       /* Ambient + diffuse */
 196       COPY_3V(diffuseContrib, light->_MatAmbient[0]);
 197       ACC_SCALE_SCALAR_3V(diffuseContrib, n_dot_VP, light->_MatDiffuse[0]);
 198       diffuseCI += n_dot_VP * light->_dli * attenuation;
 199
 200       /* Specular */
 201       {
 202          const GLfloat *h;
 203          GLfloat n_dot_h;
 204
 205          ASSIGN_3V(specularContrib, 0.0, 0.0, 0.0);
 206
 207          if (ctx->Light.Model.LocalViewer) {
 208             GLfloat v[3];
 209             COPY_3V(v, vertex);
 210             NORMALIZE_3FV(v);
 211             SUB_3V(VP, VP, v);
 212             NORMALIZE_3FV(VP);
 213             h = VP;
 214          }
 215          else if (light->_Flags & LIGHT_POSITIONAL) {
 216             ACC_3V(VP, ctx->_EyeZDir);
 217             NORMALIZE_3FV(VP);
 218             h = VP;
 219          }
 220          else {
 221             h = light->_h_inf_norm;
 222          }
 223
 224          n_dot_h = DOT3(normal, h);
 225
 226          if (n_dot_h > 0.0F) {
 227             GLfloat spec_coef;
 228             GET_SHINE_TAB_ENTRY( ctx->_ShineTable[0], n_dot_h, spec_coef );
 229
 230             if (spec_coef > 1.0e-10) {
 231                if (ctx->Light.Model.ColorControl==GL_SEPARATE_SPECULAR_COLOR) {
 232                   ACC_SCALE_SCALAR_3V( specularContrib, spec_coef,
 233                                        light->_MatSpecular[0]);
 234                }
 235                else {
 236                   ACC_SCALE_SCALAR_3V( diffuseContrib, spec_coef,
 237                                        light->_MatSpecular[0]);
 238                }
 239                /*assert(light->_sli > 0.0);*/
 240                specularCI += spec_coef * light->_sli * attenuation;
 241             }
 242          }
 243       }
 244
 245       ACC_SCALE_SCALAR_3V( diffuseColor, attenuation, diffuseContrib );
 246       ACC_SCALE_SCALAR_3V( specularColor, attenuation, specularContrib );
 247    }
 248
 249    if (ctx->Visual.rgbMode) {
 250       Rcolor[0] = CLAMP(diffuseColor[0], 0.0F, 1.0F);
 251       Rcolor[1] = CLAMP(diffuseColor[1], 0.0F, 1.0F);
 252       Rcolor[2] = CLAMP(diffuseColor[2], 0.0F, 1.0F);
 253       Rcolor[3] = CLAMP(diffuseColor[3], 0.0F, 1.0F);
 254       Rspec[0] = CLAMP(specularColor[0], 0.0F, 1.0F);
 255       Rspec[1] = CLAMP(specularColor[1], 0.0F, 1.0F);
 256       Rspec[2] = CLAMP(specularColor[2], 0.0F, 1.0F);
 257       Rspec[3] = CLAMP(specularColor[3], 0.0F, 1.0F);
 258    }
 259    else {
 260       GLfloat *ind = ctx->Light.Material.Attrib[MAT_ATTRIB_FRONT_INDEXES];
 261       GLfloat d_a = ind[MAT_INDEX_DIFFUSE] - ind[MAT_INDEX_AMBIENT];
 262       GLfloat s_a = ind[MAT_INDEX_SPECULAR] - ind[MAT_INDEX_AMBIENT];
 263       GLfloat i = (ind[MAT_INDEX_AMBIENT]
 264                    + diffuseCI * (1.0F-specularCI) * d_a
 265                    + specularCI * s_a);
 266       if (i > ind[MAT_INDEX_SPECULAR]) {
 267          i = ind[MAT_INDEX_SPECULAR];
 268       }
 269       *Rindex = i;
 270    }
 271 }
 272
 273
 274 /**
 275  * Do texgen needed for glRasterPos.
 276  * \param ctx  rendering context
 277  * \param vObj  object-space vertex coordinate
 278  * \param vEye  eye-space vertex coordinate
 279  * \param normal  vertex normal
 280  * \param unit  texture unit number
 281  * \param texcoord  incoming texcoord and resulting texcoord
 282  */
 283 static void
 284 compute_texgen(GLcontext *ctx, const GLfloat vObj[4], const GLfloat vEye[4],
 285                const GLfloat normal[3], GLuint unit, GLfloat texcoord[4])
 286 {
 287    const struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
 288
 289    /* always compute sphere map terms, just in case */
 290    GLfloat u[3], two_nu, rx, ry, rz, m, mInv;
 291    COPY_3V(u, vEye);
 292    NORMALIZE_3FV(u);
 293    two_nu = 2.0F * DOT3(normal, u);
 294    rx = u[0] - normal[0] * two_nu;
 295    ry = u[1] - normal[1] * two_nu;
 296    rz = u[2] - normal[2] * two_nu;
 297    m = rx * rx + ry * ry + (rz + 1.0F) * (rz + 1.0F);
 298    if (m > 0.0F)
 299       mInv = 0.5F * _mesa_inv_sqrtf(m);
 300    else
 301       mInv = 0.0F;
 302
 303    if (texUnit->TexGenEnabled & S_BIT) {
 304       switch (texUnit->GenModeS) {
 305          case GL_OBJECT_LINEAR:
 306             texcoord[0] = DOT4(vObj, texUnit->ObjectPlaneS);
 307             break;
 308          case GL_EYE_LINEAR:
 309             texcoord[0] = DOT4(vEye, texUnit->EyePlaneS);
 310             break;
 311          case GL_SPHERE_MAP:
 312             texcoord[0] = rx * mInv + 0.5F;
 313             break;
 314          case GL_REFLECTION_MAP:
 315             texcoord[0] = rx;
 316             break;
 317          case GL_NORMAL_MAP:
 318             texcoord[0] = normal[0];
 319             break;
 320          default:
 321             _mesa_problem(ctx, "Bad S texgen in compute_texgen()");
 322             return;
 323       }
 324    }
 325
 326    if (texUnit->TexGenEnabled & T_BIT) {
 327       switch (texUnit->GenModeT) {
 328          case GL_OBJECT_LINEAR:
 329             texcoord[1] = DOT4(vObj, texUnit->ObjectPlaneT);
 330             break;
 331          case GL_EYE_LINEAR:
 332             texcoord[1] = DOT4(vEye, texUnit->EyePlaneT);
 333             break;
 334          case GL_SPHERE_MAP:
 335             texcoord[1] = ry * mInv + 0.5F;
 336             break;
 337          case GL_REFLECTION_MAP:
 338             texcoord[1] = ry;
 339             break;
 340          case GL_NORMAL_MAP:
 341             texcoord[1] = normal[1];
 342             break;
 343          default:
 344             _mesa_problem(ctx, "Bad T texgen in compute_texgen()");
 345             return;
 346       }
 347    }
 348
 349    if (texUnit->TexGenEnabled & R_BIT) {
 350       switch (texUnit->GenModeR) {
 351          case GL_OBJECT_LINEAR:
 352             texcoord[2] = DOT4(vObj, texUnit->ObjectPlaneR);
 353             break;
 354          case GL_EYE_LINEAR:
 355             texcoord[2] = DOT4(vEye, texUnit->EyePlaneR);
 356             break;
 357          case GL_REFLECTION_MAP:
 358             texcoord[2] = rz;
 359             break;
 360          case GL_NORMAL_MAP:
 361             texcoord[2] = normal[2];
 362             break;
 363          default:
 364             _mesa_problem(ctx, "Bad R texgen in compute_texgen()");
 365             return;
 366       }
 367    }
 368
 369    if (texUnit->TexGenEnabled & Q_BIT) {
 370       switch (texUnit->GenModeQ) {
 371          case GL_OBJECT_LINEAR:
 372             texcoord[3] = DOT4(vObj, texUnit->ObjectPlaneQ);
 373             break;
 374          case GL_EYE_LINEAR:
 375             texcoord[3] = DOT4(vEye, texUnit->EyePlaneQ);
 376             break;
 377          default:
 378             _mesa_problem(ctx, "Bad Q texgen in compute_texgen()");
 379             return;
 380       }
 381    }
 382 }
 383
 384
 385 /**
 386  * glRasterPos transformation.  Typically called via ctx->Driver.RasterPos().
 387  * XXX some of this code (such as viewport xform, clip testing and setting
 388  * of ctx->Current.Raster* fields) could get lifted up into the
 389  * main/rasterpos.c code.
 390  *
 391  * \param vObj  vertex position in object space
 392  */
 393 void
 394 _tnl_RasterPos(GLcontext *ctx, const GLfloat vObj[4])
 395 {
 396    if (ctx->VertexProgram._Enabled) {
 397       /* XXX implement this */
 398       _mesa_problem(ctx, "Vertex programs not implemented for glRasterPos");
 399       return;
 400    }
 401    else {
 402       GLfloat eye[4], clip[4], ndc[3], d;
 403       GLfloat *norm, eyenorm[3];
 404       GLfloat *objnorm = ctx->Current.Attrib[VERT_ATTRIB_NORMAL];
 405
 406       /* apply modelview matrix:  eye = MV * obj */
 407       TRANSFORM_POINT( eye, ctx->ModelviewMatrixStack.Top->m, vObj );
 408       /* apply projection matrix:  clip = Proj * eye */
 409       TRANSFORM_POINT( clip, ctx->ProjectionMatrixStack.Top->m, eye );
 410
 411       /* clip to view volume */
 412       if (ctx->Transform.RasterPositionUnclipped) {
 413          /* GL_IBM_rasterpos_clip: only clip against Z */
 414          if (viewclip_point_z(clip) == 0) {
 415             ctx->Current.RasterPosValid = GL_FALSE;
 416             return;
 417          }
 418       }
 419       else if (viewclip_point(clip) == 0) {
 420          /* Normal OpenGL behaviour */
 421          ctx->Current.RasterPosValid = GL_FALSE;
 422          return;
 423       }
 424
 425       /* clip to user clipping planes */
 426       if (ctx->Transform.ClipPlanesEnabled && !userclip_point(ctx, clip)) {
 427          ctx->Current.RasterPosValid = GL_FALSE;
 428          return;
 429       }
 430
 431       /* ndc = clip / W */
 432       d = (clip[3] == 0.0F) ? 1.0F : 1.0F / clip[3];
 433       ndc[0] = clip[0] * d;
 434       ndc[1] = clip[1] * d;
 435       ndc[2] = clip[2] * d;
 436       /* wincoord = viewport_mapping(ndc) */
 437       ctx->Current.RasterPos[0] = (ndc[0] * ctx->Viewport._WindowMap.m[MAT_SX]
 438                                    + ctx->Viewport._WindowMap.m[MAT_TX]);
 439       ctx->Current.RasterPos[1] = (ndc[1] * ctx->Viewport._WindowMap.m[MAT_SY]
 440                                    + ctx->Viewport._WindowMap.m[MAT_TY]);
 441       ctx->Current.RasterPos[2] = (ndc[2] * ctx->Viewport._WindowMap.m[MAT_SZ]
 442                                    + ctx->Viewport._WindowMap.m[MAT_TZ])
 443                                   / ctx->DrawBuffer->_DepthMaxF;
 444       ctx->Current.RasterPos[3] = clip[3];
 445
 446       /* compute raster distance */
 447       if (ctx->Fog.FogCoordinateSource == GL_FOG_COORDINATE_EXT)
 448          ctx->Current.RasterDistance = ctx->Current.Attrib[VERT_ATTRIB_FOG][0];
 449       else
 450          ctx->Current.RasterDistance =
 451                         SQRTF( eye[0]*eye[0] + eye[1]*eye[1] + eye[2]*eye[2] );
 452
 453       /* compute transformed normal vector (for lighting or texgen) */
 454       if (ctx->_NeedEyeCoords) {
 455          const GLfloat *inv = ctx->ModelviewMatrixStack.Top->inv;
 456          TRANSFORM_NORMAL( eyenorm, objnorm, inv );
 457          norm = eyenorm;
 458       }
 459       else {
 460          norm = objnorm;
 461       }
 462
 463       /* update raster color */
 464       if (ctx->Light.Enabled) {
 465          /* lighting */
 466          shade_rastpos( ctx, vObj, norm,
 467                         ctx->Current.RasterColor,
 468                         ctx->Current.RasterSecondaryColor,
 469                         &ctx->Current.RasterIndex );
 470       }
 471       else {
 472          /* use current color or index */
 473          if (ctx->Visual.rgbMode) {
 474             COPY_4FV(ctx->Current.RasterColor,
 475                      ctx->Current.Attrib[VERT_ATTRIB_COLOR0]);
 476             COPY_4FV(ctx->Current.RasterSecondaryColor,
 477                      ctx->Current.Attrib[VERT_ATTRIB_COLOR1]);
 478          }
 479          else {
 480             ctx->Current.RasterIndex
 481                = ctx->Current.Attrib[VERT_ATTRIB_COLOR_INDEX][0];
 482          }
 483       }
 484
 485       /* texture coords */
 486       {
 487          GLuint u;
 488          for (u = 0; u < ctx->Const.MaxTextureCoordUnits; u++) {
 489             GLfloat tc[4];
 490             COPY_4V(tc, ctx->Current.Attrib[VERT_ATTRIB_TEX0 + u]);
 491             if (ctx->Texture.Unit[u].TexGenEnabled) {
 492                compute_texgen(ctx, vObj, eye, norm, u, tc);
 493             }
 494             TRANSFORM_POINT(ctx->Current.RasterTexCoords[u],
 495                             ctx->TextureMatrixStack[u].Top->m, tc);
 496          }
 497       }
 498
 499       ctx->Current.RasterPosValid = GL_TRUE;
 500    }
 501
 502    if (ctx->RenderMode == GL_SELECT) {
 503       _mesa_update_hitflag( ctx, ctx->Current.RasterPos[2] );
 504    }
 505 }