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