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