src/mesa/main/clip.c

   1 /* $Id: clip.c,v 1.5 1999/11/11 01:22:25 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.3
   6  *
   7  * Copyright (C) 1999  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27
  28 #ifdef PC_HEADER
  29 #include "all.h"
  30 #else
  31 #include "glheader.h"
  32 #include "clip.h"
  33 #include "context.h"
  34 #include "macros.h"
  35 #include "matrix.h"
  36 #include "mmath.h"
  37 #include "types.h"
  38 #include "vb.h"
  39 #include "xform.h"
  40 #endif
  41
  42
  43
  44
  45 /* Linear interpolation between A and B: */
  46 #define LINTERP( T, A, B )   ( (A) + (T) * ( (B) - (A) ) )
  47
  48
  49
  50 #define INTERP_SZ( t, vec, to, a, b, sz )                       \
  51 do {                                                            \
  52    switch (sz) {                                                \
  53    case 4: vec[to][3] = LINTERP( t, vec[a][3], vec[b][3] );     \
  54    case 3: vec[to][2] = LINTERP( t, vec[a][2], vec[b][2] );     \
  55    case 2: vec[to][1] = LINTERP( t, vec[a][1], vec[b][1] );     \
  56    case 1: vec[to][0] = LINTERP( t, vec[a][0], vec[b][0] );     \
  57    }                                                            \
  58 } while(0)
  59
  60
  61
  62
  63 #define CLIP_RGBA0    0x1
  64 #define CLIP_RGBA1    0x2
  65 #define CLIP_TEX0     0x4
  66 #define CLIP_TEX1     0x8
  67 #define CLIP_INDEX0   0x10
  68 #define CLIP_INDEX1   0x20
  69
  70 static clip_interp_func clip_interp_tab[0x40];
  71
  72 #define IND 0
  73 #define NAME clip_nil
  74 #include "interp_tmp.h"
  75
  76 #define IND (CLIP_RGBA0)
  77 #define NAME clipRGBA0
  78 #include "interp_tmp.h"
  79
  80 #define IND (CLIP_RGBA0|CLIP_RGBA1)
  81 #define NAME clipRGBA0_RGBA1
  82 #include "interp_tmp.h"
  83
  84 #define IND (CLIP_TEX0|CLIP_RGBA0)
  85 #define NAME clipTEX0_RGBA0
  86 #include "interp_tmp.h"
  87
  88 #define IND (CLIP_TEX0|CLIP_RGBA0|CLIP_RGBA1)
  89 #define NAME clipTEX0_RGBA0_RGBA1
  90 #include "interp_tmp.h"
  91
  92 #define IND (CLIP_TEX1|CLIP_TEX0|CLIP_RGBA0)
  93 #define NAME clipTEX1_TEX0_RGBA0
  94 #include "interp_tmp.h"
  95
  96 #define IND (CLIP_TEX0)
  97 #define NAME clipTEX0
  98 #include "interp_tmp.h"
  99
 100 #define IND (CLIP_TEX1|CLIP_TEX0)
 101 #define NAME clipTEX1_TEX0
 102 #include "interp_tmp.h"
 103
 104 #define IND (CLIP_TEX1|CLIP_TEX0|CLIP_RGBA0|CLIP_RGBA1)
 105 #define NAME clipTEX1_TEX0_RGBA0_RGBA1
 106 #include "interp_tmp.h"
 107
 108 #define IND (CLIP_INDEX0)
 109 #define NAME clipINDEX0
 110 #include "interp_tmp.h"
 111
 112 #define IND (CLIP_INDEX0|CLIP_INDEX1)
 113 #define NAME clipINDEX0_INDEX1
 114 #include "interp_tmp.h"
 115
 116
 117
 118
 119 /**********************************************************************/
 120 /*                     Get/Set User clip-planes.                      */
 121 /**********************************************************************/
 122
 123
 124
 125 void
 126 _mesa_ClipPlane( GLenum plane, const GLdouble *eq )
 127 {
 128    GET_CURRENT_CONTEXT(ctx);
 129    GLint p;
 130    GLfloat equation[4];
 131
 132    equation[0] = eq[0];
 133    equation[1] = eq[1];
 134    equation[2] = eq[2];
 135    equation[3] = eq[3];
 136
 137    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glClipPlane");
 138
 139    p = (GLint) plane - (GLint) GL_CLIP_PLANE0;
 140    if (p<0 || p>=MAX_CLIP_PLANES) {
 141       gl_error( ctx, GL_INVALID_ENUM, "glClipPlane" );
 142       return;
 143    }
 144
 145    /*
 146     * The equation is transformed by the transpose of the inverse of the
 147     * current modelview matrix and stored in the resulting eye coordinates.
 148     *
 149     * KW: Eqn is then transformed to the current clip space, where user
 150     * clipping now takes place.  The clip-space equations are recalculated
 151     * whenever the projection matrix changes.
 152     */
 153    if (ctx->ModelView.flags & MAT_DIRTY_ALL_OVER) {
 154       gl_matrix_analyze( &ctx->ModelView );
 155    }
 156    gl_transform_vector( ctx->Transform.EyeUserPlane[p], equation,
 157                         ctx->ModelView.inv );
 158
 159
 160    if (ctx->Transform.ClipEnabled[p]) {
 161       ctx->NewState |= NEW_USER_CLIP;
 162
 163       if (ctx->ProjectionMatrix.flags & MAT_DIRTY_ALL_OVER) {
 164          gl_matrix_analyze( &ctx->ProjectionMatrix );
 165       }
 166       gl_transform_vector( ctx->Transform.ClipUserPlane[p],
 167                            ctx->Transform.EyeUserPlane[p],
 168                            ctx->ProjectionMatrix.inv );
 169    }
 170 }
 171
 172
 173 void gl_update_userclip( GLcontext *ctx )
 174 {
 175    GLuint p;
 176
 177    for (p = 0 ; p < MAX_CLIP_PLANES ; p++) {
 178       if (ctx->Transform.ClipEnabled[p]) {
 179          gl_transform_vector( ctx->Transform.ClipUserPlane[p],
 180                               ctx->Transform.EyeUserPlane[p],
 181                               ctx->ProjectionMatrix.inv );
 182       }
 183    }
 184 }
 185
 186 void
 187 _mesa_GetClipPlane( GLenum plane, GLdouble *equation )
 188 {
 189    GET_CURRENT_CONTEXT(ctx);
 190    GLint p;
 191
 192    ASSERT_OUTSIDE_BEGIN_END(ctx, "glGetClipPlane");
 193
 194
 195    p = (GLint) (plane - GL_CLIP_PLANE0);
 196    if (p<0 || p>=MAX_CLIP_PLANES) {
 197       gl_error( ctx, GL_INVALID_ENUM, "glGetClipPlane" );
 198       return;
 199    }
 200
 201    equation[0] = (GLdouble) ctx->Transform.EyeUserPlane[p][0];
 202    equation[1] = (GLdouble) ctx->Transform.EyeUserPlane[p][1];
 203    equation[2] = (GLdouble) ctx->Transform.EyeUserPlane[p][2];
 204    equation[3] = (GLdouble) ctx->Transform.EyeUserPlane[p][3];
 205 }
 206
 207
 208
 209
 210 /**********************************************************************/
 211 /*                         View volume clipping.                      */
 212 /**********************************************************************/
 213
 214
 215 /*
 216  * Clip a point against the view volume.
 217  * Input:  v - vertex-vector describing the point to clip
 218  * Return:  0 = outside view volume
 219  *          1 = inside view volume
 220  */
 221 GLuint gl_viewclip_point( const GLfloat v[] )
 222 {
 223    if (   v[0] > v[3] || v[0] < -v[3]
 224        || v[1] > v[3] || v[1] < -v[3]
 225        || v[2] > v[3] || v[2] < -v[3] ) {
 226       return 0;
 227    }
 228    else {
 229       return 1;
 230    }
 231 }
 232
 233 /*
 234  * Clip a point against the user clipping planes.
 235  * Input:  v - vertex-vector describing the point to clip.
 236  * Return:  0 = point was clipped
 237  *          1 = point not clipped
 238  */
 239 GLuint gl_userclip_point( GLcontext* ctx, const GLfloat v[] )
 240 {
 241    GLuint p;
 242
 243    for (p=0;p<MAX_CLIP_PLANES;p++) {
 244       if (ctx->Transform.ClipEnabled[p]) {
 245          GLfloat dot = v[0] * ctx->Transform.ClipUserPlane[p][0]
 246                      + v[1] * ctx->Transform.ClipUserPlane[p][1]
 247                      + v[2] * ctx->Transform.ClipUserPlane[p][2]
 248                      + v[3] * ctx->Transform.ClipUserPlane[p][3];
 249          if (dot < 0.0F) {
 250             return 0;
 251          }
 252       }
 253    }
 254
 255    return 1;
 256 }
 257
 258
 259
 260
 261 #if defined(__i386__)
 262 #define NEGATIVE(x) ((*(int *)&x)<0)
 263 #else
 264 #define NEGATIVE(x) (x < 0)
 265 #endif
 266
 267
 268 static clip_poly_func gl_poly_clip_tab[2][5];
 269 static clip_line_func gl_line_clip_tab[2][5];
 270
 271 #define W(i) coord[i][3]
 272 #define Z(i) coord[i][2]
 273 #define Y(i) coord[i][1]
 274 #define X(i) coord[i][0]
 275 #define SIZE 4
 276 #define IND 0
 277 #define TAG(x) x##_4
 278 #include "clip_funcs.h"
 279
 280 #define W(i) 1.0
 281 #define Z(i) coord[i][2]
 282 #define Y(i) coord[i][1]
 283 #define X(i) coord[i][0]
 284 #define SIZE 3
 285 #define IND 0
 286 #define TAG(x) x##_3
 287 #include "clip_funcs.h"
 288
 289 #define W(i) 1.0
 290 #define Z(i) 0.0
 291 #define Y(i) coord[i][1]
 292 #define X(i) coord[i][0]
 293 #define SIZE 2
 294 #define IND 0
 295 #define TAG(x) x##_2
 296 #include "clip_funcs.h"
 297
 298 #define W(i) coord[i][3]
 299 #define Z(i) coord[i][2]
 300 #define Y(i) coord[i][1]
 301 #define X(i) coord[i][0]
 302 #define SIZE 4
 303 #define IND CLIP_TAB_EDGEFLAG
 304 #define TAG(x) x##_4_edgeflag
 305 #include "clip_funcs.h"
 306
 307 #define W(i) 1.0
 308 #define Z(i) coord[i][2]
 309 #define Y(i) coord[i][1]
 310 #define X(i) coord[i][0]
 311 #define SIZE 3
 312 #define IND CLIP_TAB_EDGEFLAG
 313 #define TAG(x) x##_3_edgeflag
 314 #include "clip_funcs.h"
 315
 316 #define W(i) 1.0
 317 #define Z(i) 0.0
 318 #define Y(i) coord[i][1]
 319 #define X(i) coord[i][0]
 320 #define SIZE 2
 321 #define IND CLIP_TAB_EDGEFLAG
 322 #define TAG(x) x##_2_edgeflag
 323 #include "clip_funcs.h"
 324
 325
 326
 327
 328 void gl_update_clipmask( GLcontext *ctx )
 329 {
 330    GLuint mask = 0;
 331
 332    if (ctx->Visual->RGBAflag)
 333    {
 334       if (ctx->Light.ShadeModel==GL_SMOOTH)
 335       {
 336          mask |= CLIP_RGBA0;
 337
 338          if (ctx->TriangleCaps & (DD_TRI_LIGHT_TWOSIDE|DD_SEPERATE_SPECULAR))
 339             mask |= CLIP_RGBA1;
 340       }
 341
 342       if (ctx->Texture.ReallyEnabled & 0xf0)
 343          mask |= CLIP_TEX1|CLIP_TEX0;
 344
 345       if (ctx->Texture.ReallyEnabled & 0xf)
 346          mask |= CLIP_TEX0;
 347    }
 348    else if (ctx->Light.ShadeModel==GL_SMOOTH)
 349    {
 350       mask |= CLIP_INDEX0;
 351
 352       if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE)
 353          mask |= CLIP_INDEX1;
 354    }
 355
 356
 357    ctx->ClipInterpFunc = clip_interp_tab[mask];
 358    ctx->poly_clip_tab = gl_poly_clip_tab[0];
 359    ctx->line_clip_tab = gl_line_clip_tab[0];
 360
 361    if (ctx->TriangleCaps & DD_TRI_UNFILLED) {
 362       ctx->poly_clip_tab = gl_poly_clip_tab[1];
 363       ctx->line_clip_tab = gl_line_clip_tab[0];
 364    }
 365 }
 366
 367
 368 #define USER_CLIPTEST(NAME, SZ)                                         \
 369 static void NAME( struct vertex_buffer *VB )                            \
 370 {                                                                       \
 371    GLcontext *ctx = VB->ctx;                                            \
 372    GLubyte *clipMask = VB->ClipMask;                                    \
 373    GLubyte *userClipMask = VB->UserClipMask;                            \
 374    GLuint start = VB->Start;                                            \
 375    GLuint count = VB->Count;                                            \
 376    GLuint p, i;                                                         \
 377    GLubyte bit;                                                         \
 378                                                                         \
 379                                                                         \
 380    for (bit = 1, p = 0; p < MAX_CLIP_PLANES ; p++, bit *=2)             \
 381       if (ctx->Transform.ClipEnabled[p]) {                              \
 382          GLuint nr = 0;                                                 \
 383          const GLfloat a = ctx->Transform.ClipUserPlane[p][0];          \
 384          const GLfloat b = ctx->Transform.ClipUserPlane[p][1];          \
 385          const GLfloat c = ctx->Transform.ClipUserPlane[p][2];          \
 386          const GLfloat d = ctx->Transform.ClipUserPlane[p][3];          \
 387          GLfloat *coord = VB->ClipPtr->start;                           \
 388          GLuint stride = VB->ClipPtr->stride;                           \
 389                                                                         \
 390          for (i = start ; i < count ; i++, STRIDE_F(coord, stride)) {   \
 391             GLfloat dp = coord[0] * a + coord[1] * b;                   \
 392             if (SZ > 2) dp += coord[2] * c;                             \
 393             if (SZ > 3) dp += coord[3] * d; else dp += d;               \
 394                                                                         \
 395             if (dp < 0) {                                               \
 396                clipMask[i] |= CLIP_USER_BIT;                            \
 397                userClipMask[i] |= bit;                                  \
 398                nr++;                                                    \
 399             }                                                           \
 400          }                                                              \
 401                                                                         \
 402          if (nr > 0) {                                                  \
 403             VB->ClipOrMask |= CLIP_USER_BIT;                            \
 404             VB->CullMode |= CLIP_MASK_ACTIVE;                           \
 405             if (nr == count - start) {                                  \
 406                VB->ClipAndMask |= CLIP_USER_BIT;                        \
 407                VB->Culled = 1;                                          \
 408                return;                                                  \
 409             }                                                           \
 410          }                                                              \
 411       }                                                                 \
 412 }
 413
 414
 415 USER_CLIPTEST(userclip2, 2)
 416 USER_CLIPTEST(userclip3, 3)
 417 USER_CLIPTEST(userclip4, 4)
 418
 419 static void (*(usercliptab[5]))( struct vertex_buffer * ) = {
 420    0,
 421    0,
 422    userclip2,
 423    userclip3,
 424    userclip4
 425 };
 426
 427 void gl_user_cliptest( struct vertex_buffer *VB )
 428 {
 429    usercliptab[VB->ClipPtr->size]( VB );
 430 }
 431
 432
 433 void gl_init_clip(void)
 434 {
 435    init_clip_funcs_4();
 436    init_clip_funcs_3();
 437    init_clip_funcs_2();
 438
 439    init_clip_funcs_4_edgeflag();
 440    init_clip_funcs_3_edgeflag();
 441    init_clip_funcs_2_edgeflag();
 442
 443    clip_interp_tab[0] = clip_nil;
 444    clip_interp_tab[CLIP_RGBA0] = clipRGBA0;
 445    clip_interp_tab[CLIP_RGBA0|CLIP_RGBA1] = clipRGBA0_RGBA1;
 446    clip_interp_tab[CLIP_TEX0|CLIP_RGBA0] = clipTEX0_RGBA0;
 447    clip_interp_tab[CLIP_TEX0|CLIP_RGBA0|CLIP_RGBA1] = clipTEX0_RGBA0_RGBA1;
 448    clip_interp_tab[CLIP_TEX1|CLIP_TEX0|CLIP_RGBA0] = clipTEX1_TEX0_RGBA0;
 449    clip_interp_tab[CLIP_TEX1|CLIP_TEX0|CLIP_RGBA0|CLIP_RGBA1] =
 450       clipTEX1_TEX0_RGBA0_RGBA1;
 451
 452    clip_interp_tab[CLIP_TEX0] = clipTEX0;
 453    clip_interp_tab[CLIP_TEX1|CLIP_TEX0] = clipTEX1_TEX0;
 454
 455    clip_interp_tab[CLIP_INDEX0] = clipINDEX0;
 456    clip_interp_tab[CLIP_INDEX0|CLIP_INDEX1] = clipINDEX0_INDEX1;
 457 }
 458