src/mesa/tnl/t_vb_cliptmp.h

   1 /* $Id: t_vb_cliptmp.h,v 1.14 2001/07/13 17:26:39 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.5
   6  *
   7  * Copyright (C) 1999-2001  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  * Authors:
  27  *    Keith Whitwell <keithw@valinux.com>
  28  */
  29
  30
  31 #define CLIP_DOTPROD(K, A, B, C, D) X(K)*A + Y(K)*B + Z(K)*C + W(K)*D
  32
  33 #define POLY_CLIP( PLANE, A, B, C, D )                                  \
  34 do {                                                                    \
  35    if (mask & PLANE) {                                                  \
  36       GLuint idxPrev = inlist[0];                                       \
  37       GLfloat dpPrev = CLIP_DOTPROD(idxPrev, A, B, C, D );              \
  38       GLuint outcount = 0;                                              \
  39       GLuint i;                                                         \
  40                                                                         \
  41       inlist[n] = inlist[0]; /* prevent rotation of vertices */         \
  42       for (i = 1; i <= n; i++) {                                        \
  43          GLuint idx = inlist[i];                                        \
  44          GLfloat dp = CLIP_DOTPROD(idx, A, B, C, D );                   \
  45                                                                         \
  46          clipmask[idxPrev] |= PLANE;                                    \
  47          if (!NEGATIVE(dpPrev)) {                                       \
  48             outlist[outcount++] = idxPrev;                              \
  49             clipmask[idxPrev] &= ~PLANE;                                \
  50          }                                                              \
  51                                                                         \
  52          if (DIFFERENT_SIGNS(dp, dpPrev)) {                             \
  53             GLuint newvert = VB->LastClipped++;                         \
  54             VB->ClipMask[newvert] = 0;                                  \
  55             outlist[outcount++] = newvert;                              \
  56             if (NEGATIVE(dp)) {                                         \
  57                /* Going out of bounds.  Avoid division by zero as we    \
  58                 * know dp != dpPrev from DIFFERENT_SIGNS, above.        \
  59                 */                                                      \
  60                GLfloat t = dp / (dp - dpPrev);                          \
  61                INTERP_4F( t, coord[newvert], coord[idx], coord[idxPrev]); \
  62                interp( ctx, t, newvert, idx, idxPrev, GL_TRUE );        \
  63             } else {                                                    \
  64                /* Coming back in.                                       \
  65                 */                                                      \
  66                GLfloat t = dpPrev / (dpPrev - dp);                      \
  67                INTERP_4F( t, coord[newvert], coord[idxPrev], coord[idx]); \
  68                interp( ctx, t, newvert, idxPrev, idx, GL_FALSE );       \
  69             }                                                           \
  70          }                                                              \
  71                                                                         \
  72          idxPrev = idx;                                                 \
  73          dpPrev = dp;                                                   \
  74       }                                                                 \
  75                                                                         \
  76       if (outcount < 3)                                                 \
  77          return;                                                        \
  78                                                                         \
  79       {                                                                 \
  80          GLuint *tmp = inlist;                                          \
  81          inlist = outlist;                                              \
  82          outlist = tmp;                                                 \
  83          n = outcount;                                                  \
  84       }                                                                 \
  85    }                                                                    \
  86 } while (0)
  87
  88
  89 #define LINE_CLIP(PLANE, A, B, C, D )                                   \
  90 do {                                                                    \
  91    if (mask & PLANE) {                                                  \
  92       GLfloat dpI = CLIP_DOTPROD( ii, A, B, C, D );                     \
  93       GLfloat dpJ = CLIP_DOTPROD( jj, A, B, C, D );                     \
  94                                                                         \
  95       if (DIFFERENT_SIGNS(dpI, dpJ)) {                                  \
  96          GLuint newvert = VB->LastClipped++;                            \
  97          VB->ClipMask[newvert] = 0;                                     \
  98          if (NEGATIVE(dpJ)) {                                           \
  99             GLfloat t = dpI / (dpI - dpJ);                              \
 100             VB->ClipMask[jj] |= PLANE;                                  \
 101             INTERP_4F( t, coord[newvert], coord[ii], coord[jj] );       \
 102             interp( ctx, t, newvert, ii, jj, GL_FALSE );                \
 103             jj = newvert;                                               \
 104          } else {                                                       \
 105             GLfloat t = dpJ / (dpJ - dpI);                              \
 106             VB->ClipMask[ii] |= PLANE;                                  \
 107             INTERP_4F( t, coord[newvert], coord[jj], coord[ii] );       \
 108             interp( ctx, t, newvert, jj, ii, GL_FALSE );                \
 109             ii = newvert;                                               \
 110          }                                                              \
 111       }                                                                 \
 112       else if (NEGATIVE(dpI))                                           \
 113          return;                                                        \
 114   }                                                                     \
 115 } while (0)
 116
 117
 118
 119 /* Clip a line against the viewport and user clip planes.
 120  */
 121 static INLINE void
 122 TAG(clip_line)( GLcontext *ctx, GLuint i, GLuint j, GLubyte mask )
 123 {
 124    TNLcontext *tnl = TNL_CONTEXT(ctx);
 125    struct vertex_buffer *VB = &tnl->vb;
 126    interp_func interp = tnl->Driver.Render.Interp;
 127    GLfloat (*coord)[4] = VB->ClipPtr->data;
 128    GLuint ii = i, jj = j, p;
 129
 130    VB->LastClipped = VB->FirstClipped;
 131
 132    if (mask & 0x3f) {
 133       LINE_CLIP( CLIP_RIGHT_BIT,  -1,  0,  0, 1 );
 134       LINE_CLIP( CLIP_LEFT_BIT,    1,  0,  0, 1 );
 135       LINE_CLIP( CLIP_TOP_BIT,     0, -1,  0, 1 );
 136       LINE_CLIP( CLIP_BOTTOM_BIT,  0,  1,  0, 1 );
 137       LINE_CLIP( CLIP_FAR_BIT,     0,  0, -1, 1 );
 138       LINE_CLIP( CLIP_NEAR_BIT,    0,  0,  1, 1 );
 139    }
 140
 141    if (mask & CLIP_USER_BIT) {
 142       for (p=0;p<MAX_CLIP_PLANES;p++) {
 143          if (ctx->Transform.ClipEnabled[p]) {
 144             GLfloat a = ctx->Transform._ClipUserPlane[p][0];
 145             GLfloat b = ctx->Transform._ClipUserPlane[p][1];
 146             GLfloat c = ctx->Transform._ClipUserPlane[p][2];
 147             GLfloat d = ctx->Transform._ClipUserPlane[p][3];
 148             LINE_CLIP( CLIP_USER_BIT, a, b, c, d );
 149          }
 150       }
 151    }
 152
 153    if ((ctx->_TriangleCaps & DD_FLATSHADE) && j != jj)
 154       tnl->Driver.Render.CopyPV( ctx, jj, j );
 155
 156    tnl->Driver.Render.ClippedLine( ctx, ii, jj );
 157 }
 158
 159
 160 /* Clip a triangle against the viewport and user clip planes.
 161  */
 162 static INLINE void
 163 TAG(clip_tri)( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLubyte mask )
 164 {
 165    TNLcontext *tnl = TNL_CONTEXT(ctx);
 166    struct vertex_buffer *VB = &tnl->vb;
 167    interp_func interp = tnl->Driver.Render.Interp;
 168    GLfloat (*coord)[4] = VB->ClipPtr->data;
 169    GLuint pv = v2;
 170    GLuint vlist[2][MAX_CLIPPED_VERTICES];
 171    GLuint *inlist = vlist[0], *outlist = vlist[1];
 172    GLuint p;
 173    GLubyte *clipmask = VB->ClipMask;
 174    GLuint n = 3;
 175
 176    ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */
 177
 178    VB->LastClipped = VB->FirstClipped;
 179
 180    if (mask & 0x3f) {
 181       POLY_CLIP( CLIP_RIGHT_BIT,  -1,  0,  0, 1 );
 182       POLY_CLIP( CLIP_LEFT_BIT,    1,  0,  0, 1 );
 183       POLY_CLIP( CLIP_TOP_BIT,     0, -1,  0, 1 );
 184       POLY_CLIP( CLIP_BOTTOM_BIT,  0,  1,  0, 1 );
 185       POLY_CLIP( CLIP_FAR_BIT,     0,  0, -1, 1 );
 186       POLY_CLIP( CLIP_NEAR_BIT,    0,  0,  1, 1 );
 187    }
 188
 189    if (mask & CLIP_USER_BIT) {
 190       for (p=0;p<MAX_CLIP_PLANES;p++) {
 191          if (ctx->Transform.ClipEnabled[p]) {
 192             GLfloat a = ctx->Transform._ClipUserPlane[p][0];
 193             GLfloat b = ctx->Transform._ClipUserPlane[p][1];
 194             GLfloat c = ctx->Transform._ClipUserPlane[p][2];
 195             GLfloat d = ctx->Transform._ClipUserPlane[p][3];
 196             POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
 197          }
 198       }
 199    }
 200
 201    if (ctx->_TriangleCaps & DD_FLATSHADE) {
 202       if (pv != inlist[0]) {
 203          ASSERT( inlist[0] >= VB->FirstClipped );
 204          tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
 205       }
 206    }
 207
 208    tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
 209 }
 210
 211
 212 /* Clip a quad against the viewport and user clip planes.
 213  */
 214 static INLINE void
 215 TAG(clip_quad)( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint v3,
 216                 GLubyte mask )
 217 {
 218    TNLcontext *tnl = TNL_CONTEXT(ctx);
 219    struct vertex_buffer *VB = &tnl->vb;
 220    interp_func interp = tnl->Driver.Render.Interp;
 221    GLfloat (*coord)[4] = VB->ClipPtr->data;
 222    GLuint pv = v3;
 223    GLuint vlist[2][MAX_CLIPPED_VERTICES];
 224    GLuint *inlist = vlist[0], *outlist = vlist[1];
 225    GLuint p;
 226    GLubyte *clipmask = VB->ClipMask;
 227    GLuint n = 4;
 228
 229    ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */
 230
 231    VB->LastClipped = VB->FirstClipped;
 232
 233    if (mask & 0x3f) {
 234       POLY_CLIP( CLIP_RIGHT_BIT,  -1,  0,  0, 1 );
 235       POLY_CLIP( CLIP_LEFT_BIT,    1,  0,  0, 1 );
 236       POLY_CLIP( CLIP_TOP_BIT,     0, -1,  0, 1 );
 237       POLY_CLIP( CLIP_BOTTOM_BIT,  0,  1,  0, 1 );
 238       POLY_CLIP( CLIP_FAR_BIT,     0,  0, -1, 1 );
 239       POLY_CLIP( CLIP_NEAR_BIT,    0,  0,  1, 1 );
 240    }
 241
 242    if (mask & CLIP_USER_BIT) {
 243       for (p=0;p<MAX_CLIP_PLANES;p++) {
 244          if (ctx->Transform.ClipEnabled[p]) {
 245             GLfloat a = ctx->Transform._ClipUserPlane[p][0];
 246             GLfloat b = ctx->Transform._ClipUserPlane[p][1];
 247             GLfloat c = ctx->Transform._ClipUserPlane[p][2];
 248             GLfloat d = ctx->Transform._ClipUserPlane[p][3];
 249             POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
 250          }
 251       }
 252    }
 253
 254    if (ctx->_TriangleCaps & DD_FLATSHADE) {
 255       if (pv != inlist[0]) {
 256          ASSERT( inlist[0] >= VB->FirstClipped );
 257          tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
 258       }
 259    }
 260
 261    tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
 262 }
 263
 264 #undef W
 265 #undef Z
 266 #undef Y
 267 #undef X
 268 #undef SIZE
 269 #undef TAG
 270 #undef POLY_CLIP
 271 #undef LINE_CLIP