1 /* 2 * Mesa 3-D graphics library 3 * 4 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included 14 * in all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 22 * OTHER DEALINGS IN THE SOFTWARE. 23 * 24 * Authors: 25 * Keith Whitwell <keithw (at) vmware.com> 26 */ 27 28 29 #define CLIP_DOTPROD(K, A, B, C, D) X(K)*A + Y(K)*B + Z(K)*C + W(K)*D 30 31 #define POLY_CLIP( PLANE_BIT, A, B, C, D ) \ 32 do { \ 33 if (mask & PLANE_BIT) { \ 34 GLuint idxPrev = inlist[0]; \ 35 GLfloat dpPrev = CLIP_DOTPROD(idxPrev, A, B, C, D ); \ 36 GLuint outcount = 0; \ 37 GLuint i; \ 38 \ 39 inlist[n] = inlist[0]; /* prevent rotation of vertices */ \ 40 for (i = 1; i <= n; i++) { \ 41 GLuint idx = inlist[i]; \ 42 GLfloat dp = CLIP_DOTPROD(idx, A, B, C, D ); \ 43 \ 44 if (dpPrev >= 0.0f) { \ 45 outlist[outcount++] = idxPrev; \ 46 } \ 47 \ 48 if (DIFFERENT_SIGNS(dp, dpPrev)) { \ 49 if (dp < 0.0f) { \ 50 /* Going out of bounds. Avoid division by zero as we \ 51 * know dp != dpPrev from DIFFERENT_SIGNS, above. \ 52 */ \ 53 GLfloat t = dp / (dp - dpPrev); \ 54 INTERP_4F( t, coord[newvert], coord[idx], coord[idxPrev]); \ 55 interp( ctx, t, newvert, idx, idxPrev, GL_TRUE ); \ 56 } else { \ 57 /* Coming back in. \ 58 */ \ 59 GLfloat t = dpPrev / (dpPrev - dp); \ 60 INTERP_4F( t, coord[newvert], coord[idxPrev], coord[idx]); \ 61 interp( ctx, t, newvert, idxPrev, idx, GL_FALSE ); \ 62 } \ 63 outlist[outcount++] = newvert++; \ 64 } \ 65 \ 66 idxPrev = idx; \ 67 dpPrev = dp; \ 68 } \ 69 \ 70 if (outcount < 3) \ 71 return; \ 72 \ 73 { \ 74 GLuint *tmp = inlist; \ 75 inlist = outlist; \ 76 outlist = tmp; \ 77 n = outcount; \ 78 } \ 79 } \ 80 } while (0) 81 82 83 #define LINE_CLIP(PLANE_BIT, A, B, C, D ) \ 84 do { \ 85 if (mask & PLANE_BIT) { \ 86 const GLfloat dp0 = CLIP_DOTPROD( v0, A, B, C, D ); \ 87 const GLfloat dp1 = CLIP_DOTPROD( v1, A, B, C, D ); \ 88 const GLboolean neg_dp0 = dp0 < 0.0f; \ 89 const GLboolean neg_dp1 = dp1 < 0.0f; \ 90 \ 91 /* For regular clipping, we know from the clipmask that one \ 92 * (or both) of these must be negative (otherwise we wouldn't \ 93 * be here). \ 94 * For userclip, there is only a single bit for all active \ 95 * planes, so we can end up here when there is nothing to do, \ 96 * hence the second < 0.0f test: \ 97 */ \ 98 if (neg_dp0 && neg_dp1) \ 99 return; /* both vertices outside clip plane: discard */ \ 100 \ 101 if (neg_dp1) { \ 102 GLfloat t = dp1 / (dp1 - dp0); \ 103 if (t > t1) t1 = t; \ 104 } else if (neg_dp0) { \ 105 GLfloat t = dp0 / (dp0 - dp1); \ 106 if (t > t0) t0 = t; \ 107 } \ 108 if (t0 + t1 >= 1.0) \ 109 return; /* discard */ \ 110 } \ 111 } while (0) 112 113 114 115 /* Clip a line against the viewport and user clip planes. 116 */ 117 static inline void 118 TAG(clip_line)( struct gl_context *ctx, GLuint v0, GLuint v1, GLubyte mask ) 119 { 120 TNLcontext *tnl = TNL_CONTEXT(ctx); 121 struct vertex_buffer *VB = &tnl->vb; 122 tnl_interp_func interp = tnl->Driver.Render.Interp; 123 GLfloat (*coord)[4] = VB->ClipPtr->data; 124 GLuint newvert = VB->Count; 125 GLfloat t0 = 0; 126 GLfloat t1 = 0; 127 const GLuint v0_orig = v0; 128 129 if (mask & CLIP_FRUSTUM_BITS) { 130 LINE_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); 131 LINE_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 ); 132 LINE_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 ); 133 LINE_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 ); 134 LINE_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 ); 135 LINE_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 ); 136 } 137 138 if (mask & CLIP_USER_BIT) { 139 GLbitfield enabled = ctx->Transform.ClipPlanesEnabled; 140 while (enabled) { 141 const int p = u_bit_scan(&enabled); 142 const GLfloat a = ctx->Transform._ClipUserPlane[p][0]; 143 const GLfloat b = ctx->Transform._ClipUserPlane[p][1]; 144 const GLfloat c = ctx->Transform._ClipUserPlane[p][2]; 145 const GLfloat d = ctx->Transform._ClipUserPlane[p][3]; 146 LINE_CLIP( CLIP_USER_BIT, a, b, c, d ); 147 } 148 } 149 150 if (VB->ClipMask[v0]) { 151 INTERP_4F( t0, coord[newvert], coord[v0], coord[v1] ); 152 interp( ctx, t0, newvert, v0, v1, GL_FALSE ); 153 v0 = newvert; 154 newvert++; 155 } 156 else { 157 assert(t0 == 0.0); 158 } 159 160 /* Note: we need to use vertex v0_orig when computing the new 161 * interpolated/clipped vertex position, not the current v0 which 162 * may have got set when we clipped the other end of the line! 163 */ 164 if (VB->ClipMask[v1]) { 165 INTERP_4F( t1, coord[newvert], coord[v1], coord[v0_orig] ); 166 interp( ctx, t1, newvert, v1, v0_orig, GL_FALSE ); 167 168 if (ctx->Light.ShadeModel == GL_FLAT) 169 tnl->Driver.Render.CopyPV( ctx, newvert, v1 ); 170 171 v1 = newvert; 172 173 newvert++; 174 } 175 else { 176 assert(t1 == 0.0); 177 } 178 179 tnl->Driver.Render.ClippedLine( ctx, v0, v1 ); 180 } 181 182 183 /* Clip a triangle against the viewport and user clip planes. 184 */ 185 static inline void 186 TAG(clip_tri)( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLubyte mask ) 187 { 188 TNLcontext *tnl = TNL_CONTEXT(ctx); 189 struct vertex_buffer *VB = &tnl->vb; 190 tnl_interp_func interp = tnl->Driver.Render.Interp; 191 GLuint newvert = VB->Count; 192 GLfloat (*coord)[4] = VB->ClipPtr->data; 193 GLuint pv = v2; 194 GLuint vlist[2][MAX_CLIPPED_VERTICES]; 195 GLuint *inlist = vlist[0], *outlist = vlist[1]; 196 GLuint n = 3; 197 198 ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */ 199 200 if (0) { 201 /* print pre-clip vertex coords */ 202 GLuint i, j; 203 printf("pre clip:\n"); 204 for (i = 0; i < n; i++) { 205 j = inlist[i]; 206 printf(" %u: %u: %f, %f, %f, %f\n", 207 i, j, 208 coord[j][0], coord[j][1], coord[j][2], coord[j][3]); 209 assert(!IS_INF_OR_NAN(coord[j][0])); 210 assert(!IS_INF_OR_NAN(coord[j][1])); 211 assert(!IS_INF_OR_NAN(coord[j][2])); 212 assert(!IS_INF_OR_NAN(coord[j][3])); 213 } 214 } 215 216 217 if (mask & CLIP_FRUSTUM_BITS) { 218 POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); 219 POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 ); 220 POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 ); 221 POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 ); 222 POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 ); 223 POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 ); 224 } 225 226 if (mask & CLIP_USER_BIT) { 227 GLbitfield enabled = ctx->Transform.ClipPlanesEnabled; 228 while (enabled) { 229 const int p = u_bit_scan(&enabled); 230 const GLfloat a = ctx->Transform._ClipUserPlane[p][0]; 231 const GLfloat b = ctx->Transform._ClipUserPlane[p][1]; 232 const GLfloat c = ctx->Transform._ClipUserPlane[p][2]; 233 const GLfloat d = ctx->Transform._ClipUserPlane[p][3]; 234 POLY_CLIP( CLIP_USER_BIT, a, b, c, d ); 235 } 236 } 237 238 if (ctx->Light.ShadeModel == GL_FLAT) { 239 if (pv != inlist[0]) { 240 assert( inlist[0] >= VB->Count ); 241 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv ); 242 } 243 } 244 245 if (0) { 246 /* print post-clip vertex coords */ 247 GLuint i, j; 248 printf("post clip:\n"); 249 for (i = 0; i < n; i++) { 250 j = inlist[i]; 251 printf(" %u: %u: %f, %f, %f, %f\n", 252 i, j, 253 coord[j][0], coord[j][1], coord[j][2], coord[j][3]); 254 } 255 } 256 257 tnl->Driver.Render.ClippedPolygon( ctx, inlist, n ); 258 } 259 260 261 /* Clip a quad against the viewport and user clip planes. 262 */ 263 static inline void 264 TAG(clip_quad)( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint v3, 265 GLubyte mask ) 266 { 267 TNLcontext *tnl = TNL_CONTEXT(ctx); 268 struct vertex_buffer *VB = &tnl->vb; 269 tnl_interp_func interp = tnl->Driver.Render.Interp; 270 GLuint newvert = VB->Count; 271 GLfloat (*coord)[4] = VB->ClipPtr->data; 272 GLuint pv = v3; 273 GLuint vlist[2][MAX_CLIPPED_VERTICES]; 274 GLuint *inlist = vlist[0], *outlist = vlist[1]; 275 GLuint n = 4; 276 277 ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */ 278 279 if (mask & CLIP_FRUSTUM_BITS) { 280 POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); 281 POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 ); 282 POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 ); 283 POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 ); 284 POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 ); 285 POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 ); 286 } 287 288 if (mask & CLIP_USER_BIT) { 289 GLbitfield enabled = ctx->Transform.ClipPlanesEnabled; 290 while (enabled) { 291 const int p = u_bit_scan(&enabled); 292 const GLfloat a = ctx->Transform._ClipUserPlane[p][0]; 293 const GLfloat b = ctx->Transform._ClipUserPlane[p][1]; 294 const GLfloat c = ctx->Transform._ClipUserPlane[p][2]; 295 const GLfloat d = ctx->Transform._ClipUserPlane[p][3]; 296 POLY_CLIP( CLIP_USER_BIT, a, b, c, d ); 297 } 298 } 299 300 if (ctx->Light.ShadeModel == GL_FLAT) { 301 if (pv != inlist[0]) { 302 assert( inlist[0] >= VB->Count ); 303 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv ); 304 } 305 } 306 307 tnl->Driver.Render.ClippedPolygon( ctx, inlist, n ); 308 } 309 310 #undef W 311 #undef Z 312 #undef Y 313 #undef X 314 #undef SIZE 315 #undef TAG 316 #undef POLY_CLIP 317 #undef LINE_CLIP 318
