1 /* 2 * Mesa 3-D graphics library 3 * Version: 6.5.2 4 * 5 * Copyright (C) 1999-2006 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 * Authors: 25 * Keith Whitwell <keith (at) tungstengraphics.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 (!IS_NEGATIVE(dpPrev)) { \ 45 outlist[outcount++] = idxPrev; \ 46 } \ 47 \ 48 if (DIFFERENT_SIGNS(dp, dpPrev)) { \ 49 if (IS_NEGATIVE(dp)) { \ 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 = IS_NEGATIVE(dp0); \ 89 const GLboolean neg_dp1 = IS_NEGATIVE(dp1); \ 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 IS_NEGATIVE() 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 GLuint p; 128 const GLuint v0_orig = v0; 129 130 if (mask & CLIP_FRUSTUM_BITS) { 131 LINE_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); 132 LINE_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 ); 133 LINE_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 ); 134 LINE_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 ); 135 LINE_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 ); 136 LINE_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 ); 137 } 138 139 if (mask & CLIP_USER_BIT) { 140 for (p = 0; p < ctx->Const.MaxClipPlanes; p++) { 141 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) { 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 } 150 151 if (VB->ClipMask[v0]) { 152 INTERP_4F( t0, coord[newvert], coord[v0], coord[v1] ); 153 interp( ctx, t0, newvert, v0, v1, GL_FALSE ); 154 v0 = newvert; 155 newvert++; 156 } 157 else { 158 ASSERT(t0 == 0.0); 159 } 160 161 /* Note: we need to use vertex v0_orig when computing the new 162 * interpolated/clipped vertex position, not the current v0 which 163 * may have got set when we clipped the other end of the line! 164 */ 165 if (VB->ClipMask[v1]) { 166 INTERP_4F( t1, coord[newvert], coord[v1], coord[v0_orig] ); 167 interp( ctx, t1, newvert, v1, v0_orig, GL_FALSE ); 168 169 if (ctx->Light.ShadeModel == GL_FLAT) 170 tnl->Driver.Render.CopyPV( ctx, newvert, v1 ); 171 172 v1 = newvert; 173 174 newvert++; 175 } 176 else { 177 ASSERT(t1 == 0.0); 178 } 179 180 tnl->Driver.Render.ClippedLine( ctx, v0, v1 ); 181 } 182 183 184 /* Clip a triangle against the viewport and user clip planes. 185 */ 186 static inline void 187 TAG(clip_tri)( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLubyte mask ) 188 { 189 TNLcontext *tnl = TNL_CONTEXT(ctx); 190 struct vertex_buffer *VB = &tnl->vb; 191 tnl_interp_func interp = tnl->Driver.Render.Interp; 192 GLuint newvert = VB->Count; 193 GLfloat (*coord)[4] = VB->ClipPtr->data; 194 GLuint pv = v2; 195 GLuint vlist[2][MAX_CLIPPED_VERTICES]; 196 GLuint *inlist = vlist[0], *outlist = vlist[1]; 197 GLuint p; 198 GLuint n = 3; 199 200 ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */ 201 202 if (0) { 203 /* print pre-clip vertex coords */ 204 GLuint i, j; 205 printf("pre clip:\n"); 206 for (i = 0; i < n; i++) { 207 j = inlist[i]; 208 printf(" %u: %u: %f, %f, %f, %f\n", 209 i, j, 210 coord[j][0], coord[j][1], coord[j][2], coord[j][3]); 211 assert(!IS_INF_OR_NAN(coord[j][0])); 212 assert(!IS_INF_OR_NAN(coord[j][1])); 213 assert(!IS_INF_OR_NAN(coord[j][2])); 214 assert(!IS_INF_OR_NAN(coord[j][3])); 215 } 216 } 217 218 219 if (mask & CLIP_FRUSTUM_BITS) { 220 POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); 221 POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 ); 222 POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 ); 223 POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 ); 224 POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 ); 225 POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 ); 226 } 227 228 if (mask & CLIP_USER_BIT) { 229 for (p = 0; p < ctx->Const.MaxClipPlanes; p++) { 230 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) { 231 const GLfloat a = ctx->Transform._ClipUserPlane[p][0]; 232 const GLfloat b = ctx->Transform._ClipUserPlane[p][1]; 233 const GLfloat c = ctx->Transform._ClipUserPlane[p][2]; 234 const GLfloat d = ctx->Transform._ClipUserPlane[p][3]; 235 POLY_CLIP( CLIP_USER_BIT, a, b, c, d ); 236 } 237 } 238 } 239 240 if (ctx->Light.ShadeModel == GL_FLAT) { 241 if (pv != inlist[0]) { 242 ASSERT( inlist[0] >= VB->Count ); 243 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv ); 244 } 245 } 246 247 if (0) { 248 /* print post-clip vertex coords */ 249 GLuint i, j; 250 printf("post clip:\n"); 251 for (i = 0; i < n; i++) { 252 j = inlist[i]; 253 printf(" %u: %u: %f, %f, %f, %f\n", 254 i, j, 255 coord[j][0], coord[j][1], coord[j][2], coord[j][3]); 256 } 257 } 258 259 tnl->Driver.Render.ClippedPolygon( ctx, inlist, n ); 260 } 261 262 263 /* Clip a quad against the viewport and user clip planes. 264 */ 265 static inline void 266 TAG(clip_quad)( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint v3, 267 GLubyte mask ) 268 { 269 TNLcontext *tnl = TNL_CONTEXT(ctx); 270 struct vertex_buffer *VB = &tnl->vb; 271 tnl_interp_func interp = tnl->Driver.Render.Interp; 272 GLuint newvert = VB->Count; 273 GLfloat (*coord)[4] = VB->ClipPtr->data; 274 GLuint pv = v3; 275 GLuint vlist[2][MAX_CLIPPED_VERTICES]; 276 GLuint *inlist = vlist[0], *outlist = vlist[1]; 277 GLuint p; 278 GLuint n = 4; 279 280 ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */ 281 282 if (mask & CLIP_FRUSTUM_BITS) { 283 POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 ); 284 POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 ); 285 POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 ); 286 POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 ); 287 POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 ); 288 POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 ); 289 } 290 291 if (mask & CLIP_USER_BIT) { 292 for (p = 0; p < ctx->Const.MaxClipPlanes; p++) { 293 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) { 294 const GLfloat a = ctx->Transform._ClipUserPlane[p][0]; 295 const GLfloat b = ctx->Transform._ClipUserPlane[p][1]; 296 const GLfloat c = ctx->Transform._ClipUserPlane[p][2]; 297 const GLfloat d = ctx->Transform._ClipUserPlane[p][3]; 298 POLY_CLIP( CLIP_USER_BIT, a, b, c, d ); 299 } 300 } 301 } 302 303 if (ctx->Light.ShadeModel == GL_FLAT) { 304 if (pv != inlist[0]) { 305 ASSERT( inlist[0] >= VB->Count ); 306 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv ); 307 } 308 } 309 310 tnl->Driver.Render.ClippedPolygon( ctx, inlist, n ); 311 } 312 313 #undef W 314 #undef Z 315 #undef Y 316 #undef X 317 #undef SIZE 318 #undef TAG 319 #undef POLY_CLIP 320 #undef LINE_CLIP 321
