1 /* 2 ** License Applicability. Except to the extent portions of this file are 3 ** made subject to an alternative license as permitted in the SGI Free 4 ** Software License B, Version 1.1 (the "License"), the contents of this 5 ** file are subject only to the provisions of the License. You may not use 6 ** this file except in compliance with the License. You may obtain a copy 7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600 8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at: 9 ** 10 ** http://oss.sgi.com/projects/FreeB 11 ** 12 ** Note that, as provided in the License, the Software is distributed on an 13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS 14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND 15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A 16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT. 17 ** 18 ** Original Code. The Original Code is: OpenGL Sample Implementation, 19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics, 20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc. 21 ** Copyright in any portions created by third parties is as indicated 22 ** elsewhere herein. All Rights Reserved. 23 ** 24 ** Additional Notice Provisions: The application programming interfaces 25 ** established by SGI in conjunction with the Original Code are The 26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released 27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version 28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X 29 ** Window System(R) (Version 1.3), released October 19, 1998. This software 30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation 31 ** published by SGI, but has not been independently verified as being 32 ** compliant with the OpenGL(R) version 1.2.1 Specification. 33 */ 34 35 /* 36 * curvesub.c++ 37 * 38 */ 39 40 #include "glimports.h" 41 #include "myassert.h" 42 #include "mystdio.h" 43 #include "subdivider.h" 44 #include "renderhints.h" 45 #include "backend.h" 46 #include "quilt.h" 47 #include "curvelist.h" 48 //#include "nurbsconsts.h" 49 50 /*-------------------------------------------------------------------------- 51 * drawCurves - main curve rendering entry point 52 *-------------------------------------------------------------------------- 53 */ 54 55 void 56 Subdivider::drawCurves( void ) 57 { 58 REAL from[1], to[1]; 59 Flist bpts; 60 qlist->getRange( from, to, bpts ); 61 62 renderhints.init( ); 63 64 backend.bgncurv(); 65 for( int i=bpts.start; i<bpts.end-1; i++ ) { 66 REAL pta, ptb; 67 pta = bpts.pts[i]; 68 ptb = bpts.pts[i+1]; 69 70 qlist->downloadAll( &pta, &ptb, backend ); 71 72 Curvelist curvelist( qlist, pta, ptb ); 73 samplingSplit( curvelist, renderhints.maxsubdivisions ); 74 } 75 backend.endcurv(); 76 } 77 78 79 /*-------------------------------------------------------------------------- 80 * samplingSplit - recursively subdivide patch, cull check each subpatch 81 *-------------------------------------------------------------------------- 82 */ 83 84 void 85 Subdivider::samplingSplit( Curvelist& curvelist, int subdivisions ) 86 { 87 if( curvelist.cullCheck() == CULL_TRIVIAL_REJECT ) return; 88 89 curvelist.getstepsize(); 90 91 if( curvelist.needsSamplingSubdivision() && (subdivisions > 0) ) { 92 REAL mid = ( curvelist.range[0] + curvelist.range[1] ) * 0.5; 93 Curvelist lowerlist( curvelist, mid ); 94 samplingSplit( lowerlist, subdivisions-1 ); // lower 95 samplingSplit( curvelist, subdivisions-1 ); // upper 96 } else { 97 long nu = 1 + ((long) (curvelist.range[2] / curvelist.stepsize)); 98 backend.curvgrid( curvelist.range[0], curvelist.range[1], nu ); 99 backend.curvmesh( 0, nu ); 100 } 101 } 102 103