FreeWRL / FreeX3D 4.3.0
curvesub.cc
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 "curve.h"
49#include "nurbsconsts.h"
50
51/*--------------------------------------------------------------------------
52 * drawCurves - main curve rendering entry point
53 *--------------------------------------------------------------------------
54 */
55
56void
57Subdivider::drawCurves( void )
58{
59 REAL from[1], to[1];
60 Flist bpts;
61 qlist->getRange( from, to, bpts );
62
63 renderhints.init( );
64
65 backend.bgncurv();
66 for( int i=bpts.start; i<bpts.end-1; i++ ) {
67 REAL pta, ptb;
68 pta = bpts.pts[i];
69 ptb = bpts.pts[i+1];
70
71 qlist->downloadAll( &pta, &ptb, backend );
72
73 Curvelist curvelist( qlist, pta, ptb );
74 samplingSplit( curvelist, renderhints.maxsubdivisions );
75 }
76 backend.endcurv();
77}
78
79
80/*--------------------------------------------------------------------------
81 * samplingSplit - recursively subdivide patch, cull check each subpatch
82 *--------------------------------------------------------------------------
83 */
84
85void
86Subdivider::samplingSplit( Curvelist& curvelist, int subdivisions )
87{
88 if( curvelist.cullCheck() == CULL_TRIVIAL_REJECT ) return;
89
90 curvelist.getstepsize();
91
92 if( curvelist.needsSamplingSubdivision() && (subdivisions > 0) ) {
93 REAL mid = ( curvelist.range[0] + curvelist.range[1] ) * 0.5;
94 Curvelist lowerlist( curvelist, mid );
95 samplingSplit( lowerlist, subdivisions-1 ); // lower
96 samplingSplit( curvelist, subdivisions-1 ); // upper
97 } else {
98 long nu = 1 + ((long) (curvelist.range[2] / curvelist.stepsize));
99 backend.curvgrid( curvelist.range[0], curvelist.range[1], nu );
100 backend.curvmesh( 0, nu );
101 }
102}
103
Definition flist.h:42