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
55void
56Subdivider::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
84void
85Subdivider::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