繪制并渲染幾何體主要有一下3步：
1.創(chuàng)建各種向量數(shù)據(jù)，例如頂點、紋理坐標(biāo)、顏色、法線<逆時針添加坐標(biāo)數(shù)據(jù)>.
2.實例化一個幾何體對象（osg::geometry）,設(shè)置頂點坐標(biāo)數(shù)組、紋理坐標(biāo)數(shù)組、顏色坐標(biāo)數(shù)組、法線數(shù)組、綁定方式及數(shù)據(jù)解析格式.
3.加入葉節(jié)點繪制渲染.
基本繪制：
1
#include <osgViewer/Viewer>
2
3#include <osg/Node>
4#include <osg/Geode>
5#include <osg/Group>
6
7#include <osgDB/ReadFile>
8#include <osgDB/WriteFile>
9
10#include <osgUtil/Optimizer>
11
12//創(chuàng)建一個四邊形節(jié)點
13
osg::ref_ptr <osg::Node >cteateQuad()
{
14
//創(chuàng)建一個葉節(jié)點對象
15 osg::ref_ptr <osg::Geode > geode = new osg::Geode ();
16 //創(chuàng)建一個幾何體對象
17 osg::ref_ptr <osg::Geometry >geom=new osg::Geometry ();
18 //添加頂點數(shù)據(jù) 注意頂點的添加順序是逆時針
19 osg::ref_ptr <osg::Vec3Array >v=new osg::Vec3Array ();
20 //添加數(shù)據(jù)
21 v->push_back (osg::Vec3 (0,0,0));
22 v->push_back (osg::Vec3 (1,0,0));
23 v->push_back (osg::Vec3 (1,0,1));
24 v->push_back (osg::Vec3 (0,0,1));
25
26 //設(shè)置頂點數(shù)據(jù)
27 geom->setVertexArray (v.get ());
28
29 //創(chuàng)建紋理訂點數(shù)據(jù)
30 osg::ref_ptr <osg::Vec2Array >vt=new osg::Vec2Array ();
31 //添加紋理坐標(biāo)
32 vt->push_back (osg::Vec2 (0,0));
33 vt->push_back (osg::Vec2 (1,0));
34 vt->push_back (osg::Vec2 (1,1));
35 vt->push_back (osg::Vec2 (0,1));
36
37 //設(shè)置紋理坐標(biāo)
38 geom->setTexCoordArray(0,vt.get ());
39
40 //創(chuàng)建顏色數(shù)組
41 osg::ref_ptr <osg::Vec4Array >vc=new osg::Vec4Array ();
42 //添加數(shù)據(jù)
43 vc->push_back (osg::Vec4 (1,0,0,1));
44 vc->push_back (osg::Vec4 (0,1,0,1));
45 vc->push_back (osg::Vec4 (0,0,1,1));
46 vc->push_back (osg::Vec4 (1,1,0,1));
47
48 //設(shè)置顏色數(shù)組
49 geom->setColorArray (vc.get ());
50 //設(shè)置顏色的綁定方式為單個頂點
51 geom->setColorBinding (osg::Geometry ::BIND_PER_VERTEX );
52
53 //創(chuàng)建法線數(shù)組
54 osg::ref_ptr <osg::Vec3Array >nc=new osg::Vec3Array ();
55 //添加法線
56 nc->push_back (osg::Vec3 (0,-1,0));
57 //設(shè)置法線
58 geom->setNormalArray (nc.get ());
59 //設(shè)置法綁定為全部頂點
60 geom->setNormalBinding (osg::Geometry ::BIND_OVERALL );
61 //添加圖元
62 geom->addPrimitiveSet (new osg::DrawArrays (osg::PrimitiveSet ::QUADS ,0,4));
63
64 //添加到葉子節(jié)點
65 geode->addDrawable (geom.get ());
66
67 return geode.get ();
68
69
}
70
71int main(){
72 osg::ref_ptr<osgViewer::Viewer >viewer=new osgViewer::Viewer();
73
74 osg::ref_ptr<osg::Group>root=new osg::Group();
75
76 root->addChild (cteateQuad());
77
78 osgUtil::Optimizer optimizer;
79 optimizer.optimize (root.get ());
80
81 viewer->setSceneData (root.get());
82
83 viewer->realize ();
84
85 viewer->run();
86
87 return 0;
88
89}