OSG屏幕坐标转世界坐标

 1 static osg::Matrix getScreenToWorldMatrix(osg::View *view)
 2 {
 3     return osg::Matrix::inverse(getWorldToScreenMatrix(view));
 4 }
 5 
 6 static osg::Matrix getWorldToScreenMatrix(osg::View *view)
 7 {
 8     auto camera = view->getCamera();
 9     auto view_matrix = camera->getViewMatrix();
10     auto proj_matrix = camera->getProjectionMatrix();
11     auto vp = camera->getViewport();
12     auto screen_matrix = vp->computeWindowMatrix();
13 
14     return view_matrix * proj_matrix * screen_matrix;
15 }
16 
17 static osg::Vec3 ndcPointToWorld(osg::View *view, const osg::Vec2 &pt)
18 {
19     auto camera = view->getCamera();
20     auto view_matrix = camera->getViewMatrix();
21     auto proj_matrix = camera->getProjectionMatrix();
22     auto vp_matrix = view_matrix * proj_matrix;
23     auto pv_matrix = osg::Matrix::inverse(vp_matrix);
24 
25     auto world_pt = osg::Vec3(pt, 0) * pv_matrix;
26     return world_pt;
27 }
28 
29 static osg::Vec3 screenPointToWorld(osg::View *view, const osg::Vec2 &pt)
30 {
31     auto camera = view->getCamera();
32     auto view_matrix = camera->getViewMatrix();
33     auto proj_matrix = camera->getProjectionMatrix();
34     auto vp = camera->getViewport();
35     auto screen_matrix = vp->computeWindowMatrix();
36     auto vps_matrix = view_matrix * proj_matrix * screen_matrix;
37     auto spv_matrix = osg::Matrix::inverse(vps_matrix);
38 
39     // QT 及 Windows窗口坐标系统原点(0,0)在左上角，OpenGL默认在左下角，注意D3D在左上角
40     auto world_pt = osg::Vec3(pt.x(), vp->y() - pt.y(), 0);
41     world_pt = world_pt * spv_matrix;
42     return world_pt;
43 }
44 
45 static osg::Vec2 screenPointToNdc(osg::View* view, const osg::Vec2& pt){
46     auto camera = view->getCamera();
47     auto vp = camera->getViewport();
48     auto ndc_pt = osg::Vec2(pt.x(), vp->y() - pt.y());
49     auto x = ndc_pt.x() * 2. / vp->x() - 1.;
50     auto y = 1. - (2. * ndc_pt.y() / vp->y());
51     return osg::Vec2(x, y);
52 }