osg实现目标选择 代码实现
时间: 2023-05-23 15:06:56 浏览: 171
A:
osg中可以通过 osg::Projector 类实现目标选择。具体实现步骤如下:
1. 创建 osg::Projector 对象。
```cpp
osg::Camera* camera = new osg::Camera;
osg::Projector* projector = new osg::Projector;
camera->addChild(projector);
```
2. 设置 projector 相关参数。
```cpp
projector->setViewMatrix(osg::Matrix::identity());
projector->setProjectionMatrix(osg::Matrix::identity());
projector->setViewport(0, 0, window_width, window_height);
projector->setTransformHint(osg::Projector::ABSOLUTE_RF);
```
3. 计算屏幕坐标对应的射线。
```cpp
osg::Vec3d start, end;
projector->pickRay(screen_x, screen_y, &start, &end);
osg::Vec3d dir = end - start;
dir.normalize();
```
4. 执行射线与目标的碰撞检测。
```cpp
osgUtil::LineSegmentIntersector::Intersections
results;
osgUtil::LineSegmentIntersector* intersector
= new osgUtil::LineSegmentIntersector(start, end);
osgUtil::IntersectionVisitor iv(intersector);
iv.setTraversalMask(TRAVMASK_PICKABLE);
root->accept(iv);
if (intersector->containsIntersections())
{
osgUtil::LineSegmentIntersector::Intersection
first = *(intersector->getIntersections().begin());
osg::NodePath& nodePath = first.nodePath;
// 目标被选中
}
else
{
// 目标未被选中
}
```
其中,screen_x 和 screen_y 为屏幕坐标,root 为场景根节点,TRAVMASK_PICKABLE 是指定目标节点的遍历掩码,用于过滤不可选中的节点。
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