osgPresentation.HUDTransform

osgPresentation.HUDTransform 是 OpenSceneGraph 中的一个类，用于将 2D 的 HUD（头顶显示器）元素添加到场景中，实现可视化的效果。

继承关系

osg::Transform -> osgPresentation::HUDTransform

头文件

#include <osgPresentation/HUDTransform>

构造函数

• HUDTransform()
• HUDTransform(const osgPresentation::HUDTransform &ht, const osg::CopyOp &copyop = osg::CopyOp::SHALLOW_COPY)

主要函数

• bool addChild(osg::Node *child) 加入一个子节点（用于装载HUD元素）
• bool removeChild(osg::Node *child) 移除一个子节点（用于移除HUD元素）
• void setProjectionMatrix(const osg::Matrixd &matrix) 设置传入矩阵作为HUD节点的投影矩阵
• osg::Matrixd getProjectionMatrix() const 返回当前的投影矩阵

示例

osg::ref_ptr<osg::Group> root = new osg::Group;
osg::ref_ptr<osg::Geode> geode = new osg::Geode;
osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry;
osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;

vertices->push_back(osg::Vec3d( 0, 0, 0));
vertices->push_back(osg::Vec3d( 0, 0, 10));
vertices->push_back(osg::Vec3d(10, 0, 10));
vertices->push_back(osg::Vec3d(10, 0, 0));

geometry->setVertexArray(vertices.get());
geometry->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS, 0, 4));

geode->addDrawable(geometry.get());
root->addChild(geode);

osgPresentation::View* view = new osgPresentation::View;

// 创建一个HUDTexture
osg::Image* image = osgDB::readImageFile("image.png");
osg::ref_ptr<osg::Texture2D> texture = new osg::Texture2D(image);
texture->setResizeNonPowerOfTwoHint(false);
texture->setDataVariance(osg::Object::DYNAMIC);
texture->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
texture->setFilter(osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR);

osg::Geometry* quad = osg::createTexturedQuadGeometry(osg::Vec3(-1.f, 0.f, -1.f), osg::Vec3(2.f, 0.f, 0.f), osg::Vec3(0.f, 0.f, 2.f));
osgPresentation::HUDTexture* hudtex = new osgPresentation::HUDTexture();
hudtex->setTexture(texture);
hudtex->addChild(quad);

osgPresentation::HUDTransform* hudTrans = new osgPresentation::HUDTransform();
hudTrans->setProjectionMatrix(osg::Matrix::ortho2D(0, image->s(), 0, image->t()));
hudTrans->addChild(hudtex);

view->getCamera()->addChild(hudTrans);

参考

• OpenSceneGraph Documentation