FlySky大师的代码示例理解不清，大家来“喷”我吧
#include <osgViewer/Viewer>#include <osg/Node>
#include <osg/Geode>
#include <osg/Group>
#include <osg/Camera>
#include <osg/Matrix>
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgText/Text>
#include <osgText/Font>
#include <osgUtil/Optimizer>
#include <iostream>
osg::ref_ptr<osg::Camera> createAllKindText()
{
osg::ref_ptr<osg::Camera> camera = new osg::Camera() ;
//设置投影矩阵
camera->setProjectionMatrix(osg::Matrix::ortho2D(0,1280,0,800));
//设置视图矩阵
camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
camera->setViewMatrix(osg::Matrix::identity());
//清除深度缓存
camera->setClearMask(GL_DEPTH_BUFFER_BIT);
//设置渲染顺寻，在主摄像机之前渲染
camera->setRenderOrder(osg::Camera::POST_RENDER);
//设置为不接收事件，始终不得到焦点
camera->setAllowEventFocus(false);
osg::ref_ptr<osgText::Font> font = osgText::readFontFile("fonts/arial.ttf");
osg::ref_ptr<osg::Geode> geode= new osg::Geode;
osg::ref_ptr<osg::StateSet> stateset = geode->getOrCreateStateSet();
stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
//-----------------------------------------------//-----------------------------------------------
//设置文字输出的格式
//设置格式为LEFT_TO_RIGHT，从左到右
{
osg::ref_ptr<osgText::Text> text = new osgText::Text;
text->setFont(font.get());
text->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
text->setCharacterSize(20.0f);
text->setPosition(osg::Vec3(50.0f,750.0f,0.0f));
text->setLayout(osgText::Text::LEFT_TO_RIGHT);
text->setText("text->setLayout(osgText::Text::LEFT_TO_RIGHT);");
geode->addDrawable(text.get());
}
//设置格式为RIGHT_TO_LEFT，从右到左
{
osg::ref_ptr<osgText::Text> text = new osgText::Text;
text->setFont(font.get());
text->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
text->setCharacterSize(30.0f);
text->setPosition(osg::Vec3(1200.0f,750.0f,0.0f));
text->setLayout(osgText::Text::RIGHT_TO_LEFT);
text->setAlignment(osgText::Text::RIGHT_BASE_LINE);
text->setText("text->setLayout(osgText::Text::RIGHT_TO_LEFT);");
geode->addDrawable(text.get());
}
//设置格式为VERTICAL，垂直
{
osg::ref_ptr<osgText::Text> text = new osgText::Text;
text->setFont(font.get());
text->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
text->setCharacterSize(20.0f);
text->setPosition(osg::Vec3(50.0f,750.0f,0.0f));
text->setLayout(osgText::Text::VERTICAL);
text->setText("text->setLayout(osgText::Text::VERTICAL);");
geode->addDrawable(text.get());
}
//-----------------------------------------------//-----------------------------------------------
//设置阴影
{
osg::ref_ptr<osgText::Text> text = new osgText::Text;
text->setFont(font.get());
text->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
text->setCharacterSize(40.0f);
text->setPosition(osg::Vec3(100.0f,650.0f,0.0f));
//设置阴影为DROP_SHADOW_BOTTOM_RIGHT
text->setBackdropType(osgText::Text::DROP_SHADOW_BOTTOM_RIGHT);
text->setBackdropColor(osg::Vec4(0.0f,1.0f,0.0f,1.0f));
text->setBackdropOffset(0.1f,-0.1f);
text->setText("text->setBackdropType(osgText::Text::DROP_SHADOW_BOTTOM_RIGHT);");
geode->addDrawable(text.get());
}
//-----------------------------------------------//-----------------------------------------------
//设置边框
{
osg::ref_ptr<osgText::Text> text = new osgText::Text;
text->setFont(font.get());
text->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
text->setCharacterSize(30.0f);
text->setPosition(osg::Vec3(100.0f,450.0f,0.0f));
//设置边框对齐绘制
text->setDrawMode(osgText::Text::TEXT | osgText::Text::BOUNDINGBOX | osgText::Text::ALIGNMENT);
text->setText("text->setDrawMode(osgText::Text::TEXT | osgText::Text::BOUNDINGBOX | osgText::Text::ALIGNMENT);");
geode->addDrawable(text.get());
}
//-----------------------------------------------//-----------------------------------------------
//设置颜色倾斜模式
{
osg::ref_ptr<osgText::Text> text = new osgText::Text;
text->setFont(font.get());
text->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
text->setCharacterSize(40.0f);
text->setPosition(osg::Vec3(100.0f,250.0f,0.0f));
//设置颜色倾斜模式为PER_CHARACTER
text->setColorGradientMode(osgText::Text::PER_CHARACTER);
//设置倾斜四个角落的颜色
text->setColorGradientCorners(osg::Vec4(1.0f,0.0f,0.0f,1.0f),osg::Vec4(0.0f,1.0f,0.0f,1.0f),
osg::Vec4(0.0f,0.0f,1.0f,1.0f),osg::Vec4(1.0f,1.0f,1.0f,1.0f));
text->setText("text->setColorGradientMode(osgText::Text::SOLID);");
geode->addDrawable(text.get());
}
camera->addChild(geode.get());
return camera.get() ;
}
int main()
{
osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
//创建各种文字效果
osg::ref_ptr<osg::Camera> camera = createAllKindText();
//添加到根节点
osg::ref_ptr<osg::Group> root = new osg::Group() ;
root->addChild(createAllKindText());
//优化场景数据
osgUtil::Optimizer optimizer ;
optimizer.optimize(root.get()) ;
viewer->setSceneData(root.get());
viewer->realize();
viewer->run();:lol
return 0 ;
}
有几点不明白，创建一个相机，是不是必须做如下几点操作：
//设置投影矩阵，设置投影矩阵有什么作用，我也大概知道是三维转二维，但是如果我自己写代码，我不会条件反射的一下子想到加上这行代码
camera->setProjectionMatrix(osg::Matrix::ortho2D(0,1280,0,800));
//设置视图矩阵，设置视图矩阵的作用？
camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
camera->setViewMatrix(osg::Matrix::identity());
//清除深度缓存
camera->setClearMask(GL_DEPTH_BUFFER_BIT);
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