公司网站开发策划,深圳东门市场,自己做网站 有名6,模仿网站页面违法吗目录
1. 前言
2. 预备知识
3. Qt实现的二维Cardinal曲线
4. 用osg实现三维Cardinal曲线 4.1. 工具/ 原料 4.2. 代码实现 1. 前言 在设计矢量图案的时候#xff0c;我们常常需要用到曲线来表达物体造型#xff0c;单纯用鼠标轨迹绘制显然是不足的。于是我们希望能够实现这…目录
1. 前言
2. 预备知识
3. Qt实现的二维Cardinal曲线
4. 用osg实现三维Cardinal曲线 4.1. 工具/ 原料 4.2. 代码实现 1. 前言 在设计矢量图案的时候我们常常需要用到曲线来表达物体造型单纯用鼠标轨迹绘制显然是不足的。于是我们希望能够实现这样的方法通过设计师手工选择控制点再通过插值得到过控制点或在附近的一条平滑曲线。在这样的需求下样条曲线诞生了。简而言之样条曲线是由多个多项式按比例系数组成的多项式函数而比例系数是由控制点决定的。Hermite曲线、Cardinal曲线在平时的开发中经常用于模拟运动物体的轨迹如下 以上是二维下的Cardinal曲线效果如何用osg实现 三维的Cardinal曲线呢即像下面那样 即
单击“拾取点”按钮该按钮文字变为“关闭拾取点”此时可以用鼠标在棋盘格上单击点击的点用红色圆圈表示。当所有的点都拾取完单击“绘制”可以绘制三维Cardinal曲线。当绘制完三维Cardinal曲线后再次用鼠标在棋盘格上单击单击“绘制”可以绘制新的三维Cardinal曲线。单击“关闭拾取点”按钮鼠标在棋盘格上单击时无法拾取点。调整阈值可以更改曲线的圆弧度使曲线从圆滑变为直线。
2. 预备知识 关于Hermite曲线、Cardinal曲线的数学理论参见如下博文
[计算机动画] 路径曲线与运动物体控制Cardinal样条曲线。三次参数样条曲线与Cardinal曲线。
3. Qt实现的二维Cardinal曲线 如下博文为Qt实现的二维Cardinal曲线
Qt实现三次样条Cardinal曲线
4. 用osg实现三维Cardinal曲线 4.1. 工具/ 原料
开发环境如下
Qt 5.14.1。Visual Studio 2022。OpenSceneGraph 3.6.2。 4.2. 代码实现
main.cpp
#include osgCardinal.h
#include QtWidgets/QApplicationint main(int argc, char *argv[])
{QApplication a(argc, argv);osgCardinal w;w.show();return a.exec();
}myEventHandler.cpp
#include myEventHandler.h
#includeosgViewer/Viewer
bool myEventHandler::handle(const osgGA::GUIEventAdapter ea, osgGA::GUIActionAdapter aa, osg::Object* obj, osg::NodeVisitor* nv)
{auto pViewer dynamic_castosgViewer::Viewer*(aa);auto eventType ea.getEventType();switch (eventType){case GUIEventAdapter::PUSH:{if(_bPickPoint (GUIEventAdapter::LEFT_MOUSE_BUTTON ea.getButton())){osgUtil::LineSegmentIntersector::Intersections intersections;auto bRet pViewer-computeIntersections(ea, intersections);if (!bRet) // 判断是否相交{return false;}auto iter intersections.begin(); // 取相交的第1个点auto interPointCoord iter-getLocalIntersectPoint();_pOsgCardinal-drawEllipse(interPointCoord);}}break;} // end switchreturn false;
}void myEventHandler::setPickPoint(bool bPickPoint)
{_bPickPoint bPickPoint;
}myEventHandler.h
#ifndef MYEVENTHANDLER_H
#define MYEVENTHANDLER_H
#includeosgGA/GUIEventHandler
#includeosgCardinal.h
using namespace osgGA;class myEventHandler:public GUIEventHandler
{
public:myEventHandler(osgCardinal* p) { _pOsgCardinal p; }
public:void setPickPoint(bool bPickPoint);private:virtual bool handle(const osgGA::GUIEventAdapter ea, osgGA::GUIActionAdapter aa, osg::Object* obj, osg::NodeVisitor* nv) override;private:bool _bPickPoint{false};osgCardinal* _pOsgCardinal{nullptr};
};#endif MYEVENTHANDLER_H
osgCardinal.h
#pragma once#include QtWidgets/QWidget
#include ui_osgCardinal.h
using std::list;QT_BEGIN_NAMESPACE
namespace Ui { class osgCardinalClass; };
QT_END_NAMESPACEclass myEventHandler;class osgCardinal : public QWidget
{Q_OBJECTpublic:osgCardinal(QWidget *parent nullptr);~osgCardinal();public:// 画点。以小圆表示void drawEllipse(const osg::Vec3d pt);private:void addBaseScene();osg::Geode* createGrid();void valueChanged(double dfValue);void startDraw();void pickPoint();void clear();// 计算MC矩阵void calMcMatrix(double s);// 压入头部和尾部两个点用于计算void pushHeadAndTailPoint();// 画Cardinal曲线void drawCardinal();void drawLines(osg::Vec3Array* pVertArray);
private:Ui::osgCardinalClass *ui;myEventHandler*_myEventHandler{nullptr};bool _startPickPoint{false};bool _lastPointHasPoped{ false }; // 最后一个点是否被弹出删除bool _hasDrawed{ false }; // 以前是否绘制过Cardinal曲线double _dfMcMatrix[4][4];listosg::Vec3d _lstInterPoint;osg::Vec3Array*_pVertArray{ nullptr };osg::Geometry* _pCardinalCurveGemo{ nullptr };
};osgCardinal.cpp
#include osgCardinal.h
#includemyEventHandler.h
#includeosg/MatrixTransform
#includeosg/PositionAttitudeTransform
#includeosg/PolygonMode
#includeosg/LineWidth
#includevector
using std::vector;osgCardinal::osgCardinal(QWidget *parent): QWidget(parent), ui(new Ui::osgCardinalClass())
{ui-setupUi(this);setWindowState(Qt::WindowMaximized);addBaseScene();ui-doubleSpinBox-setMinimum(0);ui-doubleSpinBox-setMaximum(1);ui-doubleSpinBox-setValue(0.5);ui-doubleSpinBox-setSingleStep(0.1);connect(ui-doubleSpinBox, QOverloaddouble::of(QDoubleSpinBox::valueChanged), this, osgCardinal::valueChanged);connect(ui-startDrawBtn, QAbstractButton::clicked, this, osgCardinal::startDraw);connect(ui-clearBtn, QAbstractButton::clicked, this, osgCardinal::clear);connect(ui-pickPointBtn, QAbstractButton::clicked, this, osgCardinal::pickPoint);calMcMatrix(0.5);
}osgCardinal::~osgCardinal()
{delete ui;
}void osgCardinal::valueChanged(double dfValue)
{auto s (1 - dfValue) / 2.0;// 计算MC矩阵calMcMatrix(s);drawCardinal();
}// 画点。以小圆表示
void osgCardinal::drawEllipse(const osg::Vec3d pt)
{if (!_lastPointHasPoped _hasDrawed !_lstInterPoint.empty()){_lstInterPoint.pop_back();_lastPointHasPoped true;}_lstInterPoint.emplace_back(pt);auto pGeometry new osg::Geometry;auto pVertArray new osg::Vec3Array;auto radius 0.2;auto twoPi 2 * 3.1415926;for (auto iAngle 0.0; iAngle twoPi; iAngle 0.001){auto x pt.x() radius * std::cosf(iAngle);auto y pt.y() radius * std::sinf(iAngle);auto z pt.z() 0.001; // 注意适当增加点否则和网格重合了会导致圆形绘制不正常pVertArray-push_back(osg::Vec3d(x, y, z));}pGeometry-setVertexArray(pVertArray);auto pColorArray new osg::Vec4Array;pColorArray-push_back(osg::Vec4d(1.0, 0.0, 0.0, 1.0));pGeometry-setColorArray(pColorArray/*, osg::Array::BIND_OVERALL*/);pGeometry-setColorBinding(osg::Geometry::BIND_OVERALL);pGeometry-addPrimitiveSet(new osg::DrawArrays(GL_POLYGON, 0, pVertArray-size()));auto pMatrixTransform ui-osg_widget-getSceneData()-asGroup()-getChild(0)-asTransform()-asMatrixTransform();pMatrixTransform-addChild(pGeometry);
}void osgCardinal::pickPoint()
{_startPickPoint !_startPickPoint;_myEventHandler-setPickPoint(_startPickPoint);if (_startPickPoint){ui-pickPointBtn-setText(QString::fromLocal8Bit(关闭拾取点));}else{ui-pickPointBtn-setText(QString::fromLocal8Bit(拾取点));}
}void osgCardinal::startDraw()
{if (nullptr ! _pCardinalCurveGemo) // 如果以前绘制过Cardinal曲线{/* 在上次绘制Cardinal曲线时通过pushHeadAndTailPoint()* 压入的头部、尾部用户控制的两个点去掉以重新压入头部、尾部用户控制的两个点* ,便于绘制本次曲线*/if (_lstInterPoint.size() 0 ) {_lstInterPoint.pop_front();}}pushHeadAndTailPoint();drawCardinal();_hasDrawed true;
}// 压入头部和尾部两个点用于计算
void osgCardinal::pushHeadAndTailPoint()
{// 随便构造两个点auto ptBegin _lstInterPoint.begin();auto x ptBegin-x() 20;auto y ptBegin-y() 20;auto z ptBegin-z();_lstInterPoint.insert(_lstInterPoint.begin(), osg::Vec3d(x, y, z));auto ptEnd _lstInterPoint.back();x ptEnd.x() 20;y ptEnd.y() 20;z ptBegin-z();_lstInterPoint.insert(_lstInterPoint.end(), osg::Vec3d(x, y, z));
}// 画Cardinal曲线
void osgCardinal::drawCardinal()
{if (_lstInterPoint.size() 4){return;}if (nullptr _pVertArray){_pVertArray new osg::Vec3Array();}else{_pVertArray-clear();}auto iter _lstInterPoint.begin();iter; // 第1个点基于0的索引_pVertArray-push_back(*iter);--iter;auto endIter _lstInterPoint.end();int nIndex 0;while (true){--endIter;nIndex;if (3 nIndex){break;}}for (; iter ! endIter; iter){auto p0 *iter;auto p1 *(iter);auto p2 *(iter);auto p3 *(iter);--iter;--iter;--iter;vectorosg::Vec3dvtTempPoint;vtTempPoint.push_back(p0);vtTempPoint.push_back(p1);vtTempPoint.push_back(p2);vtTempPoint.push_back(p3);for (auto i 0; i 4; i){vtTempPoint[i] p0 * _dfMcMatrix[i][0] p1 * _dfMcMatrix[i][1] p2 * _dfMcMatrix[i][2] p3 * _dfMcMatrix[i][3];}float t3, t2, t1, t0;for (double t 0.0; t 1; t 0.01){t3 t * t * t; t2 t * t; t1 t; t0 1;osg::Vec3d newPoint;newPoint vtTempPoint[0] * t3 vtTempPoint[1] * t2 vtTempPoint[2] * t1 vtTempPoint[3] * t0;_pVertArray-push_back(newPoint);}}drawLines(_pVertArray);
}void osgCardinal::drawLines(osg::Vec3Array* pVertArray)
{if (nullptr _pCardinalCurveGemo){_pCardinalCurveGemo new osg::Geometry;auto pLineWidth new osg::LineWidth(50);_pCardinalCurveGemo-getOrCreateStateSet()-setAttributeAndModes(pLineWidth);auto pColorArray new osg::Vec4Array;pColorArray-push_back(osg::Vec4d(0.0, 1.0, 0.0, 1.0));_pCardinalCurveGemo-setColorArray(pColorArray/*, osg::Array::BIND_OVERALL*/);_pCardinalCurveGemo-setColorBinding(osg::Geometry::BIND_OVERALL);auto pMatrixTransform ui-osg_widget-getSceneData()-asGroup()-getChild(0)-asTransform()-asMatrixTransform();pMatrixTransform-addChild(_pCardinalCurveGemo);}// 曲线可能变了先删除上次的曲线_pCardinalCurveGemo-removePrimitiveSet(0);_pCardinalCurveGemo-setVertexArray(pVertArray);// 再用新点绘制新曲线_pCardinalCurveGemo-addPrimitiveSet(new osg::DrawArrays(GL_LINE_STRIP, 0, pVertArray-size()));
}// 计算MC矩阵
void osgCardinal::calMcMatrix(double s)
{_dfMcMatrix[0][0] -s, _dfMcMatrix[0][1] 2 - s, _dfMcMatrix[0][2] s - 2, _dfMcMatrix[0][3] s;_dfMcMatrix[1][0] 2 * s, _dfMcMatrix[1][1] s - 3, _dfMcMatrix[1][2] 3 - 2 * s, _dfMcMatrix[1][3] -s;_dfMcMatrix[2][0] -s, _dfMcMatrix[2][1] 0, _dfMcMatrix[2][2] s, _dfMcMatrix[2][3] 0;_dfMcMatrix[3][0] 0, _dfMcMatrix[3][1] 1, _dfMcMatrix[3][2] 0, _dfMcMatrix[3][3] 0;
}void osgCardinal::clear()
{_lstInterPoint.clear();_hasDrawed false;_lastPointHasPoped false;
}osg::Geode* osgCardinal::createGrid()
{auto pGeode new osg::Geode;auto pVertArray new osg::Vec3Array;for (auto y -10; y 10; y){for (auto x -10; x 10; x){pVertArray-push_back(osg::Vec3d(x, y, 0.0));pVertArray-push_back(osg::Vec3d(x 1, y, 0.0));pVertArray-push_back(osg::Vec3d(x 1, y 1, 0.0));pVertArray-push_back(osg::Vec3d(x, y 1, 0.0));}}auto iSize pVertArray-size();osg::DrawElementsUShort* pEle{ nullptr };osg::Geometry* pGeomerty{ nullptr };osg::Vec4Array* pColorArray{ nullptr };auto nQuardIndex 0;bool bNewLineQuard true; // 新的一行四边形for (auto iVertIndex 0; iVertIndex iSize; iVertIndex){if (0 (iVertIndex % 4)){pEle new osg::DrawElementsUShort(GL_QUADS);pGeomerty new osg::Geometry;pGeomerty-getOrCreateStateSet()-setMode(GL_LIGHTING, osg::StateAttribute::OFF);pGeomerty-addPrimitiveSet(pEle);pGeode-addDrawable(pGeomerty);pGeomerty-setVertexArray(pVertArray);pColorArray new osg::Vec4Array();if (bNewLineQuard){pColorArray-push_back(osg::Vec4d(1.0, 1.0, 1.0, 1.0));}else{pColorArray-push_back(osg::Vec4d(0.0, 0.0, 0.0, 1.0));}nQuardIndex;if (0 ! (nQuardIndex % 20)){bNewLineQuard !bNewLineQuard;}pGeomerty-setColorArray(pColorArray, osg::Array::Binding::BIND_PER_PRIMITIVE_SET);}pEle-push_back(iVertIndex);} // end forreturn pGeode;
}void osgCardinal::addBaseScene()
{auto pAxis osgDB::readRefNodeFile(R(E:\osg\OpenSceneGraph-Data\axes.osgt));if (nullptr pAxis){OSG_WARN axes node is nullpr!;return;}auto pRoot new osg::Group();pRoot-getOrCreateStateSet()-setMode(GL_LIGHTING, osg::StateAttribute::OFF);auto pMatrixRoot new osg::MatrixTransform;auto pGrid createGrid();pMatrixRoot-addChild(pGrid);pMatrixRoot-addChild(pAxis);pRoot-addChild(pMatrixRoot);pMatrixRoot-setMatrix(osg::Matrix::rotate(osg::inDegrees(60.0), osg::Vec3(1, 0, 0)));ui-osg_widget-setSceneData(pRoot);ui-osg_widget-setCameraManipulator(new osgGA::TrackballManipulator);ui-osg_widget-addEventHandler(new osgViewer::WindowSizeHandler);ui-osg_widget-addEventHandler(new osgViewer::StatsHandler);_myEventHandler new myEventHandler(this);ui-osg_widget-addEventHandler(_myEventHandler);// 模拟鼠标滚轮朝向人滚动三次以便场景离人显得更近些for (auto iLoop 0; iLoop 3; iLoop){ui-osg_widget-getEventQueue()-mouseScroll(osgGA::GUIEventAdapter::SCROLL_DOWN);}
}
QtOsgView.h、QtOsgView.cpp文件参见osg嵌入到Qt窗体实现Qt和osg混合编程 博文。
