本文实例为大家分享了QPainter画一个3D正的具体代码，供大家参考，具体内容如下
My3DBox .h
?| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 |
#include <Eigen/Geometry>
using namespace Eigen;
#define SQUARE_LENGTH 200//是一个边长200的正方体
#define CAMERA_DISTANCE 300//视点距离
class My3DBox : public QWidget
{
Q_OBJECT
public:
explicit My3DBox(QWidget *parent = 0);
protected:
QPoint m_mousePos;
Vector3d m_vector[8];//正方形8个点坐标
void mouseMoveEvent(QMouseEvent *);
void paintEvent(QPaintEvent *);
void drawPlane(const QPoint *points,QPainter &painter);
Matrix3d getMartix();
QPoint ToPoint(Vector3d vector);
void drawUp(QPoint *points,QPainter &painter);//正方体面的绘制
void drawDown(QPoint *points,QPainter &painter);
void drawLeft(QPoint *points,QPainter &painter);
void drawRight(QPoint *points,QPainter &painter);
};
|
My3DBox .cpp
?| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 |
#include "widget.h"
#define PI 3.1415926
My3DBox::My3DBox(QWidget *parent) :
QWidget(parent),m_mousePos(0,0)
{
setMouseTracking(true);//在任何情况下启用mouseMoveEvent
setGeometry(400,200,500,500);
m_vector[0] << -100,100,100;//设置正方体顶点初始位置
m_vector[1] << 100,100,100;
m_vector[2] << -100,-100,100;
m_vector[3] << 100,-100,100;
m_vector[4] << -100,100,-100;
m_vector[5] << 100,100,-100;
m_vector[6] << -100,-100,-100;
m_vector[7] << 100,-100,-100;
}
void My3DBox::mouseMoveEvent(QMouseEvent *e)//此处把坐标原点从左上角变换至屏幕中心
{
if(e->pos().x() < 0)
m_mousePos.setX(-width()/2);
else if(e->pos().x() > width())
m_mousePos.setX(width()/2);
else
m_mousePos.setX(e->pos().x() - width()/2);
if(e->pos().y() < 0)
m_mousePos.setY(height()/2);
else if(e->pos().y() > height())
m_mousePos.setY(-height()/2);
else
m_mousePos.setY(-e->pos().y() + height()/2);
update();
}
void My3DBox::paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.setRenderHint(QPainter::SmoothPixmapTransform);
painter.setPen(Qt::NoPen);
painter.fillRect(rect(),QColor(3,22,52));
Vector3d vector[8];
Matrix3d matrix = getMartix();//获取变换矩阵
QPoint points[8];//正面0123 左面4062 右面1537 上面4501 下面 2367(以观察者的方向为主)
for(int i = 0;i < 8;++i)//计算变换后坐标
{
vector[i] = matrix*m_vector[i];
points[i] = ToPoint(vector[i]);
points[i].setX(points[i].x()+width()/2);//将坐标系原点变换至左上角
points[i].setY(-points[i].y()+height()/2);
}
//一共要画5个面，最后画正面
if(qAbs(m_mousePos.x()) > qAbs(m_mousePos.y()))
{
if(m_mousePos.x() > 0)
{
if(m_mousePos.y() > 0)
drawDown(points,painter);
else
drawUp(points,painter);
drawLeft(points,painter);
}
else
{
if(m_mousePos.y() > 0)
drawDown(points,painter);
else
drawUp(points,painter);
drawRight(points,painter);
}
}
else
{
if(m_mousePos.y() > 0)
{
if(m_mousePos.x() > 0)
drawLeft(points,painter);
else
drawRight(points,painter);
drawDown(points,painter);
}
else
{
if(m_mousePos.x() > 0)
drawLeft(points,painter);
else
drawRight(points,painter);
drawUp(points,painter);
}
}
//画正面
QPoint point[4] =
{
points[0],
points[1],
points[3],
points[2]
};
drawPlane(point,painter);
}
void My3DBox::drawPlane(const QPoint *points,QPainter &painter)
{
QLinearGradient linearGradient(points[1],points[3]);//设置渐变色
linearGradient.setColorAt(0.0,QColor(150,150,250));
linearGradient.setColorAt(1.0,QColor(170,170,255));
painter.setBrush(QBrush(linearGradient));
painter.drawConvexPolygon(points,4);
}
Matrix3d My3DBox::getMartix()
{
double unit_x = 0;//同方向单位向量的x和y
double unit_y = 0;
double z = 0;
if(m_mousePos.x() != 0 || m_mousePos.y() != 0)
{
unit_x = m_mousePos.x()/qSqrt(m_mousePos.x()*m_mousePos.x() + m_mousePos.y()*m_mousePos.y());
unit_y = m_mousePos.y()/qSqrt(m_mousePos.x()*m_mousePos.x() + m_mousePos.y()*m_mousePos.y());
z = qSqrt(m_mousePos.x()*m_mousePos.x() + m_mousePos.y()*m_mousePos.y())/qSqrt(width()*width()/4 + height()*height()/4);
}
Matrix3d M_Z;
if(unit_x == 0 && unit_y == 0)
M_Z << 1,0,0,
0,1,0,
0,0,1;
else
M_Z << unit_y,-unit_x,0,
unit_x,unit_y,0,
0,0,1;
Matrix3d M_X;
if(z == 0)
M_X << 1,0,0,
0,1,0,
0,0,1;
else
M_X << 1,0,0,
0,cos(z*PI/2.6),sin(z*PI/2.6),
0,-sin(z*PI/2.6),cos(z*PI/2.6);//为什么PI/2大于90度？因为没画背面所以必须小于90度(偷懒)
return M_Z.inverse()*M_X*M_Z;
}
QPoint My3DBox::ToPoint(Vector3d vector)//将3d坐标投影至平面上
{
QPoint point;
point.setX(CAMERA_DISTANCE*vector[0]/(CAMERA_DISTANCE-vector[2]));
point.setY(CAMERA_DISTANCE*vector[1]/(CAMERA_DISTANCE-vector[2]));
return point;
}
void My3DBox::drawUp(QPoint *points,QPainter &painter)
{
QPoint point[4] =
{
points[4],
points[5],
points[1],
points[0]
};
drawPlane(point,painter);
}
void My3DBox::drawDown(QPoint *points,QPainter &painter)
{
QPoint point[4] =
{
points[2],
points[3],
points[7],
points[6]
};
drawPlane(point,painter);
}
void My3DBox::drawLeft(QPoint *points,QPainter &painter)
{
QPoint point[4] =
{
points[4],
points[0],
points[2],
points[6]
};
drawPlane(point,painter);
}
void My3DBox::drawRight(QPoint *points,QPainter &painter)
{
QPoint point[4] =
{
points[1],
points[5],
points[7],
points[3]
};
drawPlane(point,painter);
}
|
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/BIG_C_GOD/article/details/53285152
如果您对该产品感兴趣，请填写办理（客服微信：xiaoxiongyidong）
发表评论
◎欢迎参与讨论，请在这里发表您的看法、交流您的观点。