两点三次Hermiter插值C++代码

末蓝、 2021-11-05 03:01 314阅读 0赞

#include <math.h>
    #include <gl/glut.h>
    #include <iostream>
    using namespace std;
    
    struct  Point2
    {
        double x;
        double y;
    
        Point2(int px, int py) { x = px; y = py; }
    };
    
    Point2 P0(100, 200);
    Point2 P1(350, 200);
    Point2 derP0(200, 200);
    Point2 derP1(200, 200);
    
    bool mouseLeftDown = false;
    bool mouseRightDown = false;
    
    /*计算Hermite曲线*/
    void Hermit(int n)
    {
        float f1, f2, f3, f4;
    
        double deltaT = 1.0 / n;
    
        glBegin(GL_LINE_STRIP);
        for (int i = 0; i <= n; i++) {
    
            double T = i * deltaT;
    
            f1 = 2.0*pow(T, 3) - 3.0*pow(T, 2) + 1.0;
            f2 = -2.0*pow(T, 3) + 3.0*pow(T, 2);
            f3 = pow(T, 3) - 2.0*pow(T, 2) + T;
            f4 = pow(T, 3) - pow(T, 2);
    
            glVertex2f(f1*P0.x + f2*P1.x + f3*derP0.x + f4*derP1.x,
                f1*P0.y + f2*P1.y + f3*derP0.y + f4*derP1.y);
        }
        glEnd();
    }
    
    /*用鼠标进行绘制，完成后可改变控制点，拖动即可*/
    void display() {
        glClear(GL_COLOR_BUFFER_BIT);
    
        glLineWidth(1.5);
        glColor3f(1.0, 0.0, 0.0);
        glBegin(GL_LINES);
        glVertex2f(P0.x, P0.y);
        glVertex2f(P0.x + derP0.x / 4, P0.y + derP0.y / 4);
        glVertex2f(P1.x, P1.y);
        glVertex2f(P1.x - derP1.x / 4, P1.y - derP1.y / 4);
        glEnd();
    
        glColor3f(0.0, 0.0, 1.0);
        glPointSize(10.0f);
    
        glBegin(GL_POINTS);
        glVertex2f(P0.x, P0.y);
        glVertex2f(P0.x + derP0.x / 4, P0.y + derP0.y / 4);
        glVertex2f(P1.x, P1.y);
        glVertex2f(P1.x - derP1.x / 4, P1.y - derP1.y / 4);
        glEnd();
    
        Hermit(20);
    
        glFlush();
        glutSwapBuffers();
    }
    
    void init()
    {
        glClearColor(1.0, 1.0, 1.0, 0.0);
        glShadeModel(GL_FLAT);
    }
    
    void myReshape(int w, int h)
    {
        glViewport(0, 0, (GLsizei)w, (GLsizei)h);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluOrtho2D(0.0, (GLsizei)w, (GLsizei)h, 0.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
    }
    
    void mouse(int button, int state, int x, int y)
    {
        if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
        {
            mouseLeftDown = true;
        }
    
        if (button == GLUT_LEFT_BUTTON && state == GLUT_UP)
        {
            mouseLeftDown = false;
        }
    
        if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
        {
            mouseRightDown = true;
        }
    
        if (button == GLUT_RIGHT_BUTTON && state == GLUT_UP)
        {
            mouseRightDown = false;
        }
    }
    
    double distance(int x1, int y1, int x2, int y2)
    {
        return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
    }
    
    void motion(int x, int y)
    {
        if (mouseLeftDown)
        {
            if (distance(P0.x + derP0.x / 4, P0.y + derP0.y / 4, x, y) < 20)
            {
                derP0.x = (x - P0.x) * 4;
                derP0.y = (y - P0.y) * 4;
            }
    
            if (distance(P1.x - derP1.x / 4, P1.y - derP1.y / 4, x, y) < 20)
            {
                derP1.x = (P1.x - x) * 4;
                derP1.y = (P1.y - y) * 4;
            }
        }
    
        glutPostRedisplay();
    }
    
    int  main(int argc, char** argv)
    {
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
        glutInitWindowSize(450, 450);
        glutInitWindowPosition(200, 200);
        glutCreateWindow("hello");
        init();
    
        glutDisplayFunc(display);
        glutReshapeFunc(myReshape);
        glutMouseFunc(mouse);
        glutMotionFunc(motion);
    
        glutMainLoop();
        return 0;
    }

转载于:https://www.cnblogs.com/yibeimingyue/p/11178141.html