使用OpenGL绘制Bezier曲线_C/C++

使用OpenGL绘制Bezier曲线

2021-09-01 13:54dreamcs C/C++

这篇文章主要为大家详细介绍了使用OpenGL绘制Bezier曲线的方法，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

本文实例为大家分享了OpenGL绘制Bezier曲线的具体代码，供大家参考，具体内容如下

最近在看Francis S Hill ,Jr 和 Stephen M Kelley合著的《计算机图形学》(OpenGL版)(第三版)书中有绘制三个控制点的Bezier曲线的代码。自己重新敲了一遍代码。发现了其中的一点小错误，修正过来了。并做了一点小小的改动。

源码见下

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									#include <windows.h>

									#include <math.h>

									#include <gl/GL.h>

									#include <gl/glut.h>

									int SCREEN_HEIGHT = 480;

									int NUMPOINTS = 0;

									class Point

									{

									public:

									 float x, y;

									 void setxy(float x2, float y2)

									 {

									 x = x2;

									 y = y2;

									 }

									 Point operator&(const Point & rPoint)

									 {

									 x = rPoint.x;

									 y = rPoint.y;

									 return * this;

									 }

									};

									Point abc[3];

									void myInit()

									{

									 glClearColor(0.0,0.0,0.0,0.0);

									 glColor3f(1.0f, 0.0, 0.0);

									 glPointSize(4.0);

									 glMatrixMode(GL_PROJECTION);

									 glLoadIdentity();

									 gluOrtho2D(0.0, 640, 0.0, 480.0);

									}

									void drawDot(Point pt) 

									{

									 glBegin(GL_POINTS);

									 glVertex2f(pt.x, pt.y);

									 glEnd();

									 glFlush();

									}

									void drawLine(Point p1, Point p2)

									{

									 glBegin(GL_LINES);

									 glVertex2f(p1.x, p1.y);

									 glVertex2f(p2.x, p2.y);

									 glEnd();

									 glFlush();

									}

									//三个控制点的贝塞尔曲线

									Point drawBezier(Point A, Point B, Point C, double t) 

									{

									 Point P;

									 P.x = pow((1-t), 2) * A.x + 2*t*(1-t)*B.x + pow(t, 2)*C.x;

									 P.y = pow((1-t), 2) * A.y + 2*t*(1-t)*B.y + pow(t, 2)*C.y;

									 return P;

									}

									void myMouse(int button, int state, int x, int y)

									{

									 if(button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)

									 {

									 abc[NUMPOINTS].setxy((float)x, (float)(SCREEN_HEIGHT - y));

									 NUMPOINTS++;

									 if (NUMPOINTS == 3)

									 {

									  glColor3f(1.0, 0.0, 1.0);

									  drawDot(abc[0]);

									  drawDot(abc[1]);

									  drawDot(abc[2]);

									  glColor3f(1.0, 1.0, 0.0);

									  drawLine(abc[0], abc[1]);

									  drawLine(abc[1], abc[2]);

									  glColor3f(0.0, 1.0, 1.0);

									  Point POld = abc[0];

									  for (double t = 0.0; t<=1.0;t+=0.1)

									  {

									  Point P = drawBezier(abc[0], abc[1], abc[2], t);

									  drawLine(POld, P);

									  POld = P;

									  }

									  glColor3f(1.0, 0.0, 0.0);

									  NUMPOINTS = 0;

									 }

									 }

									}

									void myDisplay()

									{

									 glClear(GL_COLOR_BUFFER_BIT);

									 glFlush();

									}

									int main(int argc, char * agrv[])

									{

									 glutInit(&argc, agrv);

									 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);

									 glutInitWindowSize(640, 480);

									 glutInitWindowPosition(100, 150);

									 glutCreateWindow("Bezier Curve");

									 glutMouseFunc(myMouse);

									 glutDisplayFunc(myDisplay);

									 myInit();

									 glutMainLoop();

									 return 0;

									}