计算机图形学 实现b样条

#include<graphics.h>/*加入c图形库*/ #include<conio.h>/*键盘控制*/ #include<stdlib.h> #include<stdio.h> float px[10]={50,90,150,120,220,300,380,320,450,500}; float py[10]={100,60,50,150,240,100,100,200,250,130};/*控制点*/ void B_spline() { float a0,a1,a2,a3,b0,b1,b2,b3; int k,x,y; float i,t,dt,n=10; setcolor(WHITE); dt=1/n; for(k=0;k<10;k++) { if(k==0) moveto(px[k],py[k]); lineto(px[k],py[k]); }/*特征多边形*/ setcolor(RED); for(k=0;k<7;k++) { if(getch()==17)exit(1);/*读入键盘按键*/ a0=(px[k]+4*px[k+1]+px[k+2])/6; a1=(px[k+2]-px[k])/2; a2=(px[k]-2*px[k+1]+px[k+2])/2; a3=-(px[k]-3*px[k+1]+3*px[k+2]-px[k+3])/6; b0=(py[k]+4*py[k+1]+py[k+2])/6; b1=(py[k+2]-py[k])/2; b2=(py[k]-2*py[k+1]+py[k+2])/2; b3=-(py[k]-3*py[k+1]+3*py[k+2]-py[k+3])/6; for(i=0;i<n;i+=0.1) { t=i*dt; x=a0+a1*t+a2*t*t+a3*t*t*t; y=b0+b1*t+b2*t*t+b3*t*t*t; if(i==0) moveto(x,y); lineto(x,y); } } } void main() { int driver,mode; int gdriver=DETECT,gmode; driver=DETECT;/*初始化显示模式参数*/ initgraph(&gdriver,&gmode,"d:\\tc");/*初始化显示为默认的640*480、16色模式*/ printf("Press any key to continue except 'Ctrl+Q' to quit.\n"); B_spline(); if(getch()==17)exit(1);/*读入键盘按键*/ closegraph();/*关闭图形模式*/ }