随机L系统分形树 分类： 计算机图形学 2014-06-01 23:27 376人阅读 评论(0) 收藏

下面代码需要插入到MFC项目中运行，实现了计算机图形学中的L系统分形树。

class  Node
{
public:
int x,y;
double direction;
Node(){}
};

CString   way[3] ;//提供三种生成规则
CString   rule,temprule;
int   len ; //单步长
int	  angle; //旋转转角度
int	  degree ; //迭代次数
int	   x,y ; //原点坐标
Node   stack[1024];
int		stackpointer;
CTest18View::CTest18View()
{
way[0] =   "F[+F]F[-F]F";
way[1] =  "F[+F]F[-F[+F]]";
way[2] =  "FF-[-F+F+F]+[+F-F-F]";
len =3 ;
angle = 30 ;
degree =5;
x = 400 ;
y = 500 ;
stackpointer = 0 ;
for (int i = 0 ; i <1024 ; i++ )
{
stack[i].x =  0 ;
stack[i].direction = NULL ;
}
rule  = way[rand() % 3] ;
for ( int i=1;i<= degree;i++)
{
int curlen = temprule.GetLength ();
int pos=0 , j = 0 ;
while (j < curlen)
{
if(temprule[j] == 'F' )
{
rule += way[rand()%3 ];
j++;
pos = rule.GetLength()-1 ;
}
else
{
rule += temprule[j] ;
pos ++;
j++;
}
}
temprule = rule ;
rule.Empty();
}
rule = temprule ;
}

void CTest18View::OnDraw(CDC* pDC)
{
CTest18Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
if (!pDoc)
return;
CPen pen(PS_SOLID,1,RGB(0,0,255));
pDC->SelectObject(pen);
Node  Nextnode ,Curnode;
Curnode.x = x ;
Curnode.y = y ;
Curnode.direction = 90 ;
int length =rule.GetLength ();
int  i = 0;
pDC ->MoveTo (x,y);
while (i<length)
{
switch(rule[i])
{
case 'F':
Nextnode.x = Curnode.x  + len * cos(Curnode.direction * PI /180);
Nextnode.y = Curnode.y  - len * sin(Curnode.direction * PI /180);
Nextnode.direction =Curnode.direction ;
pDC ->LineTo (Nextnode.x,Nextnode.y);
Curnode = Nextnode;
break ;
case '[':
stack[stackpointer] = Curnode;
stackpointer ++;
break;
case ']':
Curnode = stack[stackpointer-1];
stackpointer -- ;
pDC ->MoveTo (Curnode.x,Curnode.y);
break;
case '+':
Curnode.direction = Curnode.direction + angle;
break;
case '-':
Curnode.direction = Curnode.direction -angle;
break;
default:
;
}
i++;
}
}