計算機圖形學幾個算法的關鍵C++代碼

一、中點畫線算法：

//中點畫線算法
void CMidPointLineView::MyMidLine(int x0, int y0, int x1, int y1)
{
    CClientDC dc(this);

    int a=0;
    int b=0;
    int d1=0;
    int d2=0;
    int d=0;
    int x=0;
    int y=0;

    a=y0-y1;
    b=x1-x0;
    d=2*a+b;
    d1=2*a;
    d2=2*a+2*b;
    x=x0;
    y=y0;

    dc.SetPixel(x,y,RGB(255,0,0));
    while(x<x1)
    {
        if(d<0)
        {
            x++;
            y++;
            d += d2;
        }
        else
        {
            x++;
            d += d1;
        }
        dc.SetPixel(x,y,RGB(255,0,0));
    }
}

二、中點畫圓算法：

//畫1/8圓弧
void CMidPointCircleView::MyMidCircle(int x0,int y0, int r)
{
    CClientDC dc(this);
    int x=0;
    int y=r;
    float d=1.25-r;
    CirclePoint(x0,y0,x,y);
    while(x<=y)
    {
        if(d<0)
        {
           d+=2*x+3;
        }
        else
        {
        d+=2*(x-y)+5;
        y--;
        }
        x++;
        CirclePoint(x0,y0,x,y);
    }
}

三、多邊形裁剪算法：

//直線窗口裁剪
int CPolygonCutView::DrawLine(float x1, float y1, float x2, float y2)

{
    CDC *pDC=GetDC();
    int code1,code2,code;
    float x,y;

    CPen redpen(PS_SOLID,1,RGB(255,0,0));//創建畫實線、線寬為2的紅色畫筆
    CPen *old=pDC->SelectObject(&redpen);

    encode(x1,y1,code1);
    encode(x2,y2,code2);
    while(code1!=0||code2!=0)
    {
        if(code1&code2)
            return 1;//線段在窗口外，返回
        code=code1;
        if(code1==0)code=code2;
        if(l&code)
        {
            x=left;
            y=y1+(y2-y1)*(left-x1)/(x2-x1);
        }
        else if(r&code)
        {
            x=right;
            y=y1+(y2-y1)*(right-x1)/(x2-x1);
        }
        else if(b&code)
        {
            y=bottom;
            x=x1+(x2-x1)*(bottom-y1)/(y2-y1);
        }
        else if(t&code)
        {
            y=top;
            x=x1+(x2-x1)*(top-y1)/(y2-y1);
        }
        if(code==code1)
        {
            x1=x;y1=y;encode(x,y,code1);
        }
        else
        {
            x2=x;y2=y;encode(x,y,code2);
        }
    }
    pDC->MoveTo(x1,y1);
    pDC->LineTo(x2,y2);

    ReleaseDC(pDC);

    return 1;
}

四、多邊形區域填充算法：

//掃描線填充算法
void CFieldFillView::ScanlineSeedfill(CDC *pDC, int x, int y, COLORREF boundaryvalue, COLORREF newvalue)
{
    int x0,xl,xr,y0,xid;
    int flag,xnextspan;
    stack<CPoint> s;//堆棧
    CPoint p;
    s.push(CPoint(x,y));//第一個種子入棧
    while (!s.empty())//堆棧不為空
    {
        p = s.top();
        s.pop();//取棧頂元素并彈棧
        pDC->SetPixel(p.x,p.y,newvalue);//繪制像素點為指定顏色
        x = p.x;y = p.y;
        x0 =x + 1;
        while (pDC->GetPixel(x0,y) != boundaryvalue)//填充右方元素
        {
            pDC->SetPixel(x0,y,newvalue);
            x0++;
        }
        xr = x0 -1;//最右邊像素
        x0 = x -1;
        while (pDC->GetPixel(x0,y) != boundaryvalue)//填充左方像素
        {
            pDC->SetPixel(x0,y,newvalue);
            x0--;
        }
        xl = x0 + 1;//最左邊像素
        //檢查上一條和下一條掃描線，若存在邊界且未填充的像素
        //則選取代表各連續區間的種子像素入棧
        y0 = y;
        for (int i=1;i>=-1;i-=2)
        {
            x0 = xr;
            y = y0 + i;//獲得上一行和下一行
            while (x0 >= xl)
            {
                flag = 0;
                while ((pDC->GetPixel(x0,y) != boundaryvalue)
                    && (pDC->GetPixel(x0,y) != newvalue) 
                    && (x0 > xl))
                {
                    if (flag == 0)
                    {
                        flag = 1;
                        xid = x0;
                    }
                    x0--;
                }
                if (flag == 1)
                {
                    s.push(CPoint(xid,y));//新種子入棧
                    flag = 0;
                }
                xnextspan = x0;
                while ((pDC->GetPixel(x0,y) == boundaryvalue)
                    || (pDC->GetPixel(x0,y) == newvalue)
                    && (x0 >= xl))
                    x0--;
                if (xnextspan == x0) x0--;
            }
        }
    }
}

五、Bezier曲線生成算法：

//畫Bezier曲線
void CBezierView::OnBezier() 
{
    CDC*pDC=GetDC();
    RedrawWindow();
    CPen redpen(PS_SOLID,2,RGB(255,0,0));//創建畫筆
    CPen *old=pDC->SelectObject(&redpen);
    float x0=50,y0=80,x1=150,y1=250,x2=400,y2=130,x3=300,y3=70;
    float x,y,dt,t,n=30.0;
    int i ;
    dt=1/n;
    for(i=0;i<=n;i++)
    {
        t=i*dt;
        x=x0*(1-t)*(1-t)*(1-t)+x1*3*t*(1-t)*(1-t)+x2*3*t*t*(1-t)+x3*t*t*t;
        y=y0*(1-t)*(1-t)*(1-t)+y1*3*t*(1-t)*(1-t)+y2*3*t*t*(1-t)+y3*t*t*t;
        if(i==0)pDC->MoveTo(x,y);
        pDC->LineTo(x,y);
    }
    pDC->MoveTo(x0,y0);
    pDC->LineTo(x1,y1);
    pDC->LineTo(x2,y2);
    pDC->LineTo(x3,y3);

    pDC->SelectObject(old);
    ReleaseDC(pDC);
}

工程文件下載地址：http://www.kuaipan.cn/file/id_8128290032206914.htm