计算机图形学-Bezier曲线算法de-Castljau

/*

1.实现Bezier曲线

2.数据由data.in读入,其格式为:

点数

各个点坐标

例如:

4

10 150

50 50

150 50

190 150

3.可以实现100阶以内Bezier

*/

#include

#include

#include

using namespace std;

LRESULT CALLBACK WinSunProc(

HWND hwnd, // handle to window

UINT uMsg, // message identifier

WPARAM wParam, // first message parameter LPARAM lParam // second message parameter

);

void MidpointLine(int x0, int y0, int x1, int y1, HWND hwnd); void bezier(HWND hwnd);

int cnt = 0;

const int MAX = 105;

const int COUNT = 1000;

int n;

int ptr;

struct Point{

double x, y;

};

vector p[2], vec;

int WINAPI WinMain(

HINSTANCE hInstance, // handle to current instance HINSTANCE hPrevInstance, // handle to previous instance

LPSTR lpCmdLine, // command line

int nCmdShow // show state

)

{

WNDCLASS wndcls;

wndcls.cbClsExtra=0;

wndcls.cbWndExtra=0;

wndcls.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);

wndcls.hCursor=LoadCursor(NULL,IDC_CROSS);

wndcls.hIcon=LoadIcon(NULL,IDI_ERROR);

wndcls.hInstance=hInstance;

wndcls.lpfnWndProc=WinSunProc;

wndcls.lpszClassName="Ted";

wndcls.lpszMenuName=NULL;

wndcls.style=CS_HREDRAW | CS_VREDRAW;

RegisterClass(&wndcls);

HWND hwnd;

hwnd=CreateWindow("Ted","XukeIsDaHaoRen!",WS_OVERLAPPEDWINDOW, 0,0,600,400,NULL,NULL,hInstance,NULL);

ShowWindow(hwnd,SW_SHOWNORMAL);

UpdateWindow(hwnd);

MSG msg;

while(GetMessage(&msg,NULL,0,0))

{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

return 0;

}

LRESULT CALLBACK WinSunProc(

HWND hwnd, // handle to window

UINT uMsg, // message identifier

WPARAM wParam, // first message parameter

LPARAM lParam // second message parameter

)

{

switch(uMsg)

{

case WM_CHAR:

char szChar[20];

sprintf(szChar,"char is %d",wParam);

MessageBox(hwnd,szChar,"Nothing",0);

break;

case WM_LBUTTONDOWN:

MessageBox(hwnd,"Waiting...","Performance",0);

//HDC hdc;

//hdc=GetDC(hwnd);

//MidpointLine(100, 100, 200, 200, hwnd);

bezier(hwnd);

break;

case WM_PAINT:

HDC hDC;

PAINTSTRUCT ps;

hDC=BeginPaint(hwnd,&ps);

TextOut(hDC,0,0,"By Ted",strlen("By Ted"));

EndPaint(hwnd,&ps);

break;

case WM_CLOSE:

if(IDYES==MessageBox(hwnd,"Quit?(Y/N)"," ",MB_YESNO))

{

DestroyWindow(hwnd);

}

break;

case WM_DESTROY:

PostQuitMessage(0);

break;

default:

return DefWindowProc(hwnd,uMsg,wParam,lParam);

}

return 0;

}

int curPtr(){

return ptr % 2;

}

int prePtr(){

return (ptr + 1) % 2;

}

Point cut(Point p1, Point p2, double t){

Point temp;

temp.x = p1.x + t * (p2.x - p1.x);

temp.y = p1.y + t * (p2.y - p1.y);

return temp;

}

Point deCasteljau(double t){

//Point temp;

for(int i = 0; i < n - 1; i++){

int cur = curPtr(), pre = prePtr();

p[pre].clear();

for(int j = 0; j < (int)p[cur].size() - 1; j++){

Point temp = cut(p[cur][j], p[cur][j + 1], t);

p[pre].push_back(temp);

}

++ptr;

}

int cur = curPtr();

return p[cur][0];

}

void bezier(HWND hwnd){

HDC dc;

dc = GetDC(hwnd);

int i;

Point temp;

FILE *fp = fopen("data.in", "r");

fscanf(fp, "%d\n", &n);

//char str[20];

//sprintf(str, "%d\n", n);

//MessageBox(hwnd,"Waiting...",str,0);

for(i = 0; i< n; i++){

fscanf(fp, "%lf %lf\n", &temp.x, &temp.y);

vec.push_back(temp);

}

//HDC dc;

//dc = GetDC(hwnd);

for(i = 0; i < (int)vec.size(); i++){

SetPixel(dc, (int)vec[i].x, (int)vec[i].y, RGB(255,0,0));

if(i < (int)vec.size() - 1){

MoveToEx(dc, (int)vec[i].x, (int)vec[i].y, (LPPOINT) NULL);

//MoveToEx(hdc, (int) 110, (int) 110, (LPPOINT) NULL);

LineTo(dc, (int)vec[i + 1].x, (int)vec[i + 1].y);

}

}

for(int t = 0; t <= COUNT; t++){

ptr = 0;

p[ptr] = vec;

temp = deCasteljau((double)((double)t / (double)COUNT));

SetPixel(dc, (int)temp.x, (int)temp.y, RGB(255,0,0));

}

return ;

}

void MidpointLine(int x0, int y0, int x1, int y1, HWND hwnd)

{

HDC dc;

dc=GetDC(hwnd);

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;

SetPixel(dc,x,y,RGB(255,0,0));

while(x

{

if(d<0)

{

x++;

y++;

d += d2;

}

else

{

x++;

d =+ d1;

}

SetPixel(dc,x,y,RGB(255,0,0));

}

ReleaseDC(hwnd,dc);

}