#include "myWin.h"
#include "math.h"
#define ORDER    5 // 次数(dimension)
#define INIT_H  10 // Hの初期値(initial value of H)
#define SX      20 // 画面左上端座標（screen top/left coordinate）
#define RSC      1 // 画面表示倍率の逆数(reverse value of screen scale)

int cX, cY, ID, H;
void pos(int X, int Y){ cX = X; cY = Y;}
int ScXY(int X){ return SX + X/RSC; }
void rLine(HDC hdc, double X, double Y){//相対描画(relatively draw line)
	int nX = cX + X, nY = cY + Y;
	MoveToEx(hdc, ScXY(cX), ScXY(cY), NULL);
	LineTo  (hdc, ScXY(nX), ScXY(nY));
	cX=nX; cY=nY;
}
void URD(HDC hdc);
void LDR(HDC hdc);
void DLU(HDC hdc);
void RUL(HDC hdc){
	if(ID<=0) return;
	ID--; URD(hdc); rLine(hdc, H, 0); RUL(hdc);
	rLine(hdc,  0, H); RUL(hdc); rLine(hdc, -H, 0); DLU(hdc);
    ID++;
}
void DLU(HDC hdc){
	if(ID<=0) return;
	ID--; LDR(hdc); rLine(hdc, 0, -H); DLU(hdc);
	rLine(hdc, -H, 0); DLU(hdc); rLine(hdc,  0, H); RUL(hdc);
    ID++;
}
void LDR(HDC hdc){
	if(ID<=0) return;
	ID--; DLU(hdc); rLine(hdc, -H, 0); LDR(hdc);
	rLine(hdc, 0, -H); LDR(hdc); rLine(hdc, H, 0); URD(hdc);
    ID++;
}
void URD(HDC hdc){
	if(ID<=0) return;
	ID--; RUL(hdc); rLine(hdc, 0, H); URD(hdc);
	rLine(hdc, H, 0); URD(hdc);	rLine(hdc, 0, -H); LDR(hdc);
    ID++;
}
void procPaint(HWND hw, WPARAM wp,LPARAM lp){
	PAINTSTRUCT ps;	HDC hdc=BeginPaint(hw, &ps);
	pos(0,0); ID = ORDER; H = INIT_H; RUL(hdc);
	EndPaint(hw,&ps);
}
void procCreate(HWND hw, WPARAM wp,LPARAM lp){
	SetWindowText(hw,TEXT("Hilbert Curve"));
	MoveWindow(hw,0,0,380,400,TRUE);
}
LRESULT CALLBACK WndProc(HWND hw, UINT msg, WPARAM wp,LPARAM lp){
	switch(msg){
	case WM_DESTROY : PostQuitMessage(0)   ; return 0;
	case WM_CREATE  : procCreate(hw,wp,lp) ; return 0;
	case WM_PAINT   : procPaint(hw,wp,lp)  ; return 0;
	}
	return DefWindowProc(hw,msg,wp,lp);
}