BOOL groundClip(){

	static struct {
		double x,y;
	}vX,vY; // 視野ベクトル

	static double r = 0.0; // 見ている方向(テスト用)

	HDC hdc; D3Z.lpBackBuffer->GetDC(&hdc;); // デバイスコンテキスト取得

	// ブラシなどを初期化

	HBRUSH hRedBrush,hGreenBrush,oldBrush,hBlueBrush;
	hRedBrush = CreateSolidBrush(RGB(255,80,80));
	hGreenBrush = CreateSolidBrush(RGB(80,255,80));
	hBlueBrush = CreateSolidBrush(RGB(80,80,255));
	oldBrush = SelectObject(hdc,hRedBrush);


	// キーボード読み取り
	char key[256];

	GetKeyboardState((unsigned char*)key);

	if( key[VK_LEFT]  &0xf0) r -= 10.0;
	if( key[VK_RIGHT] &0xf0) r += 10.0;
	if( key[VK_ESCAPE] &0xf0) 	DestroyWindow(hwnd);


	// テスト用に視野ベクトルを算出
	double rad = r*3.14159/180;

	vX.x = cos(rad);
	vX.y = sin(rad);

	vY.x = -sin(rad);
	vY.y = cos(rad);

	static double ax = 5.0,ay = 5.0;

	// 視点の移動
	if( key[VK_UP]&0xf0  ) {

		ax += (vX.x + vY.x)/2;
		ay += (vX.y + vY.y)/2;

	}
	if( key[VK_DOWN]&0xf0  ) {

		ax -= (vX.x + vY.x)/2;
		ay -= (vX.y + vY.y)/2;

	}

	mx = ax;
	my = ay;

	int div;
	if( vX.x > 0 ){
		if(vX.y > 0){
			if(vY.y>0){
				div = 0;
			}else{
				div = 1;
			}
		}else{
			if(vY.y>0){
				div = 1;
			}else{
				div = 2;
			}
		}
	}else{
		if(vX.y > 0){
			if(vY.y > 0){
				div = 0;
			}else{
				div = 3;
			}
		}else{
			if(vY.y > 0){
				div = 3;
			}else{
				div = 2;
			}
		}
	}
	
	int x1,y1,x2,y2;
	switch(div){
		case 0:
			x1 = mx - VIEWWIDTH/2;
			y1 = my ;//- VIEWHEIGHT/2;
			x2 = mx + VIEWWIDTH/2;
			y2 = my + VIEWHEIGHT/2;
			break;
		case 1:
			x1 = mx;
			y1 = my - VIEWHEIGHT/2;
			x2 = mx + VIEWWIDTH/2;
			y2 = my + VIEWHEIGHT/2 ;
			break;
		case 2:
			x1 = mx - VIEWWIDTH/2;
			y1 = my - VIEWHEIGHT/2;
			x2 = mx + VIEWWIDTH/2;
			y2 = my +1;
			break;
		case 3:
			x1 = mx - VIEWWIDTH/2;
			y1 = my - VIEWHEIGHT/2;
			x2 = mx +1;
			y2 = my + VIEWHEIGHT/2;
			break;
	}


	int i,j;
	for(j= y1 ;j < y2;j++)
		for(i =x1;i < x2;i++){
		
		// 点を表示
		
		RECT rect;

		int x = i*10;
		int y = j*10;

		rect .left  = x;
		rect .top   = y;
		rect .right = x+5;
		rect .bottom= y+5;



		FillRect(hdc,▭,hRedBrush);

		if( (i-mx)*vX.y < (j-my)*vX.x )
		if( (i-mx)*vY.y > (j-my)*vY.x ){
			// 見える範囲
			FillRect(hdc,▭,hGreenBrush);
		}

		if( ( i == mx ) && (j==my)){
			// 視点の位置

			FillRect(hdc,▭,hBlueBrush);

			// 視野ベクトル
			HPEN hPen = CreatePen(PS_SOLID, 1, RGB(255,255,255)),oldPen;

			oldPen = SelectObject(hdc,hPen);

			POINT currentPos;
			MoveToEx(hdc, x,y ,¤tPos;);
			LineTo(hdc, x + (vX.x*10) , y + (vX.y*10) );

			HPEN hPen2 = CreatePen(PS_SOLID, 1, RGB(255,255,000));

			SelectObject(hdc,hPen2);
			
			MoveToEx(hdc, x,y ,¤tPos;);
			LineTo(hdc, x + (vY.x*10) , y + (vY.y*10) );

			SelectObject(hdc,oldPen);
			DeleteObject(hPen2);
			DeleteObject(hPen);
		}

	
	}

	SelectObject(hdc,oldBrush);
	DeleteObject(hRedBrush);
	DeleteObject(hBlueBrush);
	DeleteObject(hGreenBrush);


	D3Z.lpBackBuffer->ReleaseDC(hdc);

	return TRUE;
}