//
//        加算による和音作成
//
//   2001/ 6/21,2001/ 9/11 宍戸　輝光
//

#include <windows.h>
#include <math.h>

HINSTANCE hInst;

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);

HWND hwMain;

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,
                    PSTR szCmdLine,int iCmdShow){

	MSG  msg;
	WNDCLASSEX wndclass;

	// ウインドウクラス設定
	wndclass.cbSize        = sizeof(wndclass);
	wndclass.style         = CS_HREDRAW | CS_VREDRAW;
	wndclass.lpfnWndProc   = WndProc;
	wndclass.cbClsExtra    = 0;
	wndclass.cbWndExtra    = 0;
	wndclass.hInstance     = hInstance;
	wndclass.hIcon         = LoadIcon(NULL,IDI_APPLICATION);
	wndclass.hCursor       = LoadCursor(NULL,IDC_ARROW);
	wndclass.hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH);
	wndclass.lpszMenuName  = NULL;
	wndclass.lpszClassName = "CWindow";
	wndclass.hIconSm       = NULL;

	RegisterClassEx(&wndclass); /* ウインドウクラス登録 */

	hwMain = CreateWindow("CWindow","和音演奏",
	  WS_OVERLAPPEDWINDOW | WS_VISIBLE,CW_USEDEFAULT,CW_USEDEFAULT,
	  280,120,NULL,NULL,hInstance,NULL);

	while (GetMessage(&msg,NULL,0,0)) { /* メッセージループ */

		TranslateMessage(&msg);
		DispatchMessage(&msg);

	}

	return msg.wParam;

}

LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam) {

	static short int lpBuf[24000];
	static HWAVEOUT hWOut;
	static WAVEHDR wh;
	static WAVEFORMATEX wf;
	int i,l;
	static double lfRate,lfFreq[3];

	switch (iMsg) {

	case WM_CREATE:

		/* 半音一つの倍率 */
		lfRate=pow(2,1.0/12.0);

		/* オクターブ４のド、ミ、ソの周波数 */
		lfFreq[0]=220*pow(lfRate,3);
		lfFreq[1]=lfFreq[0]*pow(lfRate,4);
		lfFreq[2]=lfFreq[1]*pow(lfRate,3);

		/* ドの音の波長計算 */
		l=(int)(8000.0/lfFreq[0]);

		for (i=0;i<24000;i++) { /* ドの音の波形生成 */

			if ((i % l)<l/2)
				lpBuf[i]=8000;
			else
				lpBuf[i]=-8000;

		}

		/* ミの音の波長計算 */
		l=(int)(8000.0/lfFreq[1]);

		for (i=8000;i<24000;i++) { /* ミの音を重ねる */

			if ((i % l)<l/2)
				lpBuf[i]+=8000;
			else
				lpBuf[i]-=8000;

		}

		/* ソの音の波長計算 */
		l=(int)(8000.0/lfFreq[2]);

		for (i=16000;i<24000;i++) { /* ソの音を重ねる */

			if ((i % l)<l/2)
				lpBuf[i]+=8000;
			else
				lpBuf[i]-=8000;

		}

		wf.wFormatTag=WAVE_FORMAT_PCM;
		wf.nChannels=1;
		wf.nSamplesPerSec=8000;
		wf.nAvgBytesPerSec=16000;
		wf.nBlockAlign=1;
		wf.wBitsPerSample=16;
		wf.cbSize=0;

		/* デバイスオープン */
		waveOutOpen(&hWOut,WAVE_MAPPER,&wf,(DWORD)hwnd,0,CALLBACK_WINDOW);

		wh.lpData=(char *)lpBuf;
		wh.dwBufferLength=48000;
		wh.dwBytesRecorded=0;
		wh.dwUser=0;
		wh.dwFlags=0;
		wh.dwLoops=1;
		wh.lpNext=NULL ;
		wh.reserved=0 ;

		waveOutPrepareHeader(hWOut,&wh,sizeof(WAVEHDR));
		waveOutWrite(hWOut,&wh,sizeof(WAVEHDR));
                    
		return 0;

	case MM_WOM_DONE: /* 再生終了 */

		waveOutUnprepareHeader(hWOut,&wh,sizeof(WAVEHDR));
		waveOutClose(hWOut);

		return 0;

	case WM_DESTROY : // 終了処理

		PostQuitMessage(0);

		return 0;

	}

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

}