PCM の基本

物理的な音の「波」
論理的な音の「点」

MMRESULT waveOutOpen(
	LPHWAVEOUT phwo , UINT uDeviceID,            
	LPWAVEFORMATEX pwfx ,
	DWORD dwCallback , DWORD dwCallbackInstance ,
	DWORD fdwOpen
);

typedef struct { 
    WORD  wFormatTag; 
    WORD  nChannels; 
    DWORD nSamplesPerSec; 
    DWORD nAvgBytesPerSec; 
    WORD  nBlockAlign; 
    WORD  wBitsPerSample; 
    WORD  cbSize; 
} WAVEFORMATEX;

void CALLBACK waveOutProc(
	HWAVEOUT hwo , UINT uMsg,         
	DWORD dwInstance,  
	DWORD dwParam1, DWORD dwParam2     
);

MMRESULT waveOutPrepareHeader(
	HWAVEOUT hwo , LPWAVEHDR pwh , UINT cbwh
);

typedef struct { 
    LPSTR  lpData; 
    DWORD  dwBufferLength; 
    DWORD  dwBytesRecorded; 
    DWORD  dwUser; 
    DWORD  dwFlags; 
    DWORD  dwLoops; 
    struct wavehdr_tag * lpNext; 
    DWORD  reserved; 
} WAVEHDR;

MMRESULT waveOutWrite(
	HWAVEOUT hwo , LPWAVEHDR pwh , UINT cbwh
);

MMRESULT waveOutUnprepareHeader(
	HWAVEOUT hwo , LPWAVEHDR pwh , UINT cbwh
);

#include <windows.h>
#define TITLE 	TEXT("Kitty on your lap")
#define SRATE 	11025

LRESULT CALLBACK WndProc(HWND hWnd , UINT msg , WPARAM wp , LPARAM lp) {
	static HWAVEOUT hWave;
	static BYTE *bWave;
	static WAVEHDR whdr;
	DWORD dwCount , dwWave = 0;
	WAVEFORMATEX wfe;

	switch (msg) {
	case WM_DESTROY:
		waveOutReset(hWave);
		waveOutUnprepareHeader(hWave , &whdr , sizeof(WAVEHDR));
		free(bWave);
		waveOutClose(hWave);
		PostQuitMessage(0);
		return 0;
	case WM_CREATE:
		bWave = malloc(SRATE);
		for (dwCount = 0 ; dwCount < SRATE ; dwCount++ , dwWave += 10) {
			if (dwWave > 256) dwWave = 0;
			*(bWave + dwCount) = dwWave;
		}	
		wfe.wFormatTag = WAVE_FORMAT_PCM;
		wfe.nChannels = 1;
		wfe.nSamplesPerSec = SRATE;
		wfe.nAvgBytesPerSec = SRATE;
		wfe.wBitsPerSample = 8;
		wfe.nBlockAlign = wfe.nChannels * wfe.wBitsPerSample / 8;

		waveOutOpen(&hWave ,
			WAVE_MAPPER , &wfe , 0 , 0 , CALLBACK_NULL);

		whdr.lpData = bWave;
		whdr.dwBufferLength = SRATE;
		whdr.dwFlags = WHDR_BEGINLOOP | WHDR_ENDLOOP;
		whdr.dwLoops = 5;
		waveOutPrepareHeader(hWave , &whdr , sizeof(WAVEHDR));
		waveOutWrite(hWave , &whdr , sizeof(WAVEHDR));
		return 0;
	}
	return DefWindowProc(hWnd , msg , wp , lp);
}

int WINAPI WinMain(HINSTANCE hInstance , HINSTANCE hPrevInstance ,
			PSTR lpCmdLine , int nCmdShow) {
	HWND hWnd;
	MSG msg;
	WNDCLASS winc;

	winc.style 		= CS_HREDRAW | CS_VREDRAW;
	winc.lpfnWndProc	= WndProc;
	winc.cbClsExtra		= winc.cbWndExtra	= 0;
	winc.hInstance		= hInstance;
	winc.hIcon		= LoadIcon(NULL , IDI_APPLICATION);
	winc.hCursor		= LoadCursor(NULL , IDC_ARROW);
	winc.hbrBackground	= (HBRUSH)GetStockObject(WHITE_BRUSH);
	winc.lpszMenuName	= NULL;
	winc.lpszClassName	= TEXT("KITTY");

	if (!RegisterClass(&winc)) return 1;

	hWnd = CreateWindow(
		TEXT("KITTY") , TITLE ,
		WS_OVERLAPPEDWINDOW | WS_VISIBLE ,
		CW_USEDEFAULT , CW_USEDEFAULT ,
		CW_USEDEFAULT , CW_USEDEFAULT ,
		NULL , NULL , hInstance , NULL
	);

	if (hWnd == NULL) return 1;

	while (GetMessage(&msg , NULL , 0 , 0 )) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return msg.wParam;
}

for (dwCount = 0 ; dwCount < SRATE ; dwCount++ , dwWave += 10) {
	if (dwWave == 256) dwWave = 0;
	*(bWave + dwCount) = dwWave;
}

waveOutOpen()

MMRESULT waveOutOpen(
	LPHWAVEOUT phwo , UINT uDeviceID,            
	LPWAVEFORMATEX pwfx ,
	DWORD dwCallback , DWORD dwCallbackInstance ,
	DWORD fdwOpen
);

waveOutProc()

void CALLBACK waveOutProc(
	HWAVEOUT hwo , UINT uMsg,         
	DWORD dwInstance,  
	DWORD dwParam1, DWORD dwParam2     
);

waveOutPrepareHeader()

MMRESULT waveOutPrepareHeader(
	HWAVEOUT hwo , LPWAVEHDR pwh , UINT cbwh
);

waveOutWrite()

MMRESULT waveOutWrite(
	HWAVEOUT hwo , LPWAVEHDR pwh , UINT cbwh
);

waveOutReset()

waveOutUnprepareHeader()

MMRESULT waveOutUnprepareHeader(
	HWAVEOUT hwo , LPWAVEHDR pwh , UINT cbwh
);

waveOutClose()