shithub: cstory

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Document MakePixToneObject a bit more

--- a/src/Sound.cpp

+++ b/src/Sound.cpp

@@ -297,22 +297,19 @@

 int MakePixToneObject(const PIXTONEPARAMETER *ptp, int ptp_num, int no)

 {

 	// For some reason, this function creates an entire WAV file header,

-	// when it only needs a WAVEFORMATEX

+	// when it only needs a WAVEFORMATEX.

+	// From what I can tell, there's no struct like this in the Windows

+	// headers, so Pixel must have defined it manually, just like this:

 	typedef struct WavHeader

 	{

-		CHAR riff[4];

-		DWORD wav_size;

-		CHAR wave[4];

-		CHAR fmt[4];

-		DWORD fmt_chunk_size;

-		WORD audio_format;

-		WORD num_channels;

-		DWORD sample_rate;

-		DWORD byte_rate;

-		WORD sample_alignment;

-		WORD bit_depth;

-		CHAR data[4];

-		DWORD data_bytes;

+		FOURCC riff_id;

+		DWORD riff_size;

+		FOURCC wave_id;

+		FOURCC fmt_id;

+		DWORD fmt_size;

+		PCMWAVEFORMAT format;

+		FOURCC data_id;

+		DWORD data_size;

 	} WavHeader;

 	int sample_count;

@@ -327,23 +324,23 @@

 		return 0;

 	const char *riff = "RIFF";

-	const char *fmt = "fmt ";

+	const char *fmt  = "fmt ";

 	const char *wave = "WAVE";

 	const char *data = "data";

-	wav_header.bit_depth = 8;

-	wav_header.sample_rate = 22050;

-	wav_header.num_channels = 1;

-	wav_header.audio_format = WAVE_FORMAT_PCM;

-	wav_header.fmt_chunk_size = 16;

-	memcpy(wav_header.riff, riff, 4);

-	memcpy(wav_header.fmt, fmt, 4);

-	memcpy(wav_header.wave, wave, 4);

-	memcpy(wav_header.data, data, 4);

-	wav_header.sample_alignment = (wav_header.bit_depth / 8) * wav_header.num_channels;

-	wav_header.byte_rate = (wav_header.bit_depth / 8) * wav_header.num_channels * wav_header.sample_rate;

-	wav_header.data_bytes = wav_header.sample_alignment * ptp->size;	// Note that this uses ptp->size, not sample_count. If this header were ever used, it would be incorrect.

-	wav_header.wav_size = wav_header.data_bytes + 36;

+	wav_header.format.wBitsPerSample = 8;

+	wav_header.format.wf.nSamplesPerSec = 22050;

+	wav_header.format.wf.nChannels = 1;

+	wav_header.format.wf.wFormatTag = WAVE_FORMAT_PCM;

+	wav_header.fmt_size = sizeof(wav_header.format);

+	memcpy(&wav_header.riff_id, riff, sizeof(FOURCC));

+	memcpy(&wav_header.fmt_id, fmt, sizeof(FOURCC));

+	memcpy(&wav_header.wave_id, wave, sizeof(FOURCC));

+	memcpy(&wav_header.data_id, data, sizeof(FOURCC));

+	wav_header.format.wf.nBlockAlign = (wav_header.format.wBitsPerSample / 8) * wav_header.format.wf.nChannels;

+	wav_header.format.wf.nAvgBytesPerSec = (wav_header.format.wBitsPerSample / 8) * wav_header.format.wf.nChannels * wav_header.format.wf.nSamplesPerSec;

+	wav_header.data_size = wav_header.format.wf.nBlockAlign * ptp->size;	// Note that this uses ptp->size, not sample_count. If this header were ever used, it would be incorrect.

+	wav_header.riff_size = sizeof(wav_header) - 8 + wav_header.data_size;

 	ptp_pointer = ptp;

 	sample_count = 0;

@@ -360,7 +357,7 @@

 	dsbd.dwSize = sizeof(dsbd);

 	dsbd.dwFlags = DSBCAPS_STATIC | DSBCAPS_GLOBALFOCUS | DSBCAPS_CTRLPAN | DSBCAPS_CTRLVOLUME | DSBCAPS_CTRLFREQUENCY;

 	dsbd.dwBufferBytes = sample_count;

-	dsbd.lpwfxFormat = (WAVEFORMATEX*)&wav_header.audio_format;

+	dsbd.lpwfxFormat = (LPWAVEFORMATEX)&wav_header.format;

 	if (lpDS->CreateSoundBuffer(&dsbd, &lpSECONDARYBUFFER[no], 0) != DS_OK)

 		return -1;