1/* Copyright (c) 2013-2015 Jeffrey Pfau
  2 *
  3 * This Source Code Form is subject to the terms of the Mozilla Public
  4 * License, v. 2.0. If a copy of the MPL was not distributed with this
  5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  6#include "sdl-audio.h"
  7
  8#include "gba/gba.h"
  9#include "gba/supervisor/thread.h"
 10
 11#include "third-party/blip_buf/blip_buf.h"
 12
 13#define BUFFER_SIZE (GBA_AUDIO_SAMPLES >> 2)
 14
 15static void _GBSDLAudioCallback(void* context, Uint8* data, int len);
 16
 17bool GBSDLInitAudio(struct GBSDLAudio* context, struct GBAThread* threadContext) {
 18	if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) {
 19		GBALog(0, GBA_LOG_ERROR, "Could not initialize SDL sound system: %s", SDL_GetError());
 20		return false;
 21	}
 22
 23	context->desiredSpec.freq = context->sampleRate;
 24	context->desiredSpec.format = AUDIO_S16SYS;
 25	context->desiredSpec.channels = 2;
 26	context->desiredSpec.samples = context->samples;
 27	context->desiredSpec.callback = _GBSDLAudioCallback;
 28	context->desiredSpec.userdata = context;
 29
 30#if SDL_VERSION_ATLEAST(2, 0, 0)
 31	context->deviceId = SDL_OpenAudioDevice(0, 0, &context->desiredSpec, &context->obtainedSpec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);
 32	if (context->deviceId == 0) {
 33#else
 34	if (SDL_OpenAudio(&context->desiredSpec, &context->obtainedSpec) < 0) {
 35#endif
 36		GBALog(0, GBA_LOG_ERROR, "Could not open SDL sound system");
 37		return false;
 38	}
 39	context->samples = context->obtainedSpec.samples;
 40	context->psg = 0;
 41	context->thread = 0;
 42
 43	if (threadContext) {
 44		context->thread = threadContext;
 45		float ratio = GBAAudioCalculateRatio(0x8000, threadContext->fpsTarget, 44100);
 46		threadContext->audioBuffers = context->samples / ratio;
 47		if (context->samples > threadContext->audioBuffers) {
 48			threadContext->audioBuffers = context->samples * 2;
 49		}
 50
 51#if SDL_VERSION_ATLEAST(2, 0, 0)
 52		SDL_PauseAudioDevice(context->deviceId, 0);
 53#else
 54		SDL_PauseAudio(0);
 55#endif
 56	}
 57
 58	return true;
 59}
 60
 61void GBSDLDeinitAudio(struct GBSDLAudio* context) {
 62	UNUSED(context);
 63	context->psg = 0;
 64#if SDL_VERSION_ATLEAST(2, 0, 0)
 65	SDL_PauseAudioDevice(context->deviceId, 1);
 66	SDL_CloseAudioDevice(context->deviceId);
 67#else
 68	SDL_PauseAudio(1);
 69	SDL_CloseAudio();
 70#endif
 71	SDL_QuitSubSystem(SDL_INIT_AUDIO);
 72}
 73
 74void GBSDLPauseAudio(struct GBSDLAudio* context) {
 75#if SDL_VERSION_ATLEAST(2, 0, 0)
 76	SDL_PauseAudioDevice(context->deviceId, 1);
 77#else
 78	UNUSED(context);
 79	SDL_PauseAudio(1);
 80#endif
 81}
 82
 83void GBSDLResumeAudio(struct GBSDLAudio* context) {
 84#if SDL_VERSION_ATLEAST(2, 0, 0)
 85	SDL_PauseAudioDevice(context->deviceId, 0);
 86#else
 87	UNUSED(context);
 88	SDL_PauseAudio(0);
 89#endif
 90}
 91
 92static void _GBSDLAudioCallback(void* context, Uint8* data, int len) {
 93	struct GBSDLAudio* audioContext = context;
 94	if (!context || (!audioContext->psg && !audioContext->thread)) {
 95		memset(data, 0, len);
 96		return;
 97	}
 98	struct GBAudio* psg = audioContext->psg;
 99	if (!psg) {
100		psg = &audioContext->thread->gba->audio.psg;
101	}
102	double fauxClock = 1;
103	if (audioContext->thread) {
104		fauxClock = GBAAudioCalculateRatio(1, audioContext->thread->fpsTarget, 1);
105		mCoreSyncLockAudio(&audioContext->thread->sync);
106	}
107	blip_set_rates(psg->left, psg->clockRate, audioContext->obtainedSpec.freq * fauxClock);
108	blip_set_rates(psg->right, psg->clockRate, audioContext->obtainedSpec.freq * fauxClock);
109	len /= 2 * audioContext->obtainedSpec.channels;
110	int available = blip_samples_avail(psg->left);
111	if (available > len) {
112		available = len;
113	}
114	blip_read_samples(psg->left, (short*) data, available, audioContext->obtainedSpec.channels == 2);
115	if (audioContext->obtainedSpec.channels == 2) {
116		blip_read_samples(psg->right, ((short*) data) + 1, available, 1);
117	}
118
119	if (audioContext->thread) {
120		mCoreSyncConsumeAudio(&audioContext->thread->sync);
121	}
122	if (available < len) {
123		memset(((short*) data) + audioContext->obtainedSpec.channels * available, 0, (len - available) * audioContext->obtainedSpec.channels * sizeof(short));
124	}
125}