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 <mgba/core/core.h>
  9#include <mgba/core/thread.h>
 10#include <mgba/internal/gba/audio.h>
 11#include <mgba/internal/gba/gba.h>
 12
 13#include <mgba/core/blip_buf.h>
 14
 15#define BUFFER_SIZE (GBA_AUDIO_SAMPLES >> 2)
 16
 17mLOG_DEFINE_CATEGORY(SDL_AUDIO, "SDL Audio", "platform.sdl.audio");
 18
 19static void _mSDLAudioCallback(void* context, Uint8* data, int len);
 20
 21bool mSDLInitAudio(struct mSDLAudio* context, struct mCoreThread* threadContext) {
 22	if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) {
 23		mLOG(SDL_AUDIO, ERROR, "Could not initialize SDL sound system: %s", SDL_GetError());
 24		return false;
 25	}
 26
 27	context->desiredSpec.freq = context->sampleRate;
 28	context->desiredSpec.format = AUDIO_S16SYS;
 29	context->desiredSpec.channels = 2;
 30	context->desiredSpec.samples = context->samples;
 31	context->desiredSpec.callback = _mSDLAudioCallback;
 32	context->desiredSpec.userdata = context;
 33
 34#if SDL_VERSION_ATLEAST(2, 0, 0)
 35	context->deviceId = SDL_OpenAudioDevice(0, 0, &context->desiredSpec, &context->obtainedSpec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);
 36	if (context->deviceId == 0) {
 37#else
 38	if (SDL_OpenAudio(&context->desiredSpec, &context->obtainedSpec) < 0) {
 39#endif
 40		mLOG(SDL_AUDIO, ERROR, "Could not open SDL sound system");
 41		return false;
 42	}
 43	context->samples = context->obtainedSpec.samples;
 44	context->core = 0;
 45
 46	if (threadContext) {
 47		context->core = threadContext->core;
 48		context->sync = &threadContext->sync;
 49
 50#if SDL_VERSION_ATLEAST(2, 0, 0)
 51		SDL_PauseAudioDevice(context->deviceId, 0);
 52#else
 53		SDL_PauseAudio(0);
 54#endif
 55	}
 56
 57	return true;
 58}
 59
 60void mSDLDeinitAudio(struct mSDLAudio* context) {
 61	UNUSED(context);
 62#if SDL_VERSION_ATLEAST(2, 0, 0)
 63	SDL_PauseAudioDevice(context->deviceId, 1);
 64	SDL_CloseAudioDevice(context->deviceId);
 65#else
 66	SDL_PauseAudio(1);
 67	SDL_CloseAudio();
 68#endif
 69	SDL_QuitSubSystem(SDL_INIT_AUDIO);
 70}
 71
 72void mSDLPauseAudio(struct mSDLAudio* context) {
 73#if SDL_VERSION_ATLEAST(2, 0, 0)
 74	SDL_PauseAudioDevice(context->deviceId, 1);
 75#else
 76	UNUSED(context);
 77	SDL_PauseAudio(1);
 78#endif
 79}
 80
 81void mSDLResumeAudio(struct mSDLAudio* context) {
 82#if SDL_VERSION_ATLEAST(2, 0, 0)
 83	SDL_PauseAudioDevice(context->deviceId, 0);
 84#else
 85	UNUSED(context);
 86	SDL_PauseAudio(0);
 87#endif
 88}
 89
 90static void _mSDLAudioCallback(void* context, Uint8* data, int len) {
 91	struct mSDLAudio* audioContext = context;
 92	if (!context || !audioContext->core) {
 93		memset(data, 0, len);
 94		return;
 95	}
 96	blip_t* left = NULL;
 97	blip_t* right = NULL;
 98	int32_t clockRate = GBA_ARM7TDMI_FREQUENCY;
 99	if (audioContext->core) {
100		left = audioContext->core->getAudioChannel(audioContext->core, 0);
101		right = audioContext->core->getAudioChannel(audioContext->core, 1);
102		clockRate = audioContext->core->frequency(audioContext->core);
103	}
104	double fauxClock = 1;
105	if (audioContext->sync) {
106		if (audioContext->sync->fpsTarget > 0) {
107			fauxClock = GBAAudioCalculateRatio(1, audioContext->sync->fpsTarget, 1);
108		}
109		mCoreSyncLockAudio(audioContext->sync);
110	}
111	blip_set_rates(left, clockRate, audioContext->obtainedSpec.freq * fauxClock);
112	blip_set_rates(right, clockRate, audioContext->obtainedSpec.freq * fauxClock);
113	len /= 2 * audioContext->obtainedSpec.channels;
114	int available = blip_samples_avail(left);
115	if (available > len) {
116		available = len;
117	}
118	blip_read_samples(left, (short*) data, available, audioContext->obtainedSpec.channels == 2);
119	if (audioContext->obtainedSpec.channels == 2) {
120		blip_read_samples(right, ((short*) data) + 1, available, 1);
121	}
122
123	if (audioContext->sync) {
124		mCoreSyncConsumeAudio(audioContext->sync);
125	}
126	if (available < len) {
127		memset(((short*) data) + audioContext->obtainedSpec.channels * available, 0, (len - available) * audioContext->obtainedSpec.channels * sizeof(short));
128	}
129}