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https://github.com/n64dev/cen64.git
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384f06d369
Most carts only seem to use one frequency. Add a dirty hack to change the frequency on the fly so things sound less horrendous.
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
//
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// ai/context.c: Sound card context management.
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//
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// CEN64: Cycle-Accurate Nintendo 64 Emulator.
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// Copyright (C) 2015, Tyler J. Stachecki.
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//
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// This file is subject to the terms and conditions defined in
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// 'LICENSE', which is part of this source code package.
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//
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#include "common.h"
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#include "ai/context.h"
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#include <AL/al.h>
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#include <AL/alc.h>
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// Creates and initializes an audio context.
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int ai_context_create(struct cen64_ai_context *context) {
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uint8_t buf[8];
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unsigned i;
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context->cur_frequency = 31985;
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if ((context->dev = alcOpenDevice(NULL)) == NULL) {
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printf("Failed to open the OpenAL device.\n");
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return 1;
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}
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if ((context->ctx = alcCreateContext(context->dev, NULL)) == NULL) {
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printf("Failed to create an OpenAL context.\n");
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alcCloseDevice(context->dev);
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return 1;
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}
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alcMakeContextCurrent(context->ctx);
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// Context/device is setup, create some buffers and a source.
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alGenBuffers(sizeof(context->buffers) / sizeof(*context->buffers),
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context->buffers);
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if (alGetError() != AL_NO_ERROR) {
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alcMakeContextCurrent(NULL);
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alcDestroyContext(context->ctx);
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alcCloseDevice(context->dev);
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}
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alGenSources(1, &context->source);
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if (alGetError() != AL_NO_ERROR) {
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alDeleteBuffers(sizeof(context->buffers) / sizeof(*context->buffers),
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context->buffers);
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alcMakeContextCurrent(NULL);
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alcDestroyContext(context->ctx);
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alcCloseDevice(context->dev);
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}
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// Queue/prime buffers, clear them to prevent pops.
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// Playing a little test also allows us to verify
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// that we (probably) won't get weird OpenAL errors
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// later on if things work now.
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memset(buf, 0x0, sizeof(buf));
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for (i = 0; i < sizeof(context->buffers) / sizeof(*context->buffers); i++)
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alBufferData(context->buffers[i], AL_FORMAT_STEREO16,
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buf, sizeof(buf), context->cur_frequency);
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alSourceQueueBuffers(context->source,
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sizeof(context->buffers) / sizeof(*context->buffers),
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context->buffers);
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alSourcePlay(context->source);
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if (alGetError() != AL_NO_ERROR) {
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ai_context_destroy(context);
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return 1;
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}
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// Now wait for them to drain.
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while (1) {
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ALint val;
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alGetSourcei(context->source, AL_BUFFERS_PROCESSED, &val);
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if (val == (sizeof(context->buffers) / sizeof(*context->buffers)))
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break;
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}
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if (alGetError() != AL_NO_ERROR) {
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ai_context_destroy(context);
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return 1;
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}
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context->unqueued_buffers = 0;
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return 0;
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}
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// Destroys audio contexts made with ai_context_create.
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void ai_context_destroy(struct cen64_ai_context *context) {
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alDeleteSources(1, &context->source);
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alDeleteBuffers(sizeof(context->buffers) / sizeof(*context->buffers),
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context->buffers);
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alcMakeContextCurrent(NULL);
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alcDestroyContext(context->ctx);
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alcCloseDevice(context->dev);
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}
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// Generate buffers for some given frequency.
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int ai_switch_frequency(struct cen64_ai_context *context, ALint frequency) {
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alDeleteSources(1, &context->source);
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alDeleteBuffers(sizeof(context->buffers) / sizeof(*context->buffers),
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context->buffers);
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alGenBuffers(sizeof(context->buffers) / sizeof(*context->buffers),
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context->buffers);
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alGenSources(1, &context->source);
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context->cur_frequency = frequency;
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context->unqueued_buffers = sizeof(context->buffers) /
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sizeof(*context->buffers);
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return 0;
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}
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