mirror of https://github.com/trudnai/Steve2.git
139 lines
3.5 KiB
C
139 lines
3.5 KiB
C
//
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// speaker.c
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// A2Mac
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//
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// Created by Tamas Rudnai on 5/9/20.
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// Copyright © 2020 GameAlloy. All rights reserved.
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//
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <math.h>
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#include <OpenAL/al.h>
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#include <OpenAL/alc.h>
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#include "speaker.h"
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#define CASE_RETURN(err) case (err): return #err
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const char* al_err_str(ALenum err) {
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switch(err) {
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CASE_RETURN(AL_NO_ERROR);
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CASE_RETURN(AL_INVALID_NAME);
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CASE_RETURN(AL_INVALID_ENUM);
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CASE_RETURN(AL_INVALID_VALUE);
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CASE_RETURN(AL_INVALID_OPERATION);
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CASE_RETURN(AL_OUT_OF_MEMORY);
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}
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return "unknown";
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}
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#undef CASE_RETURN
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#define __al_check_error(file,line) \
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do { \
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ALenum err = alGetError(); \
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for(; err != AL_NO_ERROR; err = alGetError()) { \
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printf( "AL Error %s at %s:%d\n", al_err_str(err), file, line ); \
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} \
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} while(0)
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#define al_check_error() \
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__al_check_error(__FILE__, __LINE__)
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ALCdevice *dev = NULL;
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ALCcontext *ctx = NULL;
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ALuint spkr_buf = 0;
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ALuint spkr_src = 0;
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// we start with the max, because otherwise the speaker clicks
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int spkr_level = SPKR_LEVEL_MAX;
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const int spkr_fps = 20;
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const int spkr_seconds = 1;
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const unsigned spkr_sample_rate = 44100;
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const unsigned spkr_buf_size = spkr_seconds * spkr_sample_rate;
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char spkr_samples [ spkr_buf_size ];
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unsigned spkr_sample_idx = 0;
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// initialize OpenAL
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void spkr_init() {
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const char *defname = alcGetString(NULL, ALC_DEFAULT_DEVICE_SPECIFIER);
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printf( "Default device: %s\n", defname );
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dev = alcOpenDevice(defname);
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ctx = alcCreateContext(dev, NULL);
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alcMakeContextCurrent(ctx);
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// Fill buffer with zeros
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memset( spkr_samples, spkr_level, spkr_buf_size );
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}
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// Dealloc OpenAL
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void spkr_exit() {
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ALCdevice *dev = NULL;
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ALCcontext *ctx = NULL;
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ctx = alcGetCurrentContext();
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dev = alcGetContextsDevice(ctx);
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alcMakeContextCurrent(NULL);
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alcDestroyContext(ctx);
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alcCloseDevice(dev);
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al_check_error();
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}
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void spkr_play() {
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if ( spkr_sample_idx ) {
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if ( spkr_src ) {
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alSourceStop(spkr_src);
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al_check_error();
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alSourcei(spkr_src, AL_BUFFER, 0);
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al_check_error();
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}
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if ( spkr_buf ) {
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alDeleteBuffers(1, &spkr_buf);
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al_check_error();
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}
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// Create buffer to store samples
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spkr_buf = 0;
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alGenBuffers(1, &spkr_buf);
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al_check_error();
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// Download buffer to OpenAL
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alBufferData(spkr_buf, AL_FORMAT_MONO8, spkr_samples, spkr_buf_size / spkr_fps, spkr_sample_rate);
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al_check_error();
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// Set-up sound source and play buffer
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spkr_src = 0;
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alGenSources(1, &spkr_src);
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alSourcei(spkr_src, AL_BUFFER, spkr_buf);
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alSourcei(spkr_src, AL_LOOPING, 0);
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alSourcePlay(spkr_src);
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ALint secoffset = 0;
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alGetSourcei( spkr_src, AL_BYTE_OFFSET, &secoffset );
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// ccopy slack buffer to the top, so we will not lose the edges
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memcpy(spkr_samples, spkr_samples + secoffset, spkr_buf_size - spkr_buf_size / spkr_fps);
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// clear the slack buffer , so we can fill it up by new data
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memset(spkr_samples + secoffset, spkr_level, spkr_buf_size - spkr_buf_size / spkr_fps);
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// start from the beginning
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spkr_sample_idx = 0;
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}
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else {
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alSourceStop(spkr_src);
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}
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}
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