157 lines
3.1 KiB
C
157 lines
3.1 KiB
C
/*
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* SID_SDL.h - 6581 emulation, SDL specific stuff
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*
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* Frodo (C) 1994-1997,2002-2005 Christian Bauer
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*
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* SDL stuff by Simon Kagstrom
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <unistd.h>
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#include <fcntl.h>
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#include <SDL.h>
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#include "VIC.h"
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static SDL_AudioSpec spec;
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#define FRODO_SNDBUF 512
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#define SOUNDBUFSIZE 1536
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#define N_BUFS 8
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static int16 soundbuffer[N_BUFS][FRODO_SNDBUF];
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static int head, tail;
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static void fill_audio(void *udata, Uint8 *stream, int len)
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{
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const int sz = FRODO_SNDBUF * 2;
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int off = 0;
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memset(stream, 0, len);
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while (tail != head)
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{
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//printf("Copying %d bytes at off %d, tail %d, head %d\n", len, off, tail, head);
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memcpy(stream + off, soundbuffer[tail], sz);
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off += sz;
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if (off >= len)
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break;
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tail = (tail + 1) % N_BUFS;
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}
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}
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/*
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* Initialization
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*/
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void DigitalRenderer::init_sound(void)
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{
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this->sndbufsize = FRODO_SNDBUF;
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/* Set the audio format */
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spec.freq = 32000;
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spec.format = AUDIO_S16SYS;
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spec.channels = 1; /* 1 = mono, 2 = stereo */
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spec.samples = SOUNDBUFSIZE;
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spec.callback = fill_audio;
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spec.userdata = (void*)this;
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ready = false;
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if ( SDL_OpenAudio(&spec, NULL) < 0 ) {
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fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
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return ;
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}
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this->sound_buffer = new int16[this->sndbufsize];
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memset(this->sound_buffer, 0, sizeof(int16) * this->sndbufsize);
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ready = true;
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SDL_PauseAudio(0);
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}
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/*
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* Destructor
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*/
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DigitalRenderer::~DigitalRenderer()
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{
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SDL_CloseAudio();
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}
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/*
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* Pause sound output
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*/
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void DigitalRenderer::Pause(void)
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{
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SDL_PauseAudio(1);
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}
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/*
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* Resume sound output
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*/
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void DigitalRenderer::Resume(void)
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{
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SDL_PauseAudio(0);
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}
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/*
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* Fill buffer, sample volume (for sampled voice)
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*/
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void DigitalRenderer::PushVolume(uint8 vol)
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{
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static int divisor = 0;
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static int to_output = 0;
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sample_buf[sample_in_ptr] = volume;
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sample_in_ptr = (sample_in_ptr + 1) % SAMPLE_BUF_SIZE;
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/*
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* Now see how many samples have to be added for this line
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*/
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divisor += SAMPLE_FREQ;
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while (divisor >= 0)
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{
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divisor -= TOTAL_RASTERS*SCREEN_FREQ;
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to_output++;
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}
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if (to_output >= sndbufsize) {
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int datalen = sndbufsize;
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to_output -= datalen;
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SDL_LockAudio();
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calc_buffer(soundbuffer[head], datalen * 2);
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head = (head + 1) % N_BUFS;
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if (head == tail) {
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tail = (head + 1) % N_BUFS;
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}
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SDL_UnlockAudio();
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}
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}
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void DigitalRenderer::EmulateLine(void)
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{
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if (!ready)
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return;
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this->PushVolume(volume);
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}
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