Initial implementation of SDL sound (not quite working...)

2024-11-13 07:05:12 +01:00 · 2010-03-13 12:09:29 +00:00 · 2010-03-13 12:09:29 +00:00 · f731ceafa9
commit f731ceafa9
parent a7e9b707d0
1 changed files with 156 additions and 0 deletions
--- a/Src/SID_SDL.h
+++ b/Src/SID_SDL.h
@ -0,0 +1,156 @@
+/*
+ *  SID_SDL.h - 6581 emulation, SDL specific stuff
+ *
+ *  Frodo (C) 1994-1997,2002-2005 Christian Bauer
+ *
+ *  SDL stuff by Simon Kagstrom
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <SDL.h>
+#include <SDL_mixer.h>
+
+#include "VIC.h"
+
+static SDL_AudioSpec spec;
+
+#define FRODO_SNDBUF 512
+#define SOUNDBUFSIZE 2048
+#define N_BUFS 8
+
+static int16 soundbuffer[N_BUFS][FRODO_SNDBUF];
+static int head, tail;
+
+static void fill_audio(void *udata, Uint8 *stream, int len)
+{
+	const int sz = FRODO_SNDBUF * 2;
+	int off = 0;
+
+	memset(stream, 0, len);
+	while (tail != head)
+	{
+		//printf("Copying %d bytes at off %d, tail %d, head %d\n", len, off, tail, head);
+		memcpy(stream + off, soundbuffer[tail], sz);
+		off += sz;
+		if (off >= len)
+			break;
+		tail = (tail + 1) % N_BUFS;
+	}
+}
+
+/*
+ *  Initialization
+ */
+
+void DigitalRenderer::init_sound(void)
+{
+	this->sndbufsize = FRODO_SNDBUF;
+
+	/* Set the audio format */
+	spec.freq = 32000;
+	spec.format = AUDIO_S16SYS;
+	spec.channels = 1;    /* 1 = mono, 2 = stereo */
+	spec.samples = SOUNDBUFSIZE;
+	spec.callback = fill_audio;
+	spec.userdata = (void*)this;
+
+	ready = false;
+	if ( SDL_OpenAudio(&spec, NULL) < 0 ) {
+		fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
+		return ;
+	}
+
+	this->sound_buffer = new int16[this->sndbufsize];
+	ready = true;
+	SDL_PauseAudio(0);
+}
+
+
+/*
+ *  Destructor
+ */
+
+DigitalRenderer::~DigitalRenderer()
+{
+	SDL_CloseAudio();
+}
+
+
+/*
+ *  Pause sound output
+ */
+
+void DigitalRenderer::Pause(void)
+{
+	SDL_PauseAudio(1);
+}
+
+
+/*
+ * Resume sound output
+ */
+
+void DigitalRenderer::Resume(void)
+{
+	SDL_PauseAudio(0);
+}
+
+
+/*
+ * Fill buffer, sample volume (for sampled voice)
+ */
+
+void DigitalRenderer::PushVolume(uint8 vol)
+{
+	static int divisor = 0;
+	static int to_output = 0;
+
+	sample_buf[sample_in_ptr] = volume;
+	sample_in_ptr = (sample_in_ptr + 1) % SAMPLE_BUF_SIZE;
+
+	/*
+	 * Now see how many samples have to be added for this line
+	 */
+	divisor += SAMPLE_FREQ;
+	while (divisor >= 0)
+	{
+		divisor -= TOTAL_RASTERS*SCREEN_FREQ;
+		to_output++;
+	}
+
+	if (to_output >= sndbufsize) {
+		int datalen = sndbufsize;
+		to_output -= datalen;
+
+
+		SDL_LockAudio();
+		calc_buffer(soundbuffer[head], datalen * 2);
+		head = (head + 1) % N_BUFS;
+		if (head == tail)
+			printf("Uh oh, hit the tail\n");
+		SDL_UnlockAudio();
+	}
+}
+
+
+void DigitalRenderer::EmulateLine(void)
+{
+	if (!ready)
+		return;
+	this->PushVolume(volume);
+}