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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#ifndef _SFX_MIXER_H_
#define _SFX_MIXER_H_
#include "sci/include/sfx_pcm.h"
namespace Sci {
#define SFX_PCM_FEED_MODE_ALIVE 0
#define SFX_PCM_FEED_MODE_DEAD 1
/** Finitary unsigned rational numbers */
struct sfx_pcm_urat_t {
int nom, den;
int val;
/* Total value: val + nom/den, where (nom < den) guaranteed. */
};
struct twochannel_data {
int left, right;
};
typedef struct {
sfx_pcm_feed_t *feed;
/* The following fields are for use by the mixer only and must not be
** touched by pcm_feed code. */
byte *buf; /* dynamically allocated buffer for this feed, used in some circumstances. */
int buf_size; /* Number of frames that fit into the buffer */
sfx_pcm_urat_t spd; /* source frames per destination frames */
sfx_pcm_urat_t scount; /* Frame counter, backed up in between calls */
int frame_bufstart; /* Left-over frames at the beginning of the buffer */
int mode; /* Whether the feed is alive or pending destruction */
int pending_review; /* Timestamp needs to be checked for this stream */
twochannel_data ch_old, ch_new; /* Intermediate results of output computation */
} sfx_pcm_feed_state_t;
typedef struct _sfx_pcm_mixer {
/* Mixers are the heart of all matters PCM. They take PCM data from subscribed feeds,
** mix it (hence the name) and ask the pcm device they are attached to to play the
** result. */
const char *name;
const char *version;
int (*init)(struct _sfx_pcm_mixer *self, sfx_pcm_device_t *device);
/* Initialises the mixer
** Parameters: (sfx_pcm_mixer_t *) self: Self reference
** (sfx_pcm_device_t *) device: An _already initialised_ PCM output driver
** Returns : (int) SFX_OK on success, SFX_ERROR otherwise
*/
void (*exit)(struct _sfx_pcm_mixer *self);
/* Uninitialises the mixer
** Parameters: (sfx_pcm_mixer_t *) self: Self reference
** Also uninitialises all feeds and the attached output device.
*/
void (*subscribe)(struct _sfx_pcm_mixer *self, sfx_pcm_feed_t *feed);
/* Subscribes the mixer to a new feed
** Parameters: (sfx_pcm_mixer_t *) self: Self reference
** (sfx_pcm_feed_t *) feed: The feed to subscribe to
*/
void (*pause)(struct _sfx_pcm_mixer *self);
/* Pauses the processing of input and output
*/
void (*resume)(struct _sfx_pcm_mixer *self);
/* Resumes the processing of input and output after a pause
*/
int (*process)(struct _sfx_pcm_mixer *self);
/* Processes all feeds, mixes their results, and passes everything to the output device
** Returns : (int) SFX_OK on success, SFX_ERROR otherwise (output device error or
** internal assertion failure)
** Effects : All feeds are poll()ed, and the device is asked to output(). Buffer size
** depends on the time that has passed since the last call to process(), if
** any.
*/
int feeds_nr;
int feeds_allocd;
sfx_pcm_feed_state_t *feeds;
sfx_pcm_device_t *dev;
void *private_bits;
} sfx_pcm_mixer_t;
sfx_pcm_mixer_t *
sfx_pcm_find_mixer(char *name);
/* Looks up a mixer by name, or a default mixer
** Parameters: (char *) name: Name of the mixer to look for, or NULL to
** take a default
*/
extern sfx_pcm_mixer_t *mixer; /* _THE_ global pcm mixer */
sfx_pcm_mixer_t* getMixer();
} // End of namespace Sci
#endif /* !defined(_SFX_MIXER_H_) */
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