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120 lines
4.0 KiB
C
120 lines
4.0 KiB
C
/***************************************************************************
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sfx_mixer.h Copyright (C) 2003,04 Christoph Reichenbach
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This program may be modified and copied freely according to the terms of
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the GNU general public license (GPL), as long as the above copyright
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notice and the licensing information contained herein are preserved.
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Please refer to www.gnu.org for licensing details.
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This work is provided AS IS, without warranty of any kind, expressed or
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implied, including but not limited to the warranties of merchantibility,
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noninfringement, and fitness for a specific purpose. The author will not
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be held liable for any damage caused by this work or derivatives of it.
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By using this source code, you agree to the licensing terms as stated
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above.
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Please contact the maintainer for bug reports or inquiries.
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Current Maintainer:
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Christoph Reichenbach (CR) <jameson@linuxgames.com>
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***************************************************************************/
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#ifndef _SFX_MIXER_H_
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#define _SFX_MIXER_H_
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#include "sci/include/sfx_pcm.h"
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#define SFX_PCM_FEED_MODE_ALIVE 0
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#define SFX_PCM_FEED_MODE_DEAD 1
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struct twochannel_data {
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int left, right;
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};
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typedef struct {
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sfx_pcm_feed_t *feed;
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/* The following fields are for use by the mixer only and must not be
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** touched by pcm_feed code. */
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byte *buf; /* dynamically allocated buffer for this feed, used in some circumstances. */
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int buf_size; /* Number of frames that fit into the buffer */
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sfx_pcm_urat_t spd; /* source frames per destination frames */
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sfx_pcm_urat_t scount; /* Frame counter, backed up in between calls */
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int frame_bufstart; /* Left-over frames at the beginning of the buffer */
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int mode; /* Whether the feed is alive or pending destruction */
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int pending_review; /* Timestamp needs to be checked for this stream */
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struct twochannel_data ch_old, ch_new; /* Intermediate results of output computation */
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} sfx_pcm_feed_state_t;
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typedef struct _sfx_pcm_mixer {
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/* Mixers are the heart of all matters PCM. They take PCM data from subscribed feeds,
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** mix it (hence the name) and ask the pcm device they are attached to to play the
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** result. */
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const char *name;
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const char *version;
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int (*init)(struct _sfx_pcm_mixer *self, sfx_pcm_device_t *device);
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/* Initialises the mixer
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** Parameters: (sfx_pcm_mixer_t *) self: Self reference
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** (sfx_pcm_device_t *) device: An _already initialised_ PCM output driver
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** Returns : (int) SFX_OK on success, SFX_ERROR otherwise
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*/
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void (*exit)(struct _sfx_pcm_mixer *self);
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/* Uninitialises the mixer
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** Parameters: (sfx_pcm_mixer_t *) self: Self reference
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** Also uninitialises all feeds and the attached output device.
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*/
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void (*subscribe)(struct _sfx_pcm_mixer *self, sfx_pcm_feed_t *feed);
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/* Subscribes the mixer to a new feed
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** Parameters: (sfx_pcm_mixer_t *) self: Self reference
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** (sfx_pcm_feed_t *) feed: The feed to subscribe to
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*/
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void (*pause)(struct _sfx_pcm_mixer *self);
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/* Pauses the processing of input and output
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*/
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void (*resume)(struct _sfx_pcm_mixer *self);
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/* Resumes the processing of input and output after a pause
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*/
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int (*process)(struct _sfx_pcm_mixer *self);
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/* Processes all feeds, mixes their results, and passes everything to the output device
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** Returns : (int) SFX_OK on success, SFX_ERROR otherwise (output device error or
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** internal assertion failure)
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** Effects : All feeds are poll()ed, and the device is asked to output(). Buffer size
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** depends on the time that has passed since the last call to process(), if
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** any.
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*/
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int feeds_nr;
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int feeds_allocd;
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sfx_pcm_feed_state_t *feeds;
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sfx_pcm_device_t *dev;
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void *private_bits;
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} sfx_pcm_mixer_t;
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sfx_pcm_mixer_t *
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sfx_pcm_find_mixer(char *name);
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/* Looks up a mixer by name, or a default mixer
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** Parameters: (char *) name: Name of the mixer to look for, or NULL to
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** take a default
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*/
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extern sfx_pcm_mixer_t *mixer; /* _THE_ global pcm mixer */
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#endif /* !defined(_SFX_MIXER_H_) */
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