Genesis-Plus-GX/source/sound/blip.h

/* Fast sound synthesis buffer for use in real-time emulators of electronic
sound generator chips like those in early video game consoles. Uses linear
interpolation. Higher-quality versions are available that use sinc-based
band-limited synthesis. */

#ifndef BLIP_H
#define BLIP_H

#ifdef __cplusplus
  extern "C" {
#endif

/* Creates a new blip_buffer with specified input clock rate, output
sample rate, and size (in samples), or returns NULL if out of memory. */
typedef struct blip_buffer_t blip_buffer_t;
blip_buffer_t* blip_alloc( double clock_rate, double sample_rate, int size );

/* Frees memory used by a blip_buffer. No effect if NULL is passed. */
void blip_free( blip_buffer_t* );

/* Removes all samples and clears buffer. */
void blip_clear( blip_buffer_t* );

/* Adds an amplitude transition of delta at specified time in source clocks.
Delta can be negative. */
void blip_add( blip_buffer_t*, int time, int delta );

/* Number of additional clocks needed until n samples will be available.
If buffer cannot even hold n samples, returns number of clocks until buffer
becomes full. */
int blip_clocks_needed( const blip_buffer_t*, int samples_needed );

/* Ends current time frame of specified duration and make its samples available
(along with any still-unread samples) for reading with read_samples(), then
begins a new time frame at the end of the current frame. */
void blip_end_frame( blip_buffer_t*, int duration );

/* Number of samples available for reading with read(). */
int blip_samples_avail( const blip_buffer_t* );

/* Reads at most n samples out of buffer into out, removing them from from
the buffer. */
int blip_read_samples( blip_buffer_t*, short out [], int stereo);

#ifdef __cplusplus
  }
#endif

#endif