The AMP effector.

#include <audio_efx_amp.h> More...

Collaboration diagram for The AMP effector.:

Functions
void	audio_efx_amp (void)
	MSX The AMP effector for the libmsx audio replayer.
void	audio_efx_amp_set_volume (uint8_t volume)
	MSX Sets the main volume level to the AMP effector.
uint8_t	audio_efx_amp_get_volume (void)
	MSX Gets the current main volume level from the AMP effector.
void	audio_efx_amp_fadeout (uint8_t ticks)
	MSX Decrease the main volume level by one for each specified period of time.
void	audio_efx_amp_fadein (uint8_t ticks)
	MSX Increase the main volume level by one for each specified period of time.
int8_t	audio_efx_amp_get_fade (void)
	MSX Return the status of fade-in/out.

Detailed Description

#include <audio_efx_amp.h>

The AMP effector controls / attenuate the main-volume for all channels.

 c
#include <msx.h>
#include <audio.h>
#include <audio_efx_amp.h>
 
// Custom VSYNC interrupt handler.
void play(void) {
  audio_play();
  // To use AMP effector, call `audio_efx_amp()` every after `audio_play()`.
  audio_efx_amp();
}
 
void main(void) {
  audio_init();
  set_vsync_handler(play);
  for (;;) {
    await_vsync();
    // Get the current main-volume level.
    uint8_t vol = audio_efx_amp_get_volume();
    // ...
 
    // Set the main-volume level to 10.
    audio_efx_amp_set_volume(10);
    // ...
 
    // Decrease the main-volume level every 3 ticks.
    // (`0` means every ticks)
    audio_efx_amp_fadeout(2);
    // ...
 
    // Increase the main-volume level every 3 ticks.
    // (`0` means every ticks)
    audio_efx_amp_fadein(2);
    // ...
  }
}

Function Documentation

audio_efx_amp()

void audio_efx_amp

(

void

)

MSX The AMP effector for the libmsx audio replayer.

Calling this function each time after audio_play() will control or attenuate the main volume of all PSG, SCC/SCC+, and OPLL channels.

audio_efx_amp_set_volume()

void audio_efx_amp_set_volume

(

uint8_t

volume

)

MSX Sets the main volume level to the AMP effector.

Parameters

volume

The main volume level. (0..15)

audio_efx_amp_get_volume()

uint8_t audio_efx_amp_get_volume

(

void

)

MSX Gets the current main volume level from the AMP effector.

Returns

The current main volume level. (0..15)

audio_efx_amp_fadeout()

void audio_efx_amp_fadeout

(

uint8_t

ticks

)

MSX Decrease the main volume level by one for each specified period of time.

(Fade out)

Fade out every ticks+1 VSYNC counts.

Parameters

ticks

Period (VSYNC counts ; wait counts)

audio_efx_amp_fadein()

void audio_efx_amp_fadein

(

uint8_t

ticks

)

MSX Increase the main volume level by one for each specified period of time.

(Fade in)

Fade in every ticks+1 VSYNC counts.

Parameters

ticks

Period (VSYNC counts ; wait counts)

audio_efx_amp_get_fade()

int8_t audio_efx_amp_get_fade

(

void

)

MSX Return the status of fade-in/out.

Returns

The status of fade-in/out:

• 0 if the main volume is constant,
• negative during fade-out, and
• positive during fade-in.