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Playing sounds

This guide will help you understand how to play sounds.

Waveforms​

RIV can playing simple audio waveforms through the function riv_waveform, using the riv_waveform_desc structure as argument, which has the following fields:

  • type - Waveform type
  • delay - Start delay in seconds
  • attack - Attack duration in seconds
  • decay - Decay duration in seconds
  • sustain - Sustain duration in seconds
  • release - Release duration in seconds
  • start_frequency - Starting frequency in Hz
  • end_frequency - Starting frequency in Hz
  • amplitude - Maximum amplitude in range (0.0, 1.0]
  • sustain_level - Sustain level in range (0.0, 1.0]
  • duty_cycle - Duty cycle in range (0.0, 1.0]
  • pan - Pan in range [-1.0, 1.0]

Where type can be one of:

  • RIV_WAVEFORM_SINE - Sine wave
  • RIV_WAVEFORM_SQUARE - Square wave
  • RIV_WAVEFORM_TRIANGLE - Triangle wave
  • RIV_WAVEFORM_SAWTOOTH - Sawtooth wave
  • RIV_WAVEFORM_NOISE - Noise wave
  • RIV_WAVEFORM_PULSE - Pulse wave

You can define a sound effect configuration and play during an event like this:

// Shoot sound configuration
riv_waveform_desc shoot_sfx = {
    .type = RIV_WAVEFORM_PULSE,
    .attack = 0.050, .decay = 0.050, .sustain = 0.150, .release = 0.075,
    .start_frequency = 880, .end_frequency = 220,
    .amplitude = 0.15, .sustain_level = 0.25,
    .duty_cycle = 0.65, .pan = 0.0,
};
// Play the sound
riv_waveform(&shoot_sfx);

Waveform editor​

The following is a tool to help you find new waveform configurations, the idea is to discover new sounds and its parameters with the tool, to later copy them into your game.

You can view the code for this example at waveform.c.

For example, the JUMP preset can be replicated with:

riv_waveform_desc jump_sfx = {
    .type = RIV_WAVEFORM_TRIANGLE,
    .attack = 0.025, .decay = 0.1, .sustain = 0.075, .release = 0.025,
    .start_frequency = 327, .end_frequency = 702,
    .amplitude = 0.25, .sustain_level = 0.05,
    .duty_cycle = 0.5, .pan = 0.0,
};
riv_waveform(&jump_sfx);