BlipKit is a C library for creating the beautiful sound of old sound chips.

  • Generate waveforms: square, triangle, noise, sawtooth, sine and custom waveforms
  • Use an unlimited number of individual tracks
  • Use stereo output or up to 8 channels
  • Define instruments to create envelopes and other interesting effects
  • Use effects: portamento, tremolo, vibrato and some more
  • Load multi-channel samples and play them at different pitches

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Basic Example

Square Wave with Tremolo
Square Wave with Tremolo

This code demonstrates the basic steps to generate audio data of a square wave in the note A with enabled tremolo effect:

// Context object
BKContext ctx;

// Initialize context with 2 channels (stereo)
// and a sample rate of 44100 Hz
BKContextInit (& ctx, 2, 44100);

// Track object to generate the waveform
BKTrack track;

// Initialize track with square wave
// By default, the square wave has a duty cycle of 12.5%
BKTrackInit (& track, BK_SQUARE);

// Set mix and note volume
BKSetAttr (& track, BK_MASTER_VOLUME, 0.15 * BK_MAX_VOLUME);
BKSetAttr (& track, BK_VOLUME,        1.0 * BK_MAX_VOLUME);

// Set note A in octave 3
BKSetAttr (& track, BK_NOTE, BK_A_3 * BK_FINT20_UNIT);

// Enable tremolo effect
BKInt tremolo [2] = {20, 0.66 * BK_MAX_VOLUME};
BKTrackSetEffect (& track, BK_EFFECT_TREMOLO, tremolo, sizeof (tremolo));

// Attach track to context
BKTrackAttach (& track, & ctx);

// Define audio data buffer
// As there are 2 channels used, the buffer actually must be
// two times the size than number of frames are requested
BKFrame frames [512 * 2];

// Generate 512 frames, e.g., as they would be requested by an audio output function
// Subsequent calls to this function generate the next requested number of frames
BKContextGenerate (& ctx, frames, 512);

// The channels are interlaced into the buffer in the form: LRLR...
// Which means that the first frame of the left channel is at frames[0],
// the first frame of the right channel at frames[1] and so on