Shekere

shekere is a real-time shader art framework that combines WGSL shaders with sound input. It supports mouse interaction, OSC control (TidalCycles, etc.), and audio spectrum analysis.

Features

🎨 Shader Support

• Fragment Shaders: Real-time WGSL fragment shader execution
• Multi-pass Rendering: Complex effects with multiple rendering passes
  • Sequential Passes: Chain multiple shaders for layered effects
  • Ping-pong Buffers: Double-buffered textures for iterative algorithms
  • Persistent Textures: State preservation across frames
• Hot Reload: Live shader editing with automatic recompilation

🎵 Audio Integration

• Spectrum Analysis: Real-time FFT analysis of audio input
• OSC Support: Integration with TidalCycles and other OSC sources
• MIDI Control: Real-time MIDI input for interactive control
  • Current Values: Access current MIDI notes, controls, and note-on events
  • Historical Data: 512-frame history buffer for time-based effects
  • Advanced Effects: Fadeout, echo, trend analysis without multi-pass rendering

🛠️ Development

• TOML Configuration: Simple, human-readable project configuration
• Built-in Uniforms: Time, window, mouse, audio data automatically available
• Helper Functions: Color space conversion, coordinate helpers, audio accessors

Installation

Install from Cargo

cargo install shekere

Download Binary

Download binaries from Releases.

Basic Usage

shekere <config_file>

Example:

shekere examples/basic/basic.toml

Getting Started

1. Create a TOML config file with window settings and shader path
2. Write a fragment shader using the built-in uniforms and helpers
3. Run with shekere config.toml

MIDI History Features

Shekere v0.11.0 introduces powerful MIDI history functionality that enables sophisticated time-based effects without multi-pass rendering:

// Current MIDI values (compatible with previous versions)
let current_note = MidiNote(60u);        // Current Middle C velocity
let current_cc = MidiControl(7u);        // Current volume CC
let attack = MidiNoteOn(60u);            // Note attack detection

// New: Historical MIDI values
let past_note = MidiNoteHistory(60u, 10u);    // Middle C from 10 frames ago
let smooth_cc = MidiControlHistory(7u, 5u);   // Volume CC from 5 frames ago
let old_attack = MidiNoteOnHistory(60u, 20u); // Note attack from 20 frames ago

// Create fadeout effects with exponential decay
fn create_fadeout(note: u32) -> f32 {
    var intensity = 0.0;
    for (var h = 0u; h < 30u; h++) {
        let history_value = MidiNoteHistory(note, h);
        let decay = exp(-f32(h) * 0.1);
        intensity += history_value * decay;
    }
    return intensity / 30.0;
}

Key Features:

• 512-frame history buffer with automatic bounds checking
• Zero-cost current access using history = 0
• Backward compatible with existing MIDI functions
• Memory efficient 768KB storage buffer design

Documentation

For detailed documentation, see:

• Development Guide - Configuration, shader development, and examples
• API Reference - Complete reference for uniforms and helper functions

Sample Projects

The included examples directory contains the following samples:

Basic Examples

• examples/basic/: Basic time-based animation
• examples/circular/: Circular pattern with concentric rings
• examples/mouse/: Mouse-controlled shader art

Audio Integration

• examples/spectrum/: Audio spectrum analysis visualizer
• examples/osc/: TidalCycles integration shader art
• examples/midi/: MIDI-controlled shader art
• examples/midi_history/: MIDI history effects (fadeout, echo, time series analysis)

Advanced Multi-pass Shaders

• examples/multi_pass/: Multi-pass rendering with blur effects
• examples/persistent/: Persistent texture effects and trail rendering
• examples/ping_pong/: Ping-pong buffer simulation and kaleidoscope effects

Use these as reference to create your own shader art projects.