LightComposer

LED effects engine for embedded systems, written in C. Provides a tick-based rendering loop with smooth brightness transitions, color blending, and a library of built-in effects. Platform-agnostic — works on any target through a minimal HAL (hardware abstraction layer).

Features

• Tick-driven architecture with configurable FPS
• Smooth brightness fading and effect crossfade
• HSV/RGB/Kelvin color utilities, gradients, color correction
• Configurable LED count, color order, and pixel skip at runtime
• 15 built-in effects: static, rainbow, breathing, aurora, candlelight, comet, tide, ocean, ember, silk, heartbeat, and more

Installation

Add as a PlatformIO dependency:

[env]
lib_deps = mishamyrt/LightComposer@^2.0.0

Quick start

Implement the HAL for your LED driver:

#include <light_composer.h>

static void set_pixel(uint16_t i, rgb_t c) { /* write to your LED driver */ }
static rgb_t get_pixel(uint16_t i)          { /* read back if needed */ }
static void show(void)                      { /* flush data to the strip */ }

static const lc_hal_t hal = { set_pixel, get_pixel, show };

Initialize and run:

#define LED_COUNT 60

static rgb_t pixels[LED_COUNT];

void setup(void) {
    lc_config_t cfg = {
        .hal             = &hal,
        .pixel_buf       = pixels,
        .max_leds_count  = LED_COUNT,
        .leds_count      = LED_COUNT,
        .color_correction = LC_RGB(255, 255, 255),
        .color_order     = LC_ORDER_GRB,
        .fps             = 60,
    };
    lc_init(&cfg);

    lc_set_brightness(200);
    lc_set_power(true);
    lc_set_color(LC_RGB(255, 80, 0));
    lc_set_effect(&lc_fx_static);
}

void loop(void) {
    lc_tick();
}

Switch effects at any time — the engine will crossfade automatically:

lc_set_effect(&lc_fx_breathing);

Custom effects

Define a new effect by implementing render, activate, and color_update callbacks:

typedef struct { /* per-effect state */ } my_ctx_t;

static bool my_render(lc_state_t *s, void *raw) {
    my_ctx_t *c = (my_ctx_t *)raw;
    lc_fill(s, s->target_color);
    return true; // true = pixels changed, flush needed
}

static void my_activate(lc_state_t *s, void *raw)      { /* init state */ }
static void my_color_update(lc_state_t *s, void *raw)   { /* handle color change */ }

LC_EFFECT_DEFINE(my, LC_EFFECT_FLAG_NONE, my_ctx_t);

// then use it:
lc_set_effect(&lc_fx_my);

License

MIT