avr/flame/main.c

#include <avr/io.h>
#include <util/delay.h>

#include <base.h>
#include <sk9822.h>

uint8_t random_step(uint8_t value, uint8_t min, uint8_t max, rng_t *rng) {
    int8_t step = (rng_sample(rng) % 32) - 16;
    uint16_t new_value = value + step;
    if (new_value > max) {
       return max;
    } else if (new_value < min) {
        return min;
    } else {
        return new_value;
    }
}

void flicker(rgb_t *pixel, rng_t *rng) {
    pixel->r = random_step(pixel->r, 180, 255, rng);
    pixel->g = random_step(pixel->g, 10, 40, rng);
}

int main (void) {
    DDRB = _BV(2) | _BV(1) | _BV(0);
    PORTB = 0;
    _delay_ms(50);

    io_pin_t data_pin = { .port = &PORTB, .pin = 0 };
    io_pin_t clock_pin = { .port = &PORTB, .pin = 2 };

    rgb_t lamps[2] = { { .brightness =  9, .r = 212, .g =  50, .b =   0 },
                       { .brightness =  1, .r =   0, .g =   0, .b =   0 } };

    int8_t step_1 = 1;
    rng_t rng = rng_new(0);
    while (1) {
        send_pixels(data_pin, clock_pin, lamps, 2);

        flicker(&lamps[0], &rng);

        lamps[1].r += step_1;

        if (lamps[1].r == 255) {
            step_1 = -1;
        } else if (lamps[1].r == 0) {
            step_1 = 1;
        }
        _delay_ms(16);
    }
}