qmk_firmware/quantum/rgb_matrix/animations/fractal_anim.h

/* Copyright (C) 2021 @filterpaper
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

// Inspired from 4x12 fractal created by @schwarzgrau

#ifdef ENABLE_RGB_MATRIX_FRACTAL
RGB_MATRIX_EFFECT(FRACTAL)
#   ifdef RGB_MATRIX_CUSTOM_EFFECT_IMPLS

static bool FRACTAL(effect_params_t* params) {
    #define MID_COL MATRIX_COLS / 2
    static bool led[MATRIX_ROWS][MATRIX_COLS];

    static uint32_t wait_timer = 0;
    if (wait_timer > g_rgb_timer) { return false; }

    inline uint32_t interval(void) { return 3000 / scale16by8(qadd8(rgb_matrix_config.speed, 16), 16); }

    RGB rgb = rgb_matrix_hsv_to_rgb(rgb_matrix_config.hsv);
    for (uint8_t h = 0; h < MATRIX_ROWS; ++h) {

        for (uint8_t l = 0; l < MID_COL-1; ++l) {           // Light and move left columns outwards
            if (led[h][l]) { rgb_matrix_set_color(g_led_config.matrix_co[h][l], rgb.r, rgb.g, rgb.b); }
            else { rgb_matrix_set_color(g_led_config.matrix_co[h][l], 0, 0, 0); }
            led[h][l] = led[h][l+1];
        }

        for (uint8_t r = MATRIX_COLS-1; r > MID_COL; --r) { // Light and move right columns outwards
            if (led[h][r]) { rgb_matrix_set_color(g_led_config.matrix_co[h][r], rgb.r, rgb.g, rgb.b); }
            else { rgb_matrix_set_color(g_led_config.matrix_co[h][r], 0, 0, 0); }
            led[h][r] = led[h][r-1];
        }

        // Light both middle columns
        if (led[h][MID_COL]) { rgb_matrix_set_color(g_led_config.matrix_co[h][MID_COL], rgb.r, rgb.g, rgb.b); }
        else { rgb_matrix_set_color(g_led_config.matrix_co[h][MID_COL], 0, 0, 0); }
        if (led[h][MID_COL-1]) { rgb_matrix_set_color(g_led_config.matrix_co[h][MID_COL-1], rgb.r, rgb.g, rgb.b); }
        else { rgb_matrix_set_color(g_led_config.matrix_co[h][MID_COL-1], 0, 0, 0); }

        // Generate new random fractal columns
        led[h][MID_COL] = led[h][MID_COL-1] = (random8() & 3) ? false : true;
    }

    wait_timer = g_rgb_timer + interval();
    return false;
}
#   endif // RGB_MATRIX_CUSTOM_EFFECT_IMPLS
#endif    // ENABLE_RGB_MATRIX_FRACTAL