Add Fractal RGB matrix effects (#12670)

* Squashed fractal effect commit for easier rebase

* Update documentation

* Squashed fractal effect commit for easier rebase

* Update documentation

* Update doc spacing

Co-authored-by: Ryan <fauxpark@gmail.com>

* Update feature_rgb_matrix.md

Co-authored-by: filterpaper <filterpaper@localhost>
Co-authored-by: Ryan <fauxpark@gmail.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>

2 files changed, 62 insertions, 0 deletions

diff --git a/quantum/rgb_matrix/animations/fractal_anim.h b/quantum/rgb_matrix/animations/fractal_anim.h
new file mode 100644
index 0000000000..99693165d7
--- /dev/null
+++ b/quantum/rgb_matrix/animations/fractal_anim.h
@@ -0,0 +1,61 @@
+/* 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
diff --git a/quantum/rgb_matrix/animations/rgb_matrix_effects.inc b/quantum/rgb_matrix/animations/rgb_matrix_effects.inc
index 302ad79c04..33d2b42286 100644
--- a/quantum/rgb_matrix/animations/rgb_matrix_effects.inc
+++ b/quantum/rgb_matrix/animations/rgb_matrix_effects.inc
@@ -26,6 +26,7 @@
 #include "hue_breathing_anim.h"
 #include "hue_pendulum_anim.h"
 #include "hue_wave_anim.h"
+#include "fractal_anim.h"
 #include "typing_heatmap_anim.h"
 #include "digital_rain_anim.h"
 #include "solid_reactive_simple_anim.h"