1 files changed, 75 insertions, 0 deletions
diff --git a/quantum/rgb_matrix/animations/digital_rain_anim.h b/quantum/rgb_matrix/animations/digital_rain_anim.h
new file mode 100644
index 0000000000..1de45f8e8d
--- /dev/null
+++ b/quantum/rgb_matrix/animations/digital_rain_anim.h
@@ -0,0 +1,75 @@
+#if defined(RGB_MATRIX_FRAMEBUFFER_EFFECTS) && !defined(DISABLE_RGB_MATRIX_DIGITAL_RAIN)
+RGB_MATRIX_EFFECT(DIGITAL_RAIN)
+#    ifdef RGB_MATRIX_CUSTOM_EFFECT_IMPLS
+
+#        ifndef RGB_DIGITAL_RAIN_DROPS
+// lower the number for denser effect/wider keyboard
+#            define RGB_DIGITAL_RAIN_DROPS 24
+#        endif
+
+bool DIGITAL_RAIN(effect_params_t* params) {
+    // algorithm ported from https://github.com/tremby/Kaleidoscope-LEDEffect-DigitalRain
+    const uint8_t drop_ticks           = 28;
+    const uint8_t pure_green_intensity = 0xd0;
+    const uint8_t max_brightness_boost = 0xc0;
+    const uint8_t max_intensity        = 0xff;
+
+    static uint8_t drop = 0;
+
+    if (params->init) {
+        rgb_matrix_set_color_all(0, 0, 0);
+        memset(g_rgb_frame_buffer, 0, sizeof(g_rgb_frame_buffer));
+        drop = 0;
+    }
+
+    for (uint8_t col = 0; col < MATRIX_COLS; col++) {
+        for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+            if (row == 0 && drop == 0 && rand() < RAND_MAX / RGB_DIGITAL_RAIN_DROPS) {
+                // top row, pixels have just fallen and we're
+                // making a new rain drop in this column
+                g_rgb_frame_buffer[row][col] = max_intensity;
+            } else if (g_rgb_frame_buffer[row][col] > 0 && g_rgb_frame_buffer[row][col] < max_intensity) {
+                // neither fully bright nor dark, decay it
+                g_rgb_frame_buffer[row][col]--;
+            }
+            // set the pixel colour
+            uint8_t led[LED_HITS_TO_REMEMBER];
+            uint8_t led_count = rgb_matrix_map_row_column_to_led(row, col, led);
+
+            // TODO: multiple leds are supported mapped to the same row/column
+            if (led_count > 0) {
+                if (g_rgb_frame_buffer[row][col] > pure_green_intensity) {
+                    const uint8_t boost = (uint8_t)((uint16_t)max_brightness_boost * (g_rgb_frame_buffer[row][col] - pure_green_intensity) / (max_intensity - pure_green_intensity));
+                    rgb_matrix_set_color(led[0], boost, max_intensity, boost);
+                } else {
+                    const uint8_t green = (uint8_t)((uint16_t)max_intensity * g_rgb_frame_buffer[row][col] / pure_green_intensity);
+                    rgb_matrix_set_color(led[0], 0, green, 0);
+                }
+            }
+        }
+    }
+
+    if (++drop > drop_ticks) {
+        // reset drop timer
+        drop = 0;
+        for (uint8_t row = MATRIX_ROWS - 1; row > 0; row--) {
+            for (uint8_t col = 0; col < MATRIX_COLS; col++) {
+                // if ths is on the bottom row and bright allow decay
+                if (row == MATRIX_ROWS - 1 && g_rgb_frame_buffer[row][col] == max_intensity) {
+                    g_rgb_frame_buffer[row][col]--;
+                }
+                // check if the pixel above is bright
+                if (g_rgb_frame_buffer[row - 1][col] == max_intensity) {
+                    // allow old bright pixel to decay
+                    g_rgb_frame_buffer[row - 1][col]--;
+                    // make this pixel bright
+                    g_rgb_frame_buffer[row][col] = max_intensity;
+                }
+            }
+        }
+    }
+    return false;
+}
+
+#    endif  // RGB_MATRIX_CUSTOM_EFFECT_IMPLS
+#endif      // defined(RGB_MATRIX_FRAMEBUFFER_EFFECTS) && !defined(DISABLE_RGB_MATRIX_DIGITAL_RAIN)