QMK/animations/fft.h

#ifdef RGB_MATRIX_DATAPOINTER_ENABLED
#ifndef DISABLE_RGB_MATRIX_FFT_ANIM
RGB_MATRIX_EFFECT(FFT_ANIM)

#ifdef RGB_MATRIX_CUSTOM_EFFECT_IMPLS

// Maps fft columns to leds.
// fft_col_to_array[i] returns an array of leds in the ith bin of the fft.
// Negative indices are "invisible" leds.
// Use them when your keyboard has gaps.
//
// This layout is for the Ergodox EZ.
static int8_t fft_col_to_array[10][5] = {
	{ 47, 43, 38, 33, 28 },
	{ 46, 42, 37, 32, 27 },
	{ 45, 41, 36, 31, 26 },
	{ 44, 40, 35, 30, 25 },
	{ -1, 39, 34, 29, 24 },
	{ -1, 15, 10,  5,  0 },
	{ 20, 16, 11,  6,  1 },
	{ 21, 17, 12,  7,  2 },
	{ 22, 18, 13,  8,  3 },
	{ 23, 19, 14,  9,  4 }
};


// TODO:
// Dynamic color settings
bool FFT_ANIM(effect_params_t* params) {
	RGB_MATRIX_USE_LIMITS(led_min, led_max);

	// REQUIRED for any animation that uses this pointer.
	// Clears any previous data.
	if (params->init) {
		rgb_matrix_anim_data = NULL;
		return led_max < DRIVER_LED_TOTAL;
	};

	if (rgb_matrix_anim_data == NULL) {
		// If animation data is empty, turn off all leds and exit.
		for (uint8_t i = led_min; i < led_max; i++) {
			rgb_matrix_set_color(
				i,
				0x00, 0x00, 0x00
			);
		}
	} else {

		// Data should be a pointer to 10 uint8_ts, each representing
		// the height of a bar on the display.
		uint8_t* data = (uint8_t*) rgb_matrix_anim_data;

		for (uint8_t bin = 0; bin < 10; bin++) {
			// Scale data values
			uint8_t d = data[bin];
			uint8_t bin_height = d / 50;
			// Brightness of topmost key
			uint8_t last_brightness = ((d % 50)/50.0) * 0xFF;


			// Turn off leds that should be off.
			// There are 5 keys in each column.
			for (uint8_t i = bin_height; i < 6; i++) {
				// Ignore negative indices.
				// See fft_col_to_array definition.
				if (fft_col_to_array[bin][i] < 0) {
					continue;
				}

				rgb_matrix_set_color(
					fft_col_to_array[bin][i],
					0x00, 0x00, 0x00
				);
			}


			// Turn on leds that should be on.
			for (uint8_t i = 0; i < bin_height; i++) {
				// Ignore negative indices.
				// See fft_col_to_array definition.
				if (fft_col_to_array[bin][i] < 0) {
					continue;
				}

				// If this is the topmost lit key, its
				// brightness depends on the height of the bar.
				if (i == bin_height - 1) {
					rgb_matrix_set_color(
						fft_col_to_array[bin][i],
						last_brightness, 0x00, last_brightness
					);

				// If this isn't the topmost key,
				// it has a plain full-brightness color.
				} else {
					rgb_matrix_set_color(
						fft_col_to_array[bin][i],
						0x00, 0x00, 0xFF
					);
				}
			}
		}
	}

	return led_max < DRIVER_LED_TOTAL;
}

#endif
#endif
#endif