QMK/keyboards/betalupi_ergodox/animations/fft.h

#ifdef RGB_MATRIX_FRAMEBUFFER_EFFECTS
#ifndef DISABLE_RGB_MATRIX_FFT_ANIM
RGB_MATRIX_EFFECT(FFT_ANIM)

#ifdef RGB_MATRIX_CUSTOM_EFFECT_IMPLS


static int8_t fft_array_to_col[4][14] = {
	// Each number represets a bin and a height:
	// x % bin_height = height,
	// x / bin_height = bin
	//
	// Indices are [col][row].

	// Right side
	{ 29,  34,  39,  44,  49,
	  28,  33,  38,  43,  48,
	  27,  32,  37,  42},{47,
	  26,  31,  36,  41,  46,
	       30,  35,  40,  45,

	// Left side, mirrored
	   24,  19,  14,   9},{ 4,
	   23,  18,  13,   8,   3,
	   22,  17,  12,   7,   2,
	   21,  16,  11},{ 6,   1,
	   20,  15,  10,   5,   0,

	// No keys here, fill array length
	0, 0, 0, 0, 0, 0, 0}
};

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) {
	uint8_t led_min = RGB_MATRIX_LED_PROCESS_LIMIT * params->iter;
	uint8_t led_max = led_min + RGB_MATRIX_LED_PROCESS_LIMIT;
	if (led_max > sizeof(g_rgb_frame_buffer)) led_max = sizeof(g_rgb_frame_buffer);

	if (params->init) {
		rgb_matrix_set_color_all(0, 0, 0);
		memset(g_rgb_frame_buffer, 0, sizeof g_rgb_frame_buffer);
	}


	// Render heatmap & decrease
	for (int i = led_min; i < led_max; i++) {
		uint8_t row = i % MATRIX_ROWS;
		uint8_t col = i / MATRIX_ROWS;
		uint8_t val = g_rgb_frame_buffer[row][col];

		bool is_topmost = false;
		int8_t height = fft_array_to_col[col][row] % 5;
		int8_t bin = fft_array_to_col[col][row] / 5;
		if (height == 5 - 1) {
			is_topmost = true;
		} else {
			// Row and col of key above this one
			if (
				g_rgb_frame_buffer[
					fft_col_to_array[bin][height + 1] % MATRIX_ROWS
				][
					fft_col_to_array[bin][height + 1] / MATRIX_ROWS
				] == 0
			) {
				is_topmost = true;
			}
		}

		if (is_topmost) {
			rgb_matrix_set_color(i, val, 0x00, val);
		} else {
			rgb_matrix_set_color(i, 0x00, 0x00, val);
		}
	}

	return led_max < sizeof(g_rgb_frame_buffer);
}

#endif
#endif
#endif