Pixel-Composer/scripts/node_audio_loudness/node_audio_loudness.gml

function Node_Audio_Loudness(_x, _y, _group = noone) : Node_Processor(_x, _y, _group) constructor {
	name = "Audio Loudness";
	setDimension(96, 72);
	
	inputs[0] = nodeValue_Float("Audio Data", self, [])
		.setArrayDepth(1)
		.setVisible(true, true);
	
	outputs[0] = nodeValue_Output("Loudness", self, VALUE_TYPE.float, 0);
	
	static processData = function(_outSurf, _data, _output_index, _array_index) {
		var _dat = _data[0];
		
		var N    = array_length(_dat);
		var val  = 0;
		if(N == 0) return 0;
		
		for( var i = 0; i < N; i++ )
			val += _dat[i] * _dat[i];
		val = sqrt(val / N);
		
		var dec = 10 * log10(val);
		return dec;
	}
	
	static onDrawNode = function(xx, yy, _mx, _my, _s, _hover, _focus) {
		var bbox = drawGetBbox(xx, yy, _s);
		draw_sprite_fit(s_node_audio_volume, 0, bbox.xc, bbox.yc, bbox.w, bbox.h);
	}
}