Pixel-Composer/scripts/node_edge_detect/node_edge_detect.gml

function Node_Edge_Detect(_x, _y, _group = -1) : Node_Processor(_x, _y, _group) constructor {
	name = "Edge Detect";
	
	shader = sh_edge_detect;
	uniform_dim    = shader_get_uniform(shader, "dimension");
	uniform_filter = shader_get_uniform(shader, "filter");
	uniform_sam    = shader_get_uniform(shader, "sampleMode");
	
	inputs[| 0] = nodeValue(0, "Surface in",	 self, JUNCTION_CONNECT.input, VALUE_TYPE.surface, 0);
	inputs[| 1] = nodeValue(1, "Algorithm",		 self, JUNCTION_CONNECT.input, VALUE_TYPE.integer, 0)
		.setDisplay(VALUE_DISPLAY.enum_scroll, ["Sobel", "Prewitt", "Laplacian"] );
	
	inputs[| 2] = nodeValue(2, "Oversample mode", self, JUNCTION_CONNECT.input, VALUE_TYPE.integer, 0, "How to deal with pixel outside the surface.\n    - Empty: Use empty pixel\n    - Clamp: Repeat edge pixel\n    - Repeat: Repeat texture.")
		.setDisplay(VALUE_DISPLAY.enum_scroll, [ "Empty", "Clamp", "Repeat" ]);
	
	outputs[| 0] = nodeValue(0, "Surface out", self, JUNCTION_CONNECT.output, VALUE_TYPE.surface, PIXEL_SURFACE);
	
	input_display_list = [ 
		["Surface",		false],	0, 2, 
		["Edge detect",	false],	1, 
	];
	
	static process_data = function(_outSurf, _data, _output_index, _array_index) {
		var ft = _data[1];
		var ov = _data[2];
		
		surface_set_target(_outSurf);
		draw_clear_alpha(0, 0);
		BLEND_OVERRIDE
		
		shader_set(shader);
			shader_set_uniform_f_array(uniform_dim, [surface_get_width(_data[0]), surface_get_height(_data[0])]);
			shader_set_uniform_i(uniform_filter, ft);
			shader_set_uniform_i(uniform_sam, ov);
			draw_surface_safe(_data[0], 0, 0);
		shader_reset();
		
		BLEND_NORMAL
		surface_reset_target();
		
		return _outSurf;
	}
}