Pixel-Composer/scripts/node_posterize/node_posterize.gml

function Node_Posterize(_x, _y, _group = noone) : Node_Processor(_x, _y, _group) constructor {
	name = "Posterize";
	
	inputs[0] = nodeValue_Surface("Surface in", self);
	
	inputs[1] = nodeValue_Palette("Palette", self, array_clone(DEF_PALETTE));
	
	inputs[2] = nodeValue_Bool("Use palette", self, true);
	
	inputs[3] = nodeValue_Int("Steps", self, 4)
		.setDisplay(VALUE_DISPLAY.slider, { range: [2, 16, 0.1] });
	
	inputs[4] = nodeValue_Float("Gamma", self, 1)
		.setDisplay(VALUE_DISPLAY.slider, { range: [0, 2, 0.01] })
		.setMappable(7);
	
	inputs[5] = nodeValue_Bool("Active", self, true);
		active_index = 5;
		
	inputs[6] = nodeValue_Bool("Posterize alpha", self, true);
	
	//////////////////////////////////////////////////////////////////////////////////////////////////
	
	inputs[7] = nodeValueMap("Gamma map", self);
	
	//////////////////////////////////////////////////////////////////////////////////////////////////
	
	inputs[8] = nodeValue_Enum_Button("Space", self,  0, [ "RGB", "LAB" ]);
	
	input_display_list = [ 5, 0, 
		["Palette", false, 2], 1, 3, 4, 7, 8, 
		["Alpha",   false], 6, 
	];
	
	outputs[0] = nodeValue_Output("Surface out", self, VALUE_TYPE.surface, noone);
	
	attribute_surface_depth();
	
	temp_surface = [ surface_create(1, 1), surface_create(1, 1), surface_create(1, 1), surface_create(1, 1) ];
	
	static step = function() {
		var _use_pal = getInputData(2);
		
		inputs[1].setVisible(_use_pal);
		inputs[3].setVisible(!_use_pal);
		inputs[4].setVisible(!_use_pal);
		inputs[4].mappableStep();
		inputs[8].setVisible(_use_pal);
	}
	
	static processData = function(_outSurf, _data, _output_index, _array_index) {
		var _surf    = _data[0];
		var _pal     = _data[1];
		var _use_pal = _data[2];
		var _alp     = _data[6];
		var _spce    = _data[8];
		
		if(_use_pal) {
			surface_set_shader(_outSurf, sh_posterize_palette);
				shader_set_palette(_pal, "palette", "keys");
				shader_set_i("alpha", _alp);
				shader_set_i("space", _spce);
				
				draw_surface_safe(_surf);
			surface_reset_shader();
			
		} else {
			#region get range
				var _sw  = surface_get_width(_surf);
				var _sh  = surface_get_height(_surf);
				var _itr = ceil(logn(4, _sw * _sh / 1024));
				
				var _sww = ceil(_sw / 2);
				var _shh = ceil(_sh / 2);
				
				for (var i = 0, n = array_length(temp_surface); i < n; i++) 
					temp_surface[i] = surface_verify(temp_surface[i], _sw, _sh);
				
				surface_set_shader(temp_surface[0]);
					draw_surface_safe(_surf);
				surface_reset_shader();
				
				surface_set_shader(temp_surface[1]);
					draw_surface_safe(_surf);
				surface_reset_shader();
				
				surface_clear(temp_surface[2]);
				surface_clear(temp_surface[3]);
				
				var _ind = 1;
				repeat(_itr) {
					surface_resize(temp_surface[(_ind) * 2 + 0], _sww, _shh);
					surface_resize(temp_surface[(_ind) * 2 + 1], _sww, _shh);
					
					shader_set(sh_get_max_downsampled);
					surface_set_target_ext(0, temp_surface[(_ind) * 2 + 0]);
					surface_set_target_ext(1, temp_surface[(_ind) * 2 + 1]);
						shader_set_f("dimension", _sww, _shh);
						shader_set_surface("surfaceMax", temp_surface[(!_ind) * 2 + 0]);
						shader_set_surface("surfaceMin", temp_surface[(!_ind) * 2 + 1]);
						
						draw_sprite_stretched(s_fx_pixel, 0, 0, 0, _sww, _shh);
					surface_reset_target();
					shader_reset();
					
					_sww = ceil(_sww / 2);
					_shh = ceil(_shh / 2);
					
					_ind = !_ind;
				}
				
				var _sMax = temp_surface[(!_ind) * 2 + 0];
				var _sMin = temp_surface[(!_ind) * 2 + 1];
				var _ssw  = surface_get_width(_sMax);
				var _ssh  = surface_get_height(_sMax);
				var _max  = [ 0, 0, 0 ];
				var _min  = [ 1, 1, 1 ];
				
				var _bMax = buffer_from_surface(_sMax, false);
				var _bMin = buffer_from_surface(_sMin, false);
				
				buffer_to_start(_bMax);
				buffer_to_start(_bMin);
				
					repeat(_ssw * _ssh) {
						var _cc = buffer_read(_bMax, buffer_u32);
						_max[0] = max(_max[0], _color_get_red(_cc));
						_max[1] = max(_max[1], _color_get_green(_cc));
						_max[2] = max(_max[2], _color_get_blue(_cc));
						
						var _cc = buffer_read(_bMin, buffer_u32);
						_min[0] = min(_min[0], _color_get_red(_cc));
						_min[1] = min(_min[1], _color_get_green(_cc));
						_min[2] = min(_min[2], _color_get_blue(_cc));
						
					}
					
				buffer_delete(_bMax);
				buffer_delete(_bMin);
			#endregion
			
			surface_set_shader(_outSurf, sh_posterize);
				shader_set_f("cMax",       _max);
				shader_set_f("cMin",       _min);
				shader_set_f("colors",    _data[3]);
				shader_set_f_map("gamma", _data[4], _data[7], inputs[4]);
				shader_set_i("alpha",     _alp);
			
				draw_surface_safe(_surf);
			surface_reset_shader();
		}
		
		return _outSurf;
	}
}