Turtle

Turtle.m

classdef Turtle < handle
    % MATLABで簡易のTurtle Graphicsを行うためのクラス
    %
    % Turtle Properties:
    %    p - Turtleの位置を表す行ベクトル [x, y]
    %    penOnPaper - trueならTurtleの軌跡を描画する
    %
    % Turtle Methods:
    %    moveTo - Turtleを位置 pDst に移動させる
    %    penUp - Turtleが移動した軌跡を描画しない
    %    penDown - Turtleが移動した軌跡を描画する

    properties
        p
        penOnPaper
    end

    properties (Access=private)
        fig
        marker
    end

    methods
        function obj = Turtle()
            obj.fig = figure;
            xlim([-10.0, 10.0]);
            ylim([-10.0, 10.0]);
            pbaspect([1, 1, 1]);

            obj.p = [0.0, 0.0];
            obj.penOnPaper = true;

            hold on;
            obj.marker = plot(obj.p(1), obj.p(2), 'ro'); 
            hold off;
        end

        function moveTo(obj, pDst)

            figure(obj.fig);

            pSrc = obj.p;
            pDist = sqrt(sum((pSrc - pDst) .^2));
            pDist = max(3, int32(pDist));

            t = linspace(0.0, 1.0, pDist);
            for k = 1:length(t)-1
                s = (1.0 - t(k)) * pSrc + t(k) * pDst;
                e = (1.0 - t(k+1)) * pSrc + t(k+1) * pDst;
                segm = [s; e];
        
                hold on;
                if obj.penOnPaper
                    l = line(segm(:, 1), segm(:, 2));
                    l.Color = 'black';
                    l.LineWidth = 1;
                end
                obj.marker.XData = e(1);
                obj.marker.YData = e(2);
                hold off;
                drawnow();
                pause(1.0 / 100.0);
            end

            obj.p = pDst;
        end

        function penUp(obj)
            obj.penOnPaper = false;
        end

        function penDown(obj)
            obj.penOnPaper = true;
        end
    end
end