Drawing a star with n points

Hi guys I have this question to do but I have no clue for any of it.

First write a function file star.m with first line function turtle=star(turtle,npoints,R,r) which uses turtle to draw a star centred at the turtle’s current location. Inputs: • turtle: an initialized turtle to draw the star with; • npoints: the number of points the star; • R: distance from the centre of the star to the points; • r: distance from the centre to the inward corners between the points. Output turtle: turtle used for drawing in its new state. One point of the star should point in the initial direction of the turtle.

Thanks help would be appreciated.

[Ken Atwell]

Is this a homework problem? It seems like you need a "turtle" object, did your professor provide you one?

[James Connor]

yes we are given the turtle object. I just have no idea how you would go about drawing a star with n points.

[Maria Koneva]

Sounds like python

[Adam Danz]

See createStarVertices() on the file exchange where you can set

• number of rays
• center point
• inner and outer diameters
• orientation

Answer 1

[Image Analyst]

Did you search the forum: http://www.mathworks.com/matlabcentral/answers/32786-six-pointed-star

Attached are my only two star demos. You're welcome to adapt them.

[James Connor]

Hey I'm not really sure what to modify on your code to turn it into a regular star? Thanks for the help

[Image Analyst]

James, try this to draw one star. Change parameters to do whatever else you need to do with your turtle to define the location and angle of the star.

% Define parameters
numberOfPoints = 5;
rotationAngle = 0;
xCenter = 3;
yCenter = 4;
% Determine the angles that the arm tips are at
theta = (0 : (numberOfPoints-1)/numberOfPoints*pi : (numberOfPoints-1)*pi) + rotationAngle;
% Define distance from the arm tip to the center of star.
amplitude = 3;
% Get x and y coordinates of the arm tips.
x = amplitude .* cos(theta) + xCenter;
y = amplitude .* sin(theta) + yCenter;
% Draw it.
plot(x, y, 'b-', 'LineWidth', 2);
grid on;
axis square;