N Sided Figures

[mirhagk]

I was working on a few ideas for a game roughly based on Flatland (the book). It is a two dimensional world, and I would set the game as playing as a sort of god-like figure that would control the little shapes.

In order to do this I would need to draw shapes of any type. I came up with a few ideas, the worst of which was switching between different functions for each shape, or even using pictures.

Then I remembered, in Flatland the highest level shape was the one closest to a circle, so I started with a circle. If I took two points on that circle and connected them, I'd get a line. If I took 3, I'd get a triangle. 4 would be a square, and n would be a n-sided shape. The method accepts 5 arguments. The first two are the x and y of the CENTER of the shape. The third is the number of sides it has. The fourth is the radius of the circle it draws points from, which controls the size of the figure. The last argument is used to rotate the figure by any angle (rotations are around the center in a counter-clockwise direction)

So what you may ask? Well haven't you ever wanted to maybe draw a triangle, or a pentagon, but didn't want to have to define every point. Or maybe you wanted to draw a square, but with the ability for it to rotate. Well now you can, and here is my code. If anyone has some suggestions for performance boosts, I'm open to them (I'm thinking of a system right now that will not need an array, only the first point and the current point need to be stored)

Turing:

proc DrawNSidedShape (x, y, n, r, rot : int) %x and y position, number of sides, radius, rotation     var disx, disy : real %the distance from the center to the current point     var angle : real %the angle around the circle     var pointsx : array 1 .. n of int %arrays to store the points     var pointsy : array 1 .. n of int     for i : 1 .. n %%for every side         angle := 360 / n * (i - 1) + 90 + rot %the angle is 360/number of sides*what side it is         %I subtract one so it starts at 0, add the rotation and 90         %which just centers it at the top         disx := cosd (angle) * r %calculate the distance in x cosine of angle * radius         disy := sind (angle) * r %same as above except with y and sine         pointsx (i) := x + round (disx) %add this to the list of points         pointsy (i) := y + round (disy)     end for     for i : 1 .. n - 1 %for every point except the last         %draw a point connecting it to the nect one         drawline (pointsx (i), pointsy (i), pointsx (i + 1), pointsy (i + 1), black)     end for     %connect the last one to the first one     drawline (pointsx (1), pointsy (1), pointsx (n), pointsy (n), black)     %colours may be changed, this last line simply fills it with green     drawfill (x, y, brightgreen, black) end DrawNSidedShape var win : int := Window.Open ("position:left;top") loop     var numSides : int     get numSides     exit when numSides = 0     DrawNSidedShape (maxx div 2, maxy div 2, numSides, maxy div 2, 0)     Input.Pause     drawoval (maxx div 2, maxy div 2, maxy div 2, maxy div 2, black)     Input.Pause     cls end loop Window.Close (win)

[DemonWasp]

Not a bad implementation (specifically, the method signature is well-done), but you should be able to figure out a way to do this without using arrays. Doing so will improve the performance of your drawing algorithm, letting you draw more complex scenes.

You probably also want a parameter for draw-colour.

[mirhagk]

Or would it be faster to leave the array and call draw polygon, it would severly decrease the amount of drawing calls.