how to avoid overlapping when drawing dots using screen function?

Question

Jinyi Tao 2016-2-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/267364-how-to-avoid-overlapping-when-drawing-dots-using-screen-function

回答： sam0037 2016-2-15

I am a beginner in Matlab and Psychtoolbox. I want to plot random number of dots between 1 to 10, but I don't know how to avoid the overlapping. These are my codes:

        n = randi([1 8]); n(n==5) = 9;    
        DataBase=[]; 
        DataBase = [DataBase, n];
        dots.nDots = Shuffle(DataBase);
        dots.col = black;
        dots.size = 30;
        dots.center = [960, 540];
        dots.apertureSize = [900, 900];
        dots.x = (rand(1,dots.nDots)-.5)*dots.apertureSize(1) + dots.center(1);
        dots.y = (rand(1,dots.nDots)-.5)*dots.apertureSize(2) + dots.center(2);
        Screen('DrawDots', mainwin, [dots.x;dots.y], dots.size, dots.col, [0, 0], 2);

Thank you for helping!!

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Jan 2016-2-9

在 MATLAB Online 中打开

The start of teh code ist strange. dots.nDots is a scalar from the set [1:4, 6:9]. Neither the concatenation nor the shuffeling is meaningful. Shorter:

dots.nDots = randi([1, 8]);
if dots.nDots == 5
  dots.nDots = 9;
end

But then I do not see the connection to the description: "random number of dots between 1 to 10".

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

sam0037 2016-2-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/267364-how-to-avoid-overlapping-when-drawing-dots-using-screen-function#answer_209851

Hi Jinyi,

I do not have a Psychtoolbox installed currently and hence cannot reproduce this issue. But from the above code, I understand that when you plot a set of dots of certain size(size of all dots are fixed in this case), some of them overlap which you would like to avoid. Two dots say D1 and D2 will overlap only when radius(D1)+radius(D2)<=distance between centers of D1 and D2. I hope this helps in redesigning the algorithm to suit your use case. If this is not what you were looking for, please elaborate on the use-case.

Thanks, Shamim