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  • drawing with ripples

on 26 Nov 2023
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drawframe(2);
Write your drawframe function below
function drawframe(f)
% set tablesize nxn (ts), output image (o), timer matrix (tm), and seed
% random number generator (rng) so randomized pebbles remain in consistent
% locations as each frame is generated
ts=100;
o=zeros(ts);
tm=o;
rng(9);
% use starting image (im) for pebble locations
imr=[12 12 12 25 25 25 37 37 37 50 50 50 50 50 50 63 63 63 75 75 75 88 88 88];
imc=[12 50 88 25 50 75 37 50 63 25 37 63 12 88 75 37 50 63 50 25 75 12 50 88];
for i1=1:numel(imr)
tm(imr(i1),imc(i1))=1;
end
% sf (scale factor) is a multiplier allowing for deeper iterations at the cost of animation
% resolution (skips frames), due to limitation of f=1:48 (48 frame per animation)
sf=1;
% loop to iterate through previous frames (1 -> f-1) to generate current frame (f)
for i1=1:sf*f
if f==1
break;
end
% pad output and timer with extra space for ripple overflow to be trimmed later
o=paddata(o,[ts+2*sf*f ts+2*sf*f],Side="both");
tm=paddata(tm,[ts+2*sf*f ts+2*sf*f],Side="both");
[rP,cP]=find(tm>0);
% core loop for evaluating locations > 0 in timer matrix (value equates to how
% many turns have lapsed since pebble dropped at this location) and drawing new ripples at
% these locations while also erasing old ripples
for i2=1:numel(rP)
t=tm(rP(i2),cP(i2));
newrip=t*ones(2*t+1);
newrip(2:end-1,2:end-1)=0;
o(rP(i2)-t:rP(i2)+t,cP(i2)-t:cP(i2)+t)=o(rP(i2)-t:rP(i2)+t,cP(i2)-t:cP(i2)+t)+newrip;
oldrip=ones(2*t-1);
o(rP(i2)-(t-1):rP(i2)+(t-1),cP(i2)-(t-1):cP(i2)+(t-1))=o(rP(i2)-(t-1):rP(i2)+(t-1),cP(i2)-(t-1):cP(i2)+(t-1))-oldrip;
tm(rP(i2),cP(i2))=t+1;
end
% trim overflow padding so output and timer both back to ts
c=size(o/2)/2;
o=o(c-ts/2:c+ts/2,c-ts/2:c+ts/2);
tm=tm(c-ts/2:c+ts/2,c-ts/2:c+ts/2);
end
o=uint16(o);
cmp=colormap(turbo(1+max(max(o))));
o=ind2rgb(o,cmp);
imshow(o)
end
Animation
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