Visualizing the digits of π
Lua Carousel » Devlog
The following program lets you scrub the mouse downward to find more and more precise approximations of π within the red optical sight in the center of the screen.
N = 100 -- spacing between zoom levels M = N*2 -- spacing between ticks on a single zoom level; enough space to write the tick value to some max precision y = N -- current zoom level Pan = nil -- 14159265358979323846264338327950288419716939937510 Pi = {3, 3.1, 3.14, 3.141, 3.1415, 3.14159, 3.141592, 3.1415926, 3.14159265, 3.141592653, 3.1415926535} -- the current approximation of pi function approx() local yint = floor(y/N) local yfrac = y - yint*N local lo = Pi[yint] if yint == #Pi then return lo end local hi = Pi[yint+1] return lo + yfrac/N*(hi-lo) end -- viewport location of number x assuming number 'center' is always at Safe_width/2 function vx(center, scale, x) return Safe_width/2 + (x-center)/scale * M end -- number at viewport location vx assuming number 'center' is always at Safe_width/2 function sx(center, scale, vx) return center + (vx - Safe_width/2)/M * scale end function draw_tick(center, scale, x, ly) local vx = vx(center, scale, x) line(vx, ly, vx, ly+5) g.print(x, vx, ly+10) end function ticks(level, pi) local scale = 10^-(level-1) local sxmin = sx(pi, scale, 0) local sxmax = sx(pi, scale, Safe_width) local ticklo, tickhi = Pi[level], Pi[level] if ticklo > sxmin then local k = floor((Pi[level]-sxmin)/scale) ticklo = Pi[level]-k*scale else local k = floor((sxmin-Pi[level])/scale) ticklo = Pi[level]+k*scale end if tickhi > sxmax then local k = floor((Pi[level]-sxmax)/scale) tickhi = Pi[level]-k*scale else local k = floor((sxmax-Pi[level])/scale) tickhi = Pi[level]+k*scale end assert(ticklo < tickhi) return ticklo, tickhi, scale end function car.draw() -- optical sight color(1,0,0) line(Safe_width/2, Safe_height/2-80, Safe_width/2, Safe_height/2-10) line(Safe_width/2, Safe_height/2+80, Safe_width/2, Safe_height/2+10) -- number lines local level = floor(y/N) local pi = approx() for j=1,#Pi do color(0.4,0.4,0.4) local ly = Safe_height/2 - y + j*N line(0, ly, Safe_width, ly) local ticklo, tickhi, scale = ticks(j, pi) for tick=ticklo,tickhi,scale do draw_tick(pi, scale, tick, ly) end color(0.5,0.5,1) circle('fill', vx(pi, scale, Pi[j]), ly, 5) color(0.2,0.2,1) circle('line', vx(pi, scale, Pi[j]), ly, 5) end end function car.mousepressed() Pan = true end function car.mousereleased() Pan = nil end function car.mousemoved(_x,_y,_dx, dy, ...) if not Pan then return end y = y-dy y = max(y, N) y = min(y, #Pi * N) end
If you try pasting this program into Lua Carousel, remember to first run the abbreviations on one of the example screens. Or if you've deleted that screen, here are the abbreviations I used in this post:
g = love.graphics line, circle = g.line, g.circle color = g.setColor min, max = math.min, math.max floor, ceil = math.floor, math.ceil
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Lua Carousel
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Status | In development |
Category | Tool |
Author | Kartik Agaram |
Tags | LÖVE |
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