Some squishy balls
Lua Carousel » Devlog
Last night I encountered the work of Karsten Schmidt, and was inspired to reimplement a tiny part of the merest superficial sample of his huge project. It doesn't actually implement any flocking dynamics yet, and I'm also not implementing Karsten's tasteful color gradients. To my surprise, it's quite snappy even on a large screen to quadratically scan all balls for each ball's neighbors.
function normalize(p) local m = math.sqrt(p.x^2 + p.y^2) return {x=p.x/m, y=p.y/m} end -- create a vector with a random orientation function randoriented() local n = 100 return {x=rand(-n,n)/n, y=rand(-n,n)/n} end function randNorm2() return normalize(randoriented()) end PAD = 10 function randpoint() return {x=rand(PAD, Safe_width-PAD), y=rand(PAD, Safe_width-PAD)} end function norm(x, a, b) if a == b then return 0 end return (x-a)/(b-a) end function clamp01(x) return max(0, min(1, x)) end function fitClamped(x, a, b, c, d) return c + (d-c)*clamp01(norm(x, a, b)) end NUM = fitClamped(Safe_width*Safe_height, 640*480, 1440*810, 500, 1000) boids = {} for i=1,NUM do table.insert(boids, {pos=randpoint(), vel=randNorm2(), color={rand(), rand(), rand()}}) end MAX_RADIUS = 50 function neighbors(boid, d) local result = {} for i,b in ipairs(boids) do if dist2(boid.pos, b.pos) < d^2 then table.insert(result, i) end end return result end function car.update(dt) for i,b in ipairs(boids) do b.pos.x = b.pos.x + dt*b.vel.x*10 b.pos.y = b.pos.y + dt*b.vel.y*10 end for s,b in ipairs(boids) do b.d = MAX_RADIUS local neighbors = neighbors(b, MAX_RADIUS) local minD, closest for _,n in ipairs(neighbors, b.radius) do if n ~= s then local d = dist2(b.pos, boids[n].pos) if minD == nil or d < minD then closest = n minD = d end end end if minD then b.d = math.sqrt(minD) end end end function car.draw() for _,b in ipairs(boids) do color(unpack(b.color)) circle('fill', b.pos.x, b.pos.y, b.d/2) end end function dist2(a, b) return (a.x-b.x)^2 + (a.y-b.y)^2 end
If you try pasting any of these programs 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 circle = g.circle color = g.setColor min, max = math.min, math.max rand = math.random
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Lua Carousel
Write programs on desktop and mobile
Status | In development |
Category | Tool |
Author | Kartik Agaram |
Tags | LÖVE |
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