Replicube demo Gameboy solution

gameboy.lua

-- cs: 594, c/v: 328.552
local function union(a, b)
    return function(x, y, z)
        local v = a(x, y, z)
        return (v ~= 0) and v or b(x, y, z)
    end
end

local function union_col(a, b)
    return function(x, y, z)
        local v2 = b(x, y, z)
        if v2 ~= 0 then
            return v2
        end
        return a(x, y, z)
    end
end

local function intersection(a, b)
    return function(x, y, z)
        local v = a(x, y, z)
        return (v ~= 0 and b(x, y, z) ~= 0) and v or 0
    end
end

local function subtraction(a, b)
    return function(x, y, z)
        local v = a(x, y, z)
        return (v ~= 0 and b(x, y, z) == 0) and v or 0
    end
end

local function exclusion(a, b)
    return function(x, y, z)
        local va, vb = a(x, y, z), b(x, y, z)
        if va ~= 0 and vb == 0 then return va end
        if vb ~= 0 and va == 0 then return vb end
        return 0
    end
end

function box(x1,y1,z1, x2,y2,z2, c)
  local xmin,xmax = min(x1,x2), max(x1,x2)
  local ymin,ymax = min(y1,y2), max(y1,y2)
  local zmin,zmax = min(z1,z2), max(z1,z2)
  return function(x,y,z)
    if x < xmin or x > xmax
    or y < ymin or y > ymax
    or z < zmin or z > zmax then
      return 0
    end
    return c
  end
end

function vox(xo,yo,zo,c)
	return function(x,y,z)
		return xo == x and yo == y and zo == z and c
	end
end

local case_cut = function(x,y,z)
    return (x - 4 >= y + 5 and abs(z) <= 1) and 1 or 0
end


-- base box shape
local case = box(-4,  6, -1,
             4, -6,  1, 1)
						
-- cut corner off of case
case = subtraction(case, case_cut)

-- color screen face
case = union_col(case, box(-3, 5, 1, 3, 1, 1, 2))

-- indentation on screen
case = subtraction(case, box(-2, 5, 1, 2, 1, 1, 1))

-- screen coloration
case = union_col(case, box(-2, 5, 0, 2, 1, 0, 11))

-- buttons
case = union(case, vox(3, -2, 2, 7))
case = union(case, vox(1, -3, 2, 7))

-- dpad
local dpad = function(x, y, z)
    if z ~= 2 then
        return 0
    end

    if y == -2 and x >= -3 and x <= -1 then
        return 3
    end

    if x == -2 and y >= -3 and y <= -1 then
        return 3
    end

    return 0
end

case = union(case, dpad)

-- final case
return case(x,y,z)

gameboy_small.lua

-- cs: 183, c/v: 12.814
return(z==2 and((x==3 and y==-2)or(x==1 and y==-3))and 7)or
      (z==2 and((y==-2 and x>=-3 and x<=-1)or(x==-2 and y>=-3 and y<=-1))and 3)or
      (z==0 and x>=-2 and x<=2 and y>=1 and y<=5 and 11)or
      (z==1 and x>=-3 and x<=3 and y>=1 and y<=5 and(x<-2 or x>2)and 2)or
      (x>=-4 and x<=4 and y>=-6 and y<=6 and z>=-1 and z<=1
       and not((x-4)>=y+5 and abs(z)<=1)
       and not(z==1 and x>=-2 and x<=2 and y>=1 and y<=5)and 1)or 0

gameboy_tiny.lua

-- cs: 142, c/v: 17.110
return z==2 and(((x==3 and y==-2)or(x==1 and y==-3))and 7 or((y==-2 and x>-4 and x<0)or(x==-2 and y>-4 and y<0))and 3)
   or z==0 and abs(x)<=2 and y>0 and y<6 and 11
   or z==1 and abs(x)==3 and y>0 and y<6 and 2
   or abs(x)<=4 and abs(y)<=6 and abs(z)<=1 and x<y+9 and(z<1 or abs(x)>2 or y<1 or y>5)and 1
   or 0