Text genertion of a sphere

textSphere.lua

-- code from http://rosettacode.org/wiki/Draw_a_sphere
-- tickled slightly for Codea by Bri_G
-- various authors under GNU Free Documentation Licence 1.2
-- http://www.gnu.org/licenses/fdl-1.2.html
-- Use this function to perform your initial setup

saveProjectInfo("Description", "Text Sphere")
saveProjectInfo("Version", "1.001 beta")
saveProjectInfo("Author", "Bri_G")

function setup()
    displayMode(FULLSCREEN)
    shades = {'.', ':', '!', '*', 'o', 'e', '&', '#', '%', '@'}
    light = normalize{30, 30, -50}   
end

-- This function gets called once every frame
function draw()
    -- This sets a dark background color 
    background(0, 0, 0, 255)
    -- Do your drawing here
    draw_sphere (20, 4, 0.1)
    -- draw_sphere (10, 2, 0.4)  
end

 
function normalize (vec)
    len = math.sqrt(vec[1]^2 + vec[2]^2 + vec[3]^2)
    return {vec[1]/len, vec[2]/len, vec[3]/len}
end
 
function dot (vec1, vec2)
    d = vec1[1]*vec2[1] + vec1[2]*vec2[2] + vec1[3]*vec2[3]
    return d < 0 and -d or 0
end
 
function draw_sphere (radius, k, ambient)
    -- starting height for printing
    ln = 950
    for i = math.floor(-radius),-math.floor(-radius) do
        x = i + .5
        local line = ''
        for j = math.floor(-2*radius),-math.floor(-2*radius) do
            y = j / 2 + .5
            if x^2 + y^2 <= radius^2 then
                vec = normalize{x, y, math.sqrt(radius^2 - x^2 - y^2)}
                b = dot(light,vec) ^ k + ambient
                intensity = math.floor ((1 - b) * #shades)
                line = line .. (shades[intensity] or shades[1])
            else
                line = line .. ' '
            end
        end
        ln = ln - 14
        font("courier")
        fill(255, 255, 255, 255)
        fontSize(12)
        text(line,384,ln)
    end
end
 

Hi All,

Whilst struggling, as ever, in getting my head round spatial geometry (trying to draw a sphere in 3D) - I stumbled on something that amused me (http://rosettacode.org/wiki/Draw_a_sphere). Whilst digesting the reference I noted someone had kindly posted a Lua version of the code involved. This was virtually 100 percent transferable to Codea - just a little tickling from me. I hope you find the code of interest.