graphics

--Focal distance. Tweak to change lens angle
local focalDistance = 20
--Display width and height.
local dispWidth, dispHeight = term.getSize()

function project(vertex)
    local zval = vertex.z
    if zval == 0 then zval = 1 end --Stops divide by zeros

    --I've applied centring to the display (after all the camera doesn't need to include this)
    --Note focal projection is square but centring is applied according to screen dimensions
    local xmap = (focalDistance * vertex.x) / (vertex.z + math.min(dispHeight,dispWidth)/2) + dispWidth/3
    local ymap = (focalDistance * vertex.y) / (vertex.z + math.min(dispHeight,dispWidth)/2) + dispHeight/2

    --Correcting for pixel size
    xmap = (3 * xmap) / 2

    return { x = xmap, y = ymap }
end