gistfile1.lua

args = table.concat({...}, " ")
print("f(x,y) = " .. args)
f = loadstring('return ' .. args)
env = {}
setmetatable(env, {["__index"] = math})
setfenv(f, env)

p = peripheral.wrap("right") --hardcoded :P

p.clearMap()
p.appendLayer()
p.appendLayer()
p.setMapInfo({
  ['layers'] = {
    [0] = 128,
    [1] = 255
   }
})

x_min = -1
x_max = 1

y_min = -1
y_max = 1

h_min = -1
h_max = 1

scale = 64.0 / (h_max - h_min)

h_zero = (0 - h_min) * scale

render_zero = h_max > 0 and h_min < 0

step_x = (x_max - x_min) / 64.0
step_y = (y_max - y_min) / 64.0
  
x = x_min
for row = 0,63 do
  y = y_min
  for column = 0,63 do
    if render_zero then
      p.setPoint(row, column, 0, h_zero, 1)
    end
    
    env.x = x
    env.y = y
    value, color = f()
    
    if value >= h_min and value <= h_max then
      h = (value - h_min) * scale
      p.setPoint(row, column, 1, h, color or 4)
    end
           
    y = y + step_y
  end
  
  x = x + step_x
end