--

-- ////\\\\

-- ////\\\\ TUTORIAL

-- ////\\\\ PART 4

-- \\\\////

-- \\\\//// ANIMATION

-- \\\\////

--

local viewport = { width = 128, height = 64, frame = 0 }

local amplitude = 10

local rate = 10

-- Main

function init()

-- Render Style

screen.level(15)

screen.aa(0)

screen.line_width(1)

-- Center focus

reset()

-- Render

redraw()

end

function reset()

amplitude = 10

end

-- Interactions

function key(id,state)

reset()

redraw()

end

function enc(id,delta)

if id == 2 then

amplitude = clamp(amplitude + (delta/2),0,20)

else

rate = clamp(rate + (delta/10),2,20)

end

redraw()

end

-- Render

function draw_frame()

screen.rect(1, 1, viewport.width-1, viewport.height-1)

screen.stroke()

end

function draw_wave()

for i = 1,126 do

x = i

y = (math.sin((viewport.frame+i)/rate) * amplitude) + (viewport.height/2)

screen.pixel(x,y)

end

screen.fill()

end

function draw_label()

screen.move(5,viewport.height - (8 * 1))

screen.text(amplitude..':'..rate)

screen.stroke()

end

function redraw()

screen.clear()

draw_frame()

draw_wave()

draw_label()

screen.update()

end

-- Utils

function clamp(val,min,max)

return val < min and min or val > max and max or val

end

-- Interval

re = metro.init()

re.time = 1.0 / 15

re.event = function()

viewport.frame = viewport.frame + 1

redraw()

end

re:start()