Water Simulation/Source

--Water Simulation with waves based on the tutorial on gamedeveloppement.tutplus.com by Michael Hoffman waterColor = {0, 0.5, 1, 1} -- <<-- Transparency to 0.5

function main()

  -- Set draw screen
  draw.setscreen(1)
  draw.settitle('Water Simulation')
  draw.clear()

  -- Initialize variables
  initializeVariables()

  -- Do events
  draw.tracktouches(clicked, moved, ended)
  while true do
     draw.doevents()
     update()
     drawScreen()
     sleep(10)
  end

end

function initializeVariables()

  sw, sh = draw.getport()
  ballRadius, ballDropped = 20, false
  tension, dampening, spread = 0.025, 0.04, 0.25
  waterLevel, count = sh/2, sw/10 + 1
  height, velocity = {}, {}

  for i = 1, count do
     height[i], velocity[i] = waterLevel, 0
     height[i] = waterLevel
  end

end

function update()

  -- Update springs
  for i = 1, count do
     local x = height[i] - waterLevel
     local acceleration = -tension * x - velocity[i]*dampening
     height[i] = height[i] + velocity[i]
     velocity[i] = velocity[i] + acceleration
  end

  -- Make the waves propagate
  leftDeltas, rightDeltas = {}, {}
  for j = 1, 8 do
     for i = 1, count do
        if i > 1 then
           leftDeltas[i] = spread * (height[i] - height[i-1])
           velocity[i-1] = velocity[i-1] + leftDeltas[i]
        end
        if i < count-1 then
           rightDeltas[i] = spread * (height[i] - height[i+1])
           velocity[i+1] = velocity[i+1] + rightDeltas[i]
        end
     end
     for i = 1, count do
        if i > 1 then height[i-1] = height[i-1] + leftDeltas[i] end
        if i < count-1 then height[i+1] = height[i+1] + rightDeltas[i] end
     end
  end

  if ballDropped == true then
     -- Accelerate the water spring
     spring = math.floor(ballX/10)
     if ballY > height[spring] then velocity[spring] = velocity[spring] + ballVelocity end

     -- Accelerate the ball
     if ballY < height[spring]+ballRadius then
        ballVelocity = ballVelocity + 6
     else
        ballVelocity = 5
     end
     ballY = ballY + ballVelocity

     -- Enable possibility to drop another ball
     if ballY > sh+ballRadius then ballDropped, ballX = false, 0 end
  end

end

function drawScreen()

  draw.beginframe() draw.clear()

  -- Draw the ball if necessary
  if ballX ~= nil then
     draw.setantialias(true)
     draw.setlinestyle(4, 'round')
     draw.circle(ballX, ballY, ballRadius, draw.black)
  end

  -- Draw the water
  draw.setantialias(false) -- Smoother water
  for i = 1, count-1 do
     draw.filltriangle((i-1)*10, height[i], i*10, height[i+1], (i-1)*10, sh, waterColor)
     draw.filltriangle(i*10, height[i+1], i*10, sh, (i-1)*10, sh, waterColor)
  end

  draw.endframe()

end

function clicked(x, y) moved(x, y) end function moved(x, y)

  -- Move the ball according to the touch position
  if ballDropped == false and y < waterLevel and x > ballRadius and x < sw-ballRadius then ballX, ballY = x, y end

end function ended(x, y)

  -- Drop the ball
  ballDropped, ballVelocity = true, 0

end

main() -- --