Plasma Tier 3 GPU Buffering Demo For OpenComputers (Version 0.1)

local component = require("component")
local gpu = component.gpu
local computer = require("computer")
local event = require("event")

-- Screen dimensions
local w, h = gpu.getResolution()

-- Optimization: Precalculate constants
local pi2 = math.pi * 2
local hw, hh = w / 2, h / 2

-- Plasma parameters
local time = 0
local speed = 0.05

-- Color palette (optimized for performance)
local colors = {
  0x000000, 0x0000FF, 0x00FFFF, 0x00FF00,
  0xFFFF00, 0xFF0000, 0xFF00FF, 0xFFFFFF
}

-- Initialize buffers
local frontBuffer = {}
local backBuffer = {}
for y = 1, h do
  frontBuffer[y] = {}
  backBuffer[y] = {}
  for x = 1, w do
    frontBuffer[y][x] = 0
    backBuffer[y][x] = 0
  end
end

-- Precalculate sine lookup table
local sinLookup = {}
for i = 0, 255 do
  sinLookup[i] = math.sin(i * pi2 / 256)
end

-- Fast sine approximation
local function fastSin(x)
  return sinLookup[math.floor(x * 40.743) % 256]
end

-- Efficient drawing function
local function drawChanges(changes)
  local lastColor = nil
  for i = 1, #changes do
    local change = changes[i]
    if change[3] ~= lastColor then
      gpu.setBackground(change[3])
      lastColor = change[3]
    end
    gpu.set(change[1], change[2], " ")
  end
end

-- Swap buffers and update screen (minimized GPU calls)
local function swapBuffers()
  local changes = {}
  for y = 1, h do
    for x = 1, w do
      if backBuffer[y][x] ~= frontBuffer[y][x] then
        table.insert(changes, {x, y, colors[backBuffer[y][x]]})
        frontBuffer[y][x] = backBuffer[y][x]
      end
    end
  end

  -- Batch update GPU
  drawChanges(changes)
end

-- FPS counter variables
local fpsCount = 0
local fpsTimer = 0
local currentFPS = 0

-- Function to update FPS
local function updateFPS()
  fpsCount = fpsCount + 1
  local currentTime = computer.uptime()
  if currentTime - fpsTimer >= 1 then
    currentFPS = fpsCount
    fpsCount = 0
    fpsTimer = currentTime
  end
end

-- Function to display FPS
local function displayFPS()
  gpu.setBackground(0x000000)
  gpu.setForeground(0xFFFFFF)
  gpu.set(1, 1, string.format("FPS: %d", currentFPS))
end

-- Main plasma update function
local function updatePlasma()
  for y = 1, h do
    for x = 1, w do
      -- Optimized plasma calculation using fast sine
      local v = fastSin(x / 16 + time)
        + fastSin(y / 8 + time)
        + fastSin((x + y) / 16 + time)
        + fastSin(math.sqrt((x-hw)^2 + (y-hh)^2) / 8)

      -- Map value to color index
      local index = math.floor((v + 4) * (#colors / 8)) % #colors + 1

      -- Update back buffer
      backBuffer[y][x] = index
    end
  end

  -- Swap buffers and update screen
  swapBuffers()

  -- Update time (with wrapping to prevent overflow)
  time = (time + speed) % pi2
end

-- Main loop
local running = true
event.timer(0, function()
  while running do
    local startTime = computer.uptime()

    updatePlasma()
    updateFPS()
    displayFPS()

    local endTime = computer.uptime()
    local frameTime = endTime - startTime
    local sleepTime = math.max(0, 1/60 - frameTime)  -- Aim for 60 FPS
    os.sleep(sleepTime)
  end
end, math.huge)

-- Event handler to stop the program
event.listen("key_down", function(_, _, _, code)
  if code == 16 then  -- 'Q' key
    running = false
    event.push("interrupt")
  end
end)

-- Wait for interrupt
event.pull("interrupt")
gpu.setBackground(0x000000)
gpu.setForeground(0xFFFFFF)
gpu.fill(1, 1, w, h, " ")
print("Plasma effect stopped.")