Lephisto/scripts/ai/include/basic.lua

-- [[
--  Basic tasks for a pilot, no need to reinvent the wheel with these.
--
--  The idea is to have it all here and only really work on the "control"
--  functions and such for each AI.
--]]

--[[
--  Should be run when the pilot is in attack mode, something like:
--  if task == "attack" then attack_think() end
--  in control().
--]]
function attack_think()
  local enemy = ai.getenemy()
  local target = ai.targetid()

  -- Get new target if it's closer.
  if enemy ~= target then
    local dist = ai.dist(ai.pos(target))
    local range = ai.getweaprange()

    -- Shouldn't switch targets if close.
    if dist > range * 1.3 then
      ai.poptask()
      ai.pushtask(0, "attack", enemy)
    end
  end
end

--[[
--  Attacks the current target, task pops when target is dead.
--]]
function attack_default()
  local target = ai.targetid()
  ai.hostile(target) -- Mark as hostile.

  -- Make sure pilot exists.
  if not ai.exists(target) then
    ai.poptask()
    return
  end

  ai.settarget(target)

  -- Get stats about enemy.
  local dist = ai.dist(ai.pos(target))   -- Get distance.
  local range = ai.getweaprange()

  -- We first bias towards range.
  if dist > range then 
    local dir = ai.face(target) -- Normal face the target.

    local secondary, special = ai.secondary("Launcher")

    -- Shoot missiles if in range.
    if secondary == "Launcher" and
        dist < ai.getweaprange(1) then
      -- More lenient with aiming.
      if special == "Smart" and dir < 30 then
        ai.shoot(2)

      -- Non-smart miss more.
      elseif dir < 10 then
        ai.shoot(2)
      end
    end

    if dir < 10 then
      ai.accel()
    end

  -- Close enough to melee.
  else
    local secondary, special = ai.secondary("Weapon")
    local dir = ai.aim(target) -- we aim instead of face.

    -- Fire non-smart secondary weapons.
    if(secondary == "Launcher" and special ~= "Smart") or
        secondary == "Beam Weapon" then
      if dir < 10 or special == "Turret" then -- Need good acuracy.
        ai.shoot(2)
      end
    end

    if dir < 10 or ai.hasturrets() then
      ai.shoot()
    end
  end
end

--[[
--  Set attack function to be default. If you want to override use:
--  attack = attack_<type>
--  Right after including this file.
--]]
attack = attack_default

--[[
--  Attempt to land on a planet.
--]]
function land()
  local target = ai.target()
  local dir = ai.face(target)
  local dist = ai.dist(target)
  local bdist = ai.minbrakedist()

  -- Need to get closer.
  if dir < 10 and dist > bdist then
    ai.accel()
  -- Need to start braking.
  elseif dist < bdist then
    ai.poptask()
    ai.pushtask(0, "landstop", target)
  end
end

function landstop()
  ai.brake()

  if ai.isstopped() then
    local target = ai.target()
    ai.stop() -- Will stop the pilot if below err vel.
    ai.settime(0, rnd.int(8000, 15000)) -- We wait during a while.
    ai.poptask()
    ai.pushtask(0, "landwait", target)
  end
end

function landwait()
  local target = ai.target()
  local dist = ai.dist(target)
  
  -- In case for some reason landed far away..
  if dist > 50 then
    ai.poptask()
    ai.pushtask(0, "land", target)

  elseif ai.timeup(0) then
    ai.poptask() -- Ready to do whatever we were doing before.
  end
end

--[[
--  Attempts to run from the target.
--]]
function runaway()
  local target = ai.targetid()

  if not ai.exists(target) then
    ai.poptask()
    return
  end

  local dir = ai.face(target, 1)
  ai.accel()

  --[[
  --  TODO: Afterburner handling.
  --  if ai.hasafterburner() then
  --    ai.afterburn(true)
  --  end
  --]]
  if ai.hasturrets() then
    dist = ai.dist(ai.pos(target))
    if dist < ai.getweaprange() then
      ai.settarget(target)
      ai.shoot()
    end
  end
end

--[[
-- Start heading away to try to hyperspace.
--
-- Will need the following in control() to work:
--
-- local task = ai.taskname()
-- if task == "hyperspace" then
--   ai.hyperspace() -- Try to hyperspace.
-- end
--]]
function hyperspace()
  local dir = ai.face(-1) -- Face away from (0,0).
  if(dir < 10) then
    ai.accel()
  end
end