====== Part 17 - Timeline Tracks ======

We could set up a spawner to create a load of monsters for us, but we'll use a timeline instead. A timeline can issue commands.

Our timeline will simply issue the same create object command over and over in a loop.

Before we do this, remove the single monster from the Scene. We don't need it any more:

<code=ini>
[Scene]
ChildList = PlatformObject # MiddlePlatformObject #
TopLeftPlatformObject # TopPlatformObject #
TopRightPlatformObject #
StarObject
</code>

Now to create a simple track:

<code=ini>
[MonsterMakerTrack]
1    = Object.Create MonsterObject
Loop = True
</code>

This will create monsters over and over every second for us. But the monster objects need to start at a random position each time. Change the monster object to have a range of starting x positions:

<code=ini>
[MonsterObject]
Graphic      = MonsterGraphic
AnimationSet = MonsterAnimationSet
Position     = (-380, -300, 0) ~ (200, -200, 0)
Scale        = 2.0
Body         = MonsterBody
</code>

Finally, to actually use the track which will create monsters, add it to the TrackList property in the Scene section:

<code=ini>
[Scene]
ChildList = PlatformObject # MiddlePlatformObject #
TopLeftPlatformObject # TopPlatformObject #
TopRightPlatformObject #
StarObject
TrackList = MonsterMakerTrack
</code>

Looking great! Monsters should be dropping in all over the place:

{{:guides:beginners:beginners-42-timeline-monsters.png?nolink|}}

Some tweaks can be added to the monster and the body to improve things a little:

<code=ini>
[MonsterObject]
Graphic      = MonsterGraphic
AnimationSet = MonsterAnimationSet
Position     = (-380, -300, 0) ~ (200, -200, 0)
Speed        = (-20, 0, 0) ~ (20, 0, 0)
Scale        = 2.0
Body         = MonsterBody
 
[MonsterBody]
Dynamic            = true
PartList           = MonsterBodyPart
AngularDamping     = 50
LinearDamping      = 0.2
 
[MonsterBodyPart]
Type        = box
Solid       = true
SelfFlags   = monster
CheckMask   = hero # platforms # bullet
Friction    = 0
Restitution = 0.2
Density     = 20
</code>

The ''Speed'' on the object will give the monsters a little random left/right movement. The ''Friction'' on the bodypart will make the monster less slippery on the ground. 

The ''LinearDamping'' on the body will slow him down a little over time if he's too fast. The high ''AngularDamping'' will ensure the monster tips over the edge but not rotate and tumble wildly.

Finally, a touch of ''Restitution'' on the body will allow it to bounce just a touch when landing from a height.

That should work a little better.

----

Next: [[en:guides:beginners:exploding_monsters|Part 18 – Exploding Monsters]].

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