View source for Antlions: Random Spawn

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The great thing about these antlions is that they are made to be used with other little tools to make them spawn randomly when the player walks on a specified material, be it sand or any other material.

This tutorial will walk you through the making of a simple example of randomly unburrowing antlions.

== Getting started ==

First, make a map with sand and rocks. The situation we are attempting to create is that if the player walks on the sand, antlions come out near the player and attack, and the player is forced to walk on the rocks.

These are the entities we are going to need:

* [[npc_antlion]]
* [[env_shake]]
* [[ambient_generic]]
* [[npc_antlion_template_maker]]
* [[logic_relay]]
* [[env_player_surface_trigger]]
* [[info_node_hint]]

== Configuring the entities ==

First create an npc_antlion with the following properties.

{{entity-kvalue-start|[[npc_antlion]]}}
{{entity-kvalue|Name|AntLion|}}
{{entity-kvalue|Start Burrowed|Yes|}}
{{entity-kvalue-end}}

{{entity-flag-start}}
{{entity-flag|Template NPC|on|}}
{{entity-flag-end}}

Next, configure the entity that triggers inputs when the player walks on the sand:

{{entity-kvalue-start|[[env_player_surface_trigger]]}}
{{entity-kvalue|Name|SurfaceTrigger|}}
{{entity-kvalue|GameMaterialToWatch|sand|}}
{{entity-kvalue-end}}

{{entity-output-start|}}
{{entity-output||OnSurfaceChangedFromTarget|relay_expanse_disablespawn|Trigger||||When the player starts walking on the surface we have chosen, this entity triggers the relay OnSurfaceChangedToTarget.}}
{{entity-output||OnSurfaceChangedToTarget|relay_expanse_spawn|Trigger||||When the player steps off it, it triggers the relay OnSurfaceChangedFromTarget}}
{{entity-output-end}}

Then you will have to create the entity that creates the noise when the antlions are emerging.

{{entity-kvalue-start|[[ambient_generic]]}}
{{entity-kvalue|Name|sound_antlion_spawn|}}
{{entity-kvalue|SoundName|Streetwar.d3_c17_10b_rumble1|}}
{{entity-kvalue|Volume|8|}}
{{entity-kvalue|Fade In Time|1.5|}}
{{entity-kvalue|Fade Out Time|2|}}
{{entity-kvalue|Pitch|120|}}
{{entity-kvalue|Start Pitch|90|}}
{{entity-kvalue|Max Audible Distance|1250|}}
{{entity-kvalue-end}}

And the one to create the quake.

{{entity-kvalue-start|[[env_shake]]}}
{{entity-kvalue|Name|shake_antlion_spawn|}}
{{entity-kvalue|Amplitude|2|}}
{{entity-kvalue|Effect Radius|500|}}
{{entity-kvalue|Duration|3|}}
{{entity-kvalue|Frequency|100|}}
{{entity-kvalue-end}}

The following entity actually creates the antlions.

{{entity-kvalue-start|[[npc_antlion_template_maker]]}} 
{{entity-kvalue|Name|antlion_expanse_spawner|}} 
{{entity-kvalue|StartDisabled|Yes |We do not want the template_maker to start spawning at the beginning of the map.}} 
{{entity-kvalue|Num. of NPCs||Leave empty because we will check ''Infinite Children'' in flags.}} 
{{entity-kvalue|Frequency|0.35|}} 
{{entity-kvalue|Max Live NCPs||How many antlions can live at same time, 8 for example.}} 
{{entity-kvalue|Name Of Template NPC|AntLion|}} 
{{entity-kvalue|Spawn On HintGroup|antlion_expanse_spawn_nodes|}} 
{{entity-kvalue|Spawn Radius|1000|}} 
{{entity-kvalue|Spawn Target|!player|The target that the antlions will attack.}} 
{{entity-kvalue|Ignore Bugbait|No|}} 
{{entity-kvalue-end}} 

{{entity-flag-start|}}
{{entity-flag|Infinite Children|on|}}
{{entity-flag-end}}

{{entity-output-start|}}
{{entity-output||OnAllSpawnedDead|antlion_expanse_spawner|SetMaxChildren|8|9.00||..that means if all antlions are dead it resets the max number to 8 to prevent any problems}}
{{entity-output-end}}

Add the first logic_relay:

{{entity-kvalue-start|[[logic_relay]]}}
{{entity-kvalue|Name|relay_expanse_spawn|}}
{{entity-kvalue-end}}

{{entity-output-start|}}
{{entity-output||OnTrigger|sound_antlion_spawn|PlaySound||||When this relay is triggered it plays the sound.}}
{{entity-output||OnTrigger|relay_expanse_disablespawn|CancelPending||||}}
{{entity-output||OnTrigger|shake_antlion_spawn|StartShake||0.10||The ground shakes.}}
{{entity-output||OnTrigger|antlion_expanse_spawner|Enable||1.00||And the npc_antlion_template_maker enables 1 second after we walked on the ground, which makes an effect like the antlions are coming up.}}
{{entity-output-end}}

Add another logic_relay...

{{entity-kvalue-start|[[logic_relay]]}}
{{entity-kvalue|Name|relay_expanse_disablespawn|}}
{{entity-kvalue-end}}
with the following outputs:
{{entity-output-start|}}
{{entity-output||OnTrigger|sound_antlion_spawn|StopSound||||When this relay is triggered, the sound stops.}}
{{entity-output||OnTrigger|shake_antlion_spawn|StopShake||||Also, the shake stops..}}
{{entity-output||OnTrigger|antlion_expanse_spawner|Disable||0.50||..and the template_maker disables}}
{{entity-output||OnTrigger|relay_expanse_spawn|CancelPending||0.50||}}
{{entity-output-end}}

Another group of entities are to set where the antlions can spawn, you must put one everywhere that the antlion can possibly spawn, and the [[npc_antlion_template_maker]] will pick the one nearest the player.

{{entity-kvalue-start|[[info_node_hint]]}}
{{entity-kvalue|Hint|AntLion Burrow Point|}}
{{entity-kvalue|Hint Group|antlion_expanse_spawn_nodes|}}
{{entity-kvalue-end}}

== Notes ==

The antlions use [[info_node]] to navigate on the ground, and "fly" by using loose jump parameters.

To make them follow a precise path, use [[path_corner]]s and set it to the antlion's path corner, and place [[info_node]]s around the way so the antlions can navigate through them.

If there is a wall in their way, make sure there is a jump connection, and the antlions will use it to fly above the wall.

=== Quick tutorial to making antlions follow a path ===

If you want the antlions to run to a precise target, use [[aiscripted_schedule]], name it and configure:

{{entity-kvalue-start|[[aiscripted_schedule]]}}
{{entity-kvalue|Target Npc|Antlion |}}
{{entity-kvalue|Search Radius||..if there are more than one target, put 0.}}
{{entity-kvalue|All In Radius||..if there are more than one target, put yes.}}
{{entity-kvalue|Ai State To Set||..choose one}}
{{entity-kvalue|Schedule to run||..choose one}}
{{entity-kvalue|Interruptability||..choose one}}
{{entity-kvalue|Goal Entity||..is the target, it can be one precise or a classname, like [[npc_citizen]]}}
{{entity-kvalue-end}}

Then at the [[npc_antlion_template_maker]], add the following output:

{{entity-output-start|}}
{{entity-output||OnSpawnNpc|AiSchedule|StartSchedule||||}}
{{entity-output-end}}

[[Category: Level Design]]
[[Category: Tutorials]]
[[Category:Abstract Mapping]]