View source for Scene Triggers

[[Category:Choreography]]
__TOC__

==Prerequisites==
* Basic {{faceposer|4}} knowledge ([[Choreography_Tool|Choreography tool]])
* Basic Hammer knowledge ([[Basic Construction|Simple brushwork]], [[Entity creation|entities]], [[Inputs_and_Outputs|entity I/O]])


==Introduction==

Scenes are able to fire map triggers for AI entities. To do this, a [[VCD]] (Valve Choreography Data) file will work in conjunction with outputs on a {{ent|logic_choreographed_scene}} entity to arrange inputs on AI entities. In this article, Fire Trigger events will be used in two examples. In Example #1, an AI entity will fire an input on itself. In Example #2, an AI entity will fire an input on a non-AI entity.

{{warning|For the purposes of this article, do not use quotes or periods in any of the fields to be filled.}}

==Overview for Example #1==

* Create a scene with a fire trigger event for a {{ent|npc_strider}} actor.
* Create a map with a simple room, a trigger brush, and configured entities.
* Compile and play the map.


==Scenario for Example #1==

A Strider will break itself to pieces. This level will involve an {{ent|info_player_start}} and a {{ent|npc_strider}}. A {{ent|trigger_once}} will be placed on the spawn zone, and will trigger two entities: {{ent|ai_relationship}} and {{ent|logic_choreographed_scene}}. The {{ent|ai_relationship}} will change the disposition of the strider to be neutral to the player, and the {{ent|logic_choreographed_scene}} will involve the {{ent|npc_strider}} to fire its <code>Break</code> input on itself.

==Creating the Strider Scene==

Make a new scene named “BreakStrider" with one actor, named Strider (<code>!Target#</code> names can also be used. See the [[Choreography Implementation]] article for more details). Create a channel under Strider named “FireTrigger", and create a "Fire Trigger" event. In the event’s properties, put “Breaker" in the name field, select “1" from the scene trigger field’s drop-down menu, and put “0" in the absolute start time field. Hit OK afterwards. This tells the game that the "Fire Trigger" event will occur immediately after the scene starts and will only be used by the Strider actor. Save the scene and rebuild [[scenes.image]].

[[File:St_scene.jpg|The scene with properties for a fire trigger event.]]

==Creating the Strider Map==

Make a new map named and create a 832 x 832 x 832 unit block, then hollow out the walls by -8 units. Next, place an <code>[[info_player_start]]</code> entity in an acceptable spot, preferably near one of the walls and centered. Set the angle to the opposite of the wall, to give the player a good view of the room. After that, place a {{ent|npc_strider}} in the map far enough from the {{ent|info_player_start}} so that the player will be able to see most of the strider from a distance. Make sure to put at least one {{ent|info_node}} in the map, preferably in its center.

[[File:St_view.jpg|The view of the npc_strider from the info_player_start.]]

{{note|The teal box is the {{ent|npc_strider}}.}}

Name the strider “Strider" (''The same name as the actor.'') Since Striders are naturally hostile to the player, the disposition of the Strider will need to be changed. Place an {{ent|ai_relationship}} entity in the map. Name it “Neutral", choose “Strider" as the subject, put “<code>!player</code>" as the target, set the disposition as “Neutral", and fill in “100" for the disposition priority. Close the property box.


Next, place a {{ent|logic_choreographed_scene}} entity in the map. Name it “BreakScene", and browse for the .vcd file previously created for the scene file field. Set target 1 as “Strider". Add the following output: 


:{| border=1 cellpadding="2" cellspacing="1"
|- align=left style="background:#DCDCDC; color:black"
!
! My Output > !! Target Entity !! Target Input !! Parameter !! Delay !! Only Once
|-
| [[File:Io11.png]] || OnTrigger1 || Strider || Break || &nbsp; || 0 || No
|}

{{note|This tells the game that when scene trigger “1" in the .vcd file is reached, the entity named “Strider" will use the Break input specified in <code>[[npc_strider]]</code>. OnTrigger# corresponds with the value in the Scene Trigger field; OnTrigger4 will only be started by a fire trigger event with a scene trigger value of 4, for example.}}


Finally, the {{ent|ai_relationship}} and {{ent|logic_choreographed_scene}} entities must be triggered themselves. A trigger brush will be placed on the {{ent|info_player_start}} so that the triggering will occur as the map starts. Create a brush on the {{ent|info_player_start}}, and tie it to a {{ent|trigger_once}} entity. Add the following outputs to the brush: 


:{| border=1 cellpadding="2" cellspacing="1"
|- align=left style="background:#DCDCDC; color:black"
!
! My Output > !! Target Entity !! Target Input !! Parameter !! Delay !! Only Once
|-
| [[File:Io11.png]] || OnTrigger || Neutral || ApplyRelationship || &nbsp; || 0 || No
|-
| [[File:Io11.png]] || OnTrigger || BreakScene || Start || &nbsp; || 1 || No
|}


[[File:St_tbrush.jpg|Outputs for the trigger brush]]


Compile the map. Run {{hl2|4}} afterwards, and load the map. The scene will play and produce the expected results. 

==Overview for Example #2==

* Create a scene with an NPC firing a trigger to open a door.
* Create a room with a {{ent|prop_door_rotating}}, a {{ent|npc_breen}}, and other required entities.
* Compile and play the map.


==Scenario for Example #2==

A NPC will walk to a door, temporarily wait, and open the door. This level will involve a {{ent|info_player_start}}, a {{ent|trigger_once}} brush, a {{ent|logic_choreographed_scene}}, a {{ent|npc_breen}}, a {{ent|prop_door_rotating}}, and an {{ent|info_target}}. As the player spawns, the {{ent|trigger_once}} brush will start the {{ent|logic_choreographed_scene}}. The scene will tell the {{ent|npc_breen}} to walk to the {{ent|info_target}}, wait for one second, and fire a scene trigger to open the {{ent|prop_door_rotating}}. 


==Creating the Door Scene==

Make a new scene called “OpenDoor". Name the actor <code>!target1</code> and create two channels. Name the first channel “moveto" and the second channel “firetrigger". Create a "Move To" event in the “moveto" channel, give the event a name, put “spot" in the “Move to Actor" field, choose “Walk" in the field below, set the start time to “0", set the end time to “2", and push OK. In the “firetrigger" channel, create a "Fire Trigger" event. Name the event “Open the door", select “8" in the “Scene Trigger" field, set the start time to “3", and push OK.

The scene is now created. This .vcd will dictate that as the scene begins, the actor assigned to <code>!target1</code> in the {{ent|logic_choreographed_scene}} will immediately spend two seconds moving to the entity named “spot". Afterwards, one second will pass, and the actor will fire the input specified in the <code>OnTrigger8</code> output of the {{ent|logic_choreographed_scene}}.


==Creating the Door Map==

Create a new map, make a 320 x 320 x 320 unit block, and hollow out the room by -8 units. Place an {{ent|info_player_start}}, a <code>[[trigger_once]]</code>, and a {{ent|logic_choreographed_scene}} in the map. Move these three entities to a position similar to the prior map with the Strider. Now, place a {{ent|prop_door_rotating}} entity in the middle of the map. Change the default settings for the fields specified with the following:


{| class="wikitable"
|-
! Keyvalue !! Value
|-
| Name || Door
|-
| World model || <code>models/props_c17/door01_left.mdl</code>
|-
| Skin || 2
|-
| Delay before close || -5
|}


Position the {{ent|prop_door_rotating}} so that that it doesn’t clip into any surfaces, and that the front or back of the door would face the {{ent|info_player_start}}. Rotate the {{ent|info_player_start}} accordingly. Now, create an {{ent|info_target}} and place it on the opposite side of the door that the player is facing at. Name it “spot" (the name of the target for the actor to move towards), and position it slightly above the floor. Lastly, create an {{ent|npc_breen}} entity, place it near the wall opposite of the {{ent|info_player_start}}, and rotate it so that it faces the {{ent|prop_door_rotating}}. The map should look somewhat like this:

[[File:St_view2.jpg|The layout of Example #2]]


Give the {{ent|npc_breen}} entity a name, and open up the properties for the {{ent|logic_choreographed_scene}}. Name it "LCS1", specify the path to OpenDoor, set “Target 1" to the {{ent|npc_breen}}, and add the following output:


:{| border=1 cellpadding="2" cellspacing="1"
|- align=left style="background:#DCDCDC; color:black"
!
! My Output > !! Target Entity !! Target Input !! Parameter !! Delay !! Only Once
|-
| [[File:Io11.png]] || OnTrigger8 || Door || Open || &nbsp; || 0 || No
|}


Finally, add an output to the {{ent|trigger_once}} as follows:


:{| border=1 cellpadding="2" cellspacing="1"
|- align=left style="background:#DCDCDC; color:black"
!
! My Output > !! Target Entity !! Target Input !! Parameter !! Delay !! Only Once
|-
| [[File:Io11.png]] || OnTrigger || LCS1 || Start || &nbsp; || 0 || No
|}


Compile and play the map. The scene will play as expected. This ends Example #2.

==Conclusion==

By using fire trigger events, scene designers can have more control over actors, such as the number of triggers to be fired per actor and when. Appropriate usage of "Fire Trigger" events can make one’s choreography more cohesive.

If one were to fire an input on a non-AI entity, a NPC is required for the scene. Defining the non-AI entity as an actor in a scene and adding the appropriate outputs will result in the engine not being able to find the actor. Passing the scene trigger through the AI entity makes said entity "bridge" the connection between a .vcd file and a non-AI entity.


==Example Archive==

An [http://www.geocities.com/sodabus_vdc/st_wiki.zip example archive] {{Dead link}} is included with this article.