Placeable Markers
In this section, we'll spawn items like NPCs, power ups etc in our dungeon.
For this, we'll do the following:
Use the
Spawn Itemnode in the flow graph. This will add items in the layout graphCreate
Placeable Markerassets in the content browser and drop a few of them in the snap modules so that the builder can spawn them at those places when necessaryUse the Theme engine to spawn the markers
Spawn Items in Flow Graph
Open up the flow graph and assign the module database in the editor settings like before
Create a new Spawn Items node and link it up as shown below:
Inspect the properties of the Spawn Items node. Add two paths in the Paths array and assign the ids of the main path (main) and the alternate path (alt)
We'd like to eventually spawn something in the modules using the theme file. We'll provide a marker name here, so we can create a corresponding marker node in the theme file and add our NPC blueprint there
Set the Marker Name parameter to Grunt
Leave the rest of the properties unchanged and hit Build
The nodes now in the green path (main) and orange path (alt) have red enemy items that were created using the Spawn Item node
Add a description to this node
Placeable Markers
A placeable marker is an asset you create in the content browser. You can then drag and drop these assets anywhere on the scene. You can then use the theme file to spawn objects at that location.
A placeable marker asset can contain more than one marker name. For example, a placeable marker asset named PM_Enemies may contain a list of marker names like (Grunt, FireTroll, IceTroll, Goblin). In your snap module, you'd place these markers in appropriate locations (say 10 different locations within the room).
If the dungeon builder needs to spawn a Grunt marker 4 times inside the room, it will first find all the existing and compatible marker assets placed in the room. In this case PM_Enemies would be compatible since it contains a Grunt marker. Since we have 10 of these in the room module, it will randomly pick 4 from them and use the theme file to spawn the grunt blueprint
Create Asset
Right click on the Content Browser and choose Dungeon Architect > Placeable Marker
Rename the asset to PM_Enemies
Double click the asset to open up the editor. Add a Grunt marker (since we specified this earlier in the Spawn Items node). Add a few more markers for future use like IceTroll, FireTroll, Goblin
Save the asset and close this editor
Add to Snap Modules
Open up the previously created room module
We've added a bit of geometry to the room. The snap system gives complete freedom to the artist to design the room as they see fit. In that same spirit, the artist should also have control on where the markers spawn. This is where placeable markers come in
Drag drop the placeable marker asset that you've created before, on to the scene
When you drag drop a marker asset in the scene, it will create a placeable marker actor. Select the actor that you just dropped
It will show some debug info, like the maker asset name, and the marker names it contains
Rotate the actor as needed. The red arrow shows the orientation of the marker. When the theme engine spawns an actor here, it will do so with this rotation
Add a few more markers. Add at least 4 markers, since we are adding a maximum of 4 enemy items per node in the flow graph using Spawn Item, but adding more is always better. We'll add a few on top of the bridge, on the ramp, and some more on the ground
Do this for all the modules you've created so far that would need this marker in it
Open up the Lift module and add a few more placeable markers there
Rebuild Module Database Cache
If you add / remove a placeable marker from a snap module, you'll need to rebuild the module database cache
Open up the Module database we've created in the previous section and click Build Module Cache button. Save and close the module database editor
Update Theme File
We'll use a theme file to actually spawn our enemy blueprint.
Open Theme Editor
Open up the existing theme file we created in the previous section.
Change Builder Type
Click somewhere on an empty space in the graph to show the theme properties in the Details tab.
Scroll down to the Advanced section and set the Builder Class to SnapGridFlowBuilder
This will update all the marker nodes for that builder.
Create Marker
In the previous section, we assign the marker name of Grunt in the Spawn Items node. In the theme file, we'll create a new marker node and name it Grunt
Right click on the graph and choose Add Marker Node
Select the marker node and change the Marker name to Grunt in the properties
Add Enemy actor
Add your NPC character blueprint here. For this tutorial, we'll add a cube and adjust the size and scale
Resize the theme editor a bit and drag drop the proto cube on to the theme editor
This will create a new mesh node. Add it to the Grunt marker node
Select the cube mesh node and set the scale to (1, 1, 2)
Add a Material Override entry
Assign a red material to it
Save and close the Theme Editor
Build Dungeon
Open the map where we previously configured our dungeon and build it.
You'll see that enemies start to spawn at the locations where you've placed the markers
You can use this system to spawn anything (treasure chests, weapon racks, power ups or any gameplay blueprint)