Creating Instanced Items #
In this section, we’ll demonstrate how to create a custom unique instanced item type called “gear.” To create gear we’ll go over the following steps:
- Create the gear’s
ext
instanced item template (ExtInstancedSpec
) andext
item mold (ExtInstancedItem
) in protos. - Define the catalog of gear instanced items in JSON.
- Customize an
InstancedItemPlugin
in Kotlin that buildsext
data for gear.
Get started #
Run the following commands in the terminal from the platform
directory to build the engine and make 5-ext
if it doesn’t already exist:
make skip-tests protos engine
make ext
Define the protos #
In this section, we’ll define the two protobuf definitions that make up ext
data for instanced items:
ExtInstancedSpec
templates the item’s customext
dataExtInstancedItem
contains theext
data of instanced items built in theInstancedItemPlugin
.
Edit the inventory content ext file #
Define the ExtInstancedSpec
templates for the gear-type items’ custom ext
data.
- Open
5-ext/ext-protos/src/main/proto/shared/inventoryContentExt.proto
. - In the
ExtInstancedSpec
message, add the following code to define theGearSpec
:
message ExtInstancedSpec {
oneof data {
GearSpec gear_spec = 1;
}
}
- Define custom
GearSpec
components by inserting the following message below theExtInstancedSpec
message. This message lists the values required when creating anext
data for a gear-type item.
message GearSpec {
int32 level_to_equip = 1;
string primary_attribute_spec_id = 2;
int32 primary_attribute_value_min = 3;
int32 primary_attribute_value_max = 4;
}
Edit the inventory ext file #
Define the ExtInstancedItem
mold that contains the ext
data for gear-type items.
- Open
5-ext/ext-protos/src/main/proto/shared/inventoryExt.proto
. - Edit the
ExtInstancedItem
message by inserting the following code:
message ExtInstancedItem {
oneof data {
Gear gear = 1;
}
}
- Define
Gear
by inserting the following message below theExtInstancedItem
message:
message Gear {
int32 attribute_value = 1;
repeated string socketed_runestones = 2;
}
Apply proto changes #
Run the following make command using platform
as the working directory to apply protobuf changes:
make ext-protos
Define the JSON catalog #
Instanced items are defined in a JSON item catalog with shared identifiers and configurations for all game content managed by the platform. This is where designers create player inventory specifications and include ext
data with their items.
If you do not already have the content source files initialized, runmake init-inventory-content
using a terminal from theplatform
directory.
Edit the instanced specs catalog #
Define gear-type items metal_sword_1
, metal_chest_2
, and metal_hat_3
in the instanced specs JSON catalog.
- Open
5-ext/content/src/InstancedSpecs.json
. - Insert the following code into the JSON catalog:
[
{
"catalogId": "metal_sword_1",
"name": "Copper Sword",
"tags": [
"weapon",
"1h"
],
"ext": {
"gearSpec": {
"levelToEquip": 1,
"primaryAttributeSpecId": "damage_physical",
"primaryAttributeValueMin": 5,
"primaryAttributeValueMax": 10
}
}
},
{
"catalogId": "metal_chest_2",
"name": "Bronze Breastplate",
"tags": [
"armor",
"chest",
"heavy-armor"
],
"ext": {
"gearSpec": {
"levelToEquip": 2,
"primaryAttributeSpecId": "resistance_physical",
"primaryAttributeValueMin": 35,
"primaryAttributeValueMax": 40
}
}
},
{
"catalogId": "metal_hat_3",
"name": "Iron Helmet",
"tags": [
"armor",
"head",
"heavy-armor"
],
"ext": {
"gearSpec": {
"levelToEquip": 3,
"primaryAttributeSpecId": "resistance_physical",
"primaryAttributeValueMin": 20,
"primaryAttributeValueMax": 25
}
}
}
]
Apply content data #
In order to register the content you just defined with Pragma Engine, you must apply your content data changes. You may apply content data either using the command line with make
or via an IntelliJ run configuration.