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tutorial:entity [2023/09/13 20:30] (current) – ↷ Links adapted because of a move operation nebelnidas
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 +===== Creating an Entity =====
 +
 +//The source code for this project can be found [[https://github.com/Draylar/entity-testing/tree/entity|here]].//
 +
 +Entities are a movable object in a world with logic attached to them. A few examples include:
 +  * Minecarts
 +  * Arrows
 +  * Boats
 + 
 +Living Entities are Entities that have health and can deal damage. 
 +There are various classes that branch off `LivingEntity` for different purposes, including:
 +  * ''HostileEntity'' for Zombies, Creepers and Skeletons
 +  * ''AnimalEntity'' for Sheep, Cows and Pigs
 +  * ''WaterCreatureEntity'' for things that swim
 +  * ''FishEntity'' for fishies (use instead of ''WaterCreatureEntity'' for schooling behavior)
 + 
 +What you extend depends on what your needs and goals are. 
 +As you get further down the chain, the entity logic becomes more specific and curated to certain tasks.
 +The two generic entity classes that come after ''LivingEntity'' are:
 +  * ''MobEntity''
 +  * ''PathAwareEntity''
 + 
 +''MobEntity'' has AI logic and movement controls. ''PathAwareEntity'' provides extra capabilities
 +for pathfinding favor, and various AI tasks require this to operate.
 +
 +In this tutorial, we will look at creating a cube entity that extends ''PathAwareEntity''.
 +This entity will have a model & texture. Movement and mechanics will be covered in a future tutorial.
 +
 +===== Creating & Registering an Entity =====
 +
 +Create a class that extends ''PathAwareEntity''. This class serves as the brains and main hub for our custom entity.
 +
 +<code java [enable_line_numbers="true"]>
 +/*
 + * Our Cube Entity extends PathAwareEntity, which extends MobEntity, which extends LivingEntity.
 + *
 + * LivingEntity has health and can deal damage.
 + * MobEntity has movement controls and AI capabilities.
 + * PathAwareEntity has pathfinding favor and slightly tweaked leash behavior.
 + */
 +public class CubeEntity extends PathAwareEntity {
 +
 +    public CubeEntity(EntityType<? extends PathAwareEntity> entityType, World world) {
 +        super(entityType, world);
 +    }
 +}
 +</code>
 +
 +You can register this entity under the ''ENTITY_TYPE'' registry category.
 +Fabric provides a ''FabricEntityTypeBuilder'' class, which is an extension of the vanilla ''EntityType.Builder'' class.
 +The Fabric builder class provides extra methods for configuring your entities' tracking values.
 +
 +<code java [enable_line_numbers="true"]>
 +public class EntityTesting implements ModInitializer {
 +
 +    /*
 +     * Registers our Cube Entity under the ID "entitytesting:cube".
 +     *
 +     * The entity is registered under the SpawnGroup#CREATURE category, which is what most animals and passive/neutral mobs use.
 +     * It has a hitbox size of .75x.75, or 12 "pixels" wide (3/4ths of a block).
 +     */
 +    public static final EntityType<CubeEntity> CUBE = Registry.register(
 +            Registries.ENTITY_TYPE,
 +            new Identifier("entitytesting", "cube"),
 +            FabricEntityTypeBuilder.create(SpawnGroup.CREATURE, CubeEntity::new).dimensions(EntityDimensions.fixed(0.75f, 0.75f)).build()
 +    );
 +
 +    @Override
 +    public void onInitialize() {
 +        
 +    }
 +}
 +</code>
 +
 +Entities need //Attributes//, and a //Renderer// to function. 
 +
 +===== Registering Entity Attributes =====
 +
 +**Attributes** define the properties of the mob: how much health does it have? How much damage does it do? Does it have any default armor points?
 +
 +Most vanilla entities have a static method that returns their attributes (such as ''ZombieEntity#createZombieAttributes'').
 +Our custom entity doesn't have any unique properties, for now, so we can use ''MobEntity#createMobAttributes''.
 +
 +Vanilla has a ''DefaultAttributeRegistry'' class for registering these properties. 
 +It isn't publicly exposed or easily available, so Fabric provides a ''FabricDefaultAttributeRegistry'' class.
 +The registration of default attributes should occur somewhere in your mod's initialization phase:
 +
 +<code java [enable_line_numbers="true"]>
 +public class EntityTesting implements ModInitializer {
 +    
 +    public static final EntityType<CubeEntity> CUBE = [...];
 +
 +    @Override
 +    public void onInitialize() {
 +        /*
 +         * Register our Cube Entity's default attributes.
 +         * Attributes are properties or stats of the mobs, including things like attack damage and health.
 +         * The game will crash if the entity doesn't have the proper attributes registered in time.
 +         *
 +         * In 1.15, this was done by a method override inside the entity class.
 +         * Most vanilla entities have a static method (eg. ZombieEntity#createZombieAttributes) for initializing their attributes.
 +         */
 +        FabricDefaultAttributeRegistry.register(CUBE, CubeEntity.createMobAttributes());
 +    }
 +}
 +</code>
 +
 +===== Registering Entity Renderer =====
 +
 +The last requirement of an entity is a **Renderer**. Renderers define *what* the entity looks like, generally by providing a model.
 +''MobEntityRenderer'' is the best choice for MobEntities. The class has one required method override for providing a texture,
 +and wants 3 parameters for the super constructor:
 +  * ''EntityRenderDispatcher'' instance
 +  * ''Model'' of our entity
 +  * shadow size of our entity as a ''float''
 + 
 +The following code showcases a simple entity renderer with a shadow size of 0.5f
 +and texture at ''resources/assets/entitytesting/textures/entity/cube/cube.png''.
 +Note that the texture and model class will be created in the next step.
 +
 +<code java [enable_line_numbers="true"]>
 +/*
 + * A renderer is used to provide an entity model, shadow size, and texture.
 + */
 +public class CubeEntityRenderer extends MobEntityRenderer<CubeEntity, CubeEntityModel> {
 +
 +    public CubeEntityRenderer(EntityRendererFactory.Context context) {
 +        super(context, new CubeEntityModel(context.getPart(EntityTestingClient.MODEL_CUBE_LAYER)), 0.5f);
 +    }
 +
 +    @Override
 +    public Identifier getTexture(CubeEntity entity) {
 +        return new Identifier("entitytesting", "textures/entity/cube/cube.png");
 +    }
 +}
 +</code>
 +
 +To register this renderer, use ''EntityRendererRegistry'' in a **client initializer**:
 +<code java [enable_line_numbers="true"]>
 +@Environment(EnvType.CLIENT)
 +public class EntityTestingClient implements ClientModInitializer {
 +    public static final EntityModelLayer MODEL_CUBE_LAYER = new EntityModelLayer(new Identifier("entitytesting", "cube"), "main");
 +    @Override
 +    public void onInitializeClient() {
 +        /*
 +         * Registers our Cube Entity's renderer, which provides a model and texture for the entity.
 +         *
 +         * Entity Renderers can also manipulate the model before it renders based on entity context (EndermanEntityRenderer#render).
 +         */
 +        EntityRendererRegistry.INSTANCE.register(EntityTesting.CUBE, (context) -> {
 +            return new CubeEntityRenderer(context);
 +        });
 +        // In 1.17, use EntityRendererRegistry.register (seen below) instead of EntityRendererRegistry.INSTANCE.register (seen above)
 +        EntityRendererRegistry.register(EntityTesting.CUBE, (context) -> {
 +            return new CubeEntityRenderer(context);
 +        });
 +        
 +        EntityModelLayerRegistry.registerModelLayer(MODEL_CUBE_LAYER, CubeEntityModel::getTexturedModelData);
 +    }
 +}
 +</code>
 +
 +===== Creating a Model and Texture =====
 +
 +The final step to finishing our entity is creating a model and texture. 
 +Models define the //structure// of the entity, while the texture provides the color.
 +
 +Standard models define "parts", or ''ModelPart'' instances at the top of the class, 
 +initialize them in the constructor, obtain data in the ''getTexturedModelData'' method, and render them in the ''render'' method. 
 +Note that ''setAngles'' and ''render'' are both required overrides of the ''EntityModel'' class.
 +
 +<code java [enable_line_numbers="true"]>
 +public class CubeEntityModel extends EntityModel<CubeEntity> {
 +
 +    private final ModelPart base;
 +
 +    public CubeEntityModel(ModelPart modelPart) {
 +        this.base = modelPart.getChild(EntityModelPartNames.CUBE);
 +    }
 +    
 +    [...]
 +}
 +</code>
 +
 +After creating a part, we need to add a shape to it.
 +To do so, we must add a child to the root. The texture location for the new part is located in ''.uv'',
 +the offset for it is located in the first 3 numbers of ''.cuboid'', and the size is the last 3 numbers in ''.cuboid''
 +Note that the origin of a model starts at the corner, so you will need to offset the part to center it:
 +
 +<code java [enable_line_numbers="true"]>
 +public class CubeEntityModel extends EntityModel<CubeEntity> {
 +
 +    private final ModelPart base;
 +
 +    public CubeEntityModel() {
 +        [...]
 +    }
 +    
 +    // You can use BlockBench, make your model and export it to get this method for your entity model.
 +    public static TexturedModelData getTexturedModelData() {
 +        ModelData modelData = new ModelData();
 +    ModelPartData modelPartData = modelData.getRoot();
 +        modelPartData.addChild(EntityModelPartNames.CUBE, ModelPartBuilder.create().uv(0, 0).cuboid(-6F, 12F, -6F, 12F, 12F, 12F), ModelTransform.pivot(0F, 0F, 0F));
 +    }
 +</code>
 +
 +Our entity model now has a single cube that is 12x12x12 wide (75% of a block) centered around 0, 0, 0.
 +''setAngles'' is used for animating the model, but we will keep it empty for now. 
 +''render'' is where we tell our cube to show up. Note that standard vanilla models appear //higher//
 +than the entity hitbox, so we translate the model down to account for this. 
 +
 +<code java [enable_line_numbers="true"]>
 +public class CubeEntityModel extends EntityModel<CubeEntity> {
 +    
 +    private final ModelPart base;
 +    
 +    public CubeEntityModel() [...]
 +    
 +    public static TexturedModelData getTexturedModelData() [...]
 +
 +    @Override
 +    public void setAngles(CubeEntity entity, float limbAngle, float limbDistance, float animationProgress, float headYaw, float headPitch) {
 +    }
 +
 +    @Override
 +    public void render(MatrixStack matrices, VertexConsumer vertices, int light, int overlay, float red, float green, float blue, float alpha) {
 +        ImmutableList.of(this.base).forEach((modelRenderer) -> {
 +            modelRenderer.render(matrices, vertices, light, overlay, red, green, blue, alpha);
 +        });
 +    }
 +}
 +</code>
 +
 +To complete our model, we need to add a texture file. The default texture size is 64 wide and 32 tall;
 +you can change this by adding a return of your texturedModelData
 +We will set it to 64x64 for our texture:
 +
 +{{https://i.imgur.com/JdF9zjf.png}}
 + 
 +<code java [enable_line_numbers="true"]>
 +public class CubeEntityModel extends EntityModel<CubeEntity> {
 +
 +    private final ModelPart base;
 +
 +    [...]
 +    
 +    public static TexturedModelData getTexturedModelData() {
 +        [...]
 +        return TexturedModelData.of(modelData, 64, 64);
 +    }
 +
 +    [...]
 +
 +</code>
 +
 +===== Spawning your Entity =====
 +
 +Be sure to add your client entrypoint to fabric.mod.json.
 +You can do this like so:
 +<code json>
 +
 +  "entrypoints": {
 +    "main": [
 +      "mod.fabricmc.entitytesting.EntityTesting"
 +    ],
 +    "client": [
 +      "mod.fabricmc.entitytesting.EntityTestingClient"
 +    ]
 +  },
 +</code>
 +You can spawn your entity by typing ''/summon entitytesting:cube'' in-game. Press f3+b to view hitboxes:
 +{{https://i.imgur.com/MmQvluB.png}}
 +
 +**NOTE:** If your entity does not extend ''LivingEntity'' you have to create your own spawn packet handler. Either do this through the networking API, or mixin to ''ClientPlayNetworkHandler#onEntitySpawn''
 +===== Adding tasks & activities =====
 +
 +To add activities see [[tutorial:villager_activities|here]].