GetComponent
GetComponent retrieves the underlying component data for a given entity.
func GetComponent[T metadata.Component](worldCtx WorldContext, id entity.ID) (*T, error)
Example
import "pkg.world.dev/world-engine/cardinal"
health, err := cardinal.GetComponent[Health](worldCtx, id)
Parameters
| Parameter | Type | Description |
|---|
T | type parameter | A registered component struct that implements the Name method |
worldCtx | WorldContext | A WorldContext object passed in to your system or Query definition |
id | EntityID | The ID of the entity from which to retrieve the component data. |
Return Values
| Type | Description |
|---|
T | The retrieved component data. |
error | An error indicating any issues during retrieval. |
SetComponent
SetComponent sets the component data for a given entity.
func SetComponent[T metadata.Component](worldCtx WorldContext, id entity.ID, component *T) error
Example
import "pkg.world.dev/world-engine/cardinal"
newHealth := Health{Amount: 45, Capacity: 100}
err := cardinal.SetComponent[Health](worldCtx, id, newHealth)
Parameters
| Parameter | Type | Description |
|---|
T | type parameter | A registered component struct that implements the Name method |
worldCtx | WorldContext | A WorldContext object passed in to your system or query definition |
id | EntityID | Entity ID of the entity to set the component data for. |
component | T | Component value to set for the entity. |
Return Value
| Type | Description |
|---|
error | An error indicating any issues during the operation. |
UpdateComponent
UpdateComponent enables modification of the underlying component data in a single function call. Update uses Get and Set under the hood.
func UpdateComponent[T metadata.Component](worldCtx WorldContext, id entity.ID, fn func(*T) *T) error
Example
import "pkg.world.dev/world-engine/cardinal"
err := cardinal.UpdateComponent[Health](worldCtx, id, func(h *Health) *Health {
h.Amount -= 10
return r
})
Parameters
| Parameter | Type | Description |
|---|
T | type parameter | A registered component struct that implements the Name method |
worldCtx | WorldContext | A WorldContext object passed in to your system or query definition |
id | EntityID | ID of the entity to perform the component update on. |
fn | func(*T) *T | Function that modifies the component’s value. |
Return Value
| Type | Description |
|---|
error | An error indicating any issues during the operation. |
RemoveComponentFrom
RemoveComponentFrom removes the component from the given entity. An error will be returned if the entity does not have the component.
func RemoveComponentFrom[T metadata.Component](worldCtx WorldContext, id entity.ID) error
Example
import "pkg.world.dev/world-engine/cardinal"
target := EntityID(10)
err := cardinal.RemoveComponentFrom[Health](worldCtx, target)
Parameters
| Parameter | Type | Description |
|---|
T | type parameter | A registered component struct that implements the Name method |
worldCtx | WorldContext | A WorldContext object passed in to your system or query definition |
id | EntityID | Entity ID of the entity to remove the component from. |
Return Value
| Type | Description |
|---|
error | Returns an error if the operation encounters an issue. |
AddComponentTo
AddComponentTo adds the component to a given entity. An error will be returned if the entity already has the component.
func AddComponentTo[T metadata.Component](worldCtx WorldContext, id entity.ID) error
Example
import "pkg.world.dev/world-engine/cardinal"
target := EntityID(40)
err := cardinal.AddComponentTo[Health](worldCtx, target)
Parameters
| Parameter | Type | Description |
|---|
T | type parameter | A registered component struct that implements the Name method |
worldCtx | WorldContext | A WorldContext object passed in to your system or query definition |
id | EntityID | Entity ID of the entity to add the component to. |
Return Value
| Type | Description |
|---|
error | Returns an error if the operation encounters an issue. |
