#NOTE This repository is not currently maintained however is left here for your reference

The free edition of BovineLabs Savanna Saving for Dots

Support: https://discord.gg/RTsw6Cxvw3

Savanna is a saving system for Unity’s Entities package. If you do not use Entities in your project then this package is not for you.

The minimum requirements for the package is

• Entities: 1.2.0-pre.12 and newer
• BovineLabs Core: 1.2.12 and newer (available https://gitlab.com/tertle/com.bovinelabs.core or https://openupm.com/packages/com.bovinelabs.core/)

The samples also require

• Entities Graphics: 1.2.0-pre.12 and newer
• Universal RP

To make a IComponentData or IBufferElement savable all that is required is to add the Save attribute to the to component. This can be applied to IComponentData, IBufferElement and and tag components that have IEnableableComponent.

[Save]
public struct TestComponentData : IComponentData
{    
    public int Value;
}

[Save]
public struct TestBufferElement : IBufferElement
{    
    public float Value;
}

[Save]
public struct TestTag : IComponentData, IEnableableComponent
{    
}

Saving managed components is not supported and it's advised to avoid needing to do this however if this is something you need it is possible by adding your own custom saving into the pipeline.

If you don’t have access to the assembly that has a component you want to serialize, for example a component inside a Unity package, it is still possible to save the component by adding it via the save builder.

If you don’t want to save an entire component you can use the SaveIgnoreAttribute to fields and they will be ignored when deserializing.

[Save]
public struct TestComponentData : IComponentData
{    
    public int Value0;
    public int Value1;
    
    [SaveIgnore] 
    public byte Value2;
}

This attribute will still cause the entire component to be serialized and will not reduce file size; instead when deserialized the data will simply be ignored. This is done for performance and also to allow you to change your mind. If you wanted the field to no longer be ignored you could safely remove the attribute and existing saves will have the data and deserialize correctly.

It is more performant to group all fields that have this attribute on them together at either the top or bottom of the struct. This will minimize the number of MemCpyReplicates that need to be executed on deserializing. Each group of serializable fields requires a separate copy so only a single call is required when they are all grouped together.

If a IComponentData or IBufferElement is marked to be saved and inherits from the IEnableableComponent, then the enabled state of the component will also be saved along side the component and applied back on loading.

The default workflow for saving games is to use the SaveManager helper struct which manages and various state for you.

A simple example of setting up a system with SaveManager.

[BurstCompile]
[UpdateAfter(typeof(SceneSystemGroup))]
[UpdateInGroup(typeof(InitializationSystemGroup))]
public partial struct SaveSystem : ISystem
{
    private SaveManager saveManager;

    public void OnCreate(ref SystemState state)
    {
        var saveBuilder = new SaveBuilder(ref state);
        this.saveManager = new SaveManager(ref state, saveBuilder);
    }

    public void OnDestroy(ref SystemState state)
    {
        this.saveManager.Dispose();
    }

    [BurstCompile]
    public void OnUpdate(ref SystemState state)
    {
        // Save save data to a NativeList. Usually written to disk
        // state.Dependency = this.saveManager.Save(ref savedData, state.Dependency);

        // Load existing save data. Usually from disk
        // state.Dependency = this.saveManager.Load(saveData, state.Dependency);

        // Save a sub scene then close it
        // state.Dependency = this.saveManager.SaveClose(saveSceneEntity, state.Dependency);

        // Open a sub scene and apply existing save data
        // state.Dependency = this.saveManager.OpenLoad(saveSceneEntity, state.Dependency);

        state.Dependency = this.saveManager.Update(state.Dependency);
    }
}