NSprites - Unity DOTS Sprite Rendering Package

This framework provides sprite rendering system compatible with Entities package (unity ECS).

Note: Currently supports only Entities 0.51.x. Support for 1.0 is the next development stage.

Basically it sync whatever entity component you want with GPU data to perform instanced rendering. As a result all entities with same Material can be rendered with single DrawCall.

Basic API

For more detailed information please read project's wiki.

// registrate components as properties at assembly level anywhere in project
[assembly: InstancedPropertyComponent(typeof(WorldPosition2D), "_pos2D", PropertyFormat.Float2)]
[assembly: InstancedPropertyComponent(typeof(SpriteColor), "_color", PropertyFormat.Float4)]

// registrate render with ID, Material, capacity data and set of properties
var renderSystem = World.GetSystem<SpriteRenderingSystem>();
// don't registrate same renderID
renderSystem.RegisterRender
(
    renderID,
    material,   // material with [Enable GPU Instancing] enabled and shader supporting instancing
    null,       // override for MaterialPropertyBlock if needed
    128,        // initial ComputeBuffers capacity
    128,        // minimal capacity step for ComputeBuffers
    "_pos2D",   // world 2D position property
    "_color"    // color property
);

// initialize sprite entity with all needed components for rendering
entityManager.AddSpriteRenderComponents(spriteEntity, renderID);
// WorldPosition2D and SpriteColor are example client's components
entityManager.AddComponentData(new WorldPosition2D());          
entityManager.AddComponentData(new SpriteColor(Color.White));

Also shader you're using should be compatible with instancing. Check my example shader gist. The main idea is to use StructuredBuffer<T> _propertyName. Though it is possible to use instanced properties with ShaderGraph, so you may try your option. For local example shader main part can look like:

#if defined(UNITY_INSTANCING_ENABLED) || defined(UNITY_PROCEDURAL_INSTANCING_ENABLED) || defined(UNITY_STEREO_INSTANCING_ENABLED)
StructuredBuffer<int> _propertyPointers;
StructuredBuffer<float2> _pos2D;
StructuredBuffer<float4> _color;
#endif
// ...
Varyings UnlitVertex(Attributes attributes, uint instanceID : SV_InstanceID)
{
    // ...    
#if defined(UNITY_INSTANCING_ENABLED) || defined(UNITY_PROCEDURAL_INSTANCING_ENABLED) || defined(UNITY_STEREO_INSTANCING_ENABLED)
    int propPointer = _propertyPointers[instanceID]; // this is internal package property to point right data during component sync
    float2 pos = _pos2D[propPointer];
    float4 color = _color[propPointer];
#else
    //fallback if somehow instancing failed
    float2 pos = float2(0,0);
    float4 color = flaot4(1,1,1,1);
#endif
    // ...
}

How it works

SpriteRenderingSystem sync registered entity components with ComputeBuffers to send data to GPU and then renders entities with Graphics.DrawMeshInstancedProcedural. System also controls how ComputeBuffers reallocates if capacity exceeds. Sprites are simple entities with no limits what components you use.

Installation

Requirements

• Unity 2020.3.x / 2021.3.x
• Entities 0.51.x

Install via Package Manager

• Window -> Package Manager -> + button -> Add package from git url
• Paste https://github.com/Antoshidza/NSprites.git

Install via git submodule

• cd to your project's /Packages folder
• git submodule https://github.com/Antoshidza/NSprites.git

Support 👍 Contribute 💻 Contanct 💬

I wish this project will be helpful for any ECS early adopters! So feel free to send bug reports / pull requests, start discussions / critique, those all are highly appreciated! You can contact with my discord account!