Unity: Difference between revisions

 
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All loading of streaming assets should be done in a background thread. See [https://wiki.davidl.me/view/C_Sharp#Multithreading C# Multithreading] for more details on multithreading.<br>
All loading of streaming assets should be done in a background thread. See [https://wiki.davidl.me/view/C_Sharp#Multithreading C# Multithreading] for more details on multithreading.<br>
I've found that Unity's job system doesn't perform as well as C#'s ThreadPool when stressed with thousands of small tasks so I recommend using C# APIs over Unity APIs whenever possible.<br>
I've found that Unity's job system doesn't perform as well as C#'s ThreadPool when stressed with thousands of small tasks so I recommend using C# APIs over Unity APIs whenever possible.<br>
[https://wiki.davidl.me/view/C_Sharp#Multithreading Ciela Spike's Thread Ninja] may be used to run coroutines in the background when you only need a single, but complex, task.<br>
[https://assetstore.unity.com/packages/tools/thread-ninja-multithread-coroutine-15717 Ciela Spike's Thread Ninja] may be used to run coroutines in the background when you only need a single, but complex, task.<br>
Much of Unity's API such as <code>new Mesh()</code> and <code>new Texture2D()</code> cannot be called from background threads. I suggest caching textures as <code>byte[]</code> or <code>Color32[]</code> which can then be loaded with [https://docs.unity3d.com/ScriptReference/Texture2D.LoadRawTextureData.html <code>Texture2D.LoadRawImageData()</code>]. Similarly, you can cache a Mesh by caching a struct of vertices, triangles, normals, and tangents.
Much of Unity's API for GPU assets such as <code>new Mesh()</code> and <code>new Texture2D()</code> cannot be called from background threads.
I suggest caching textures in system memory as <code>byte[]</code> or <code>Color32[]</code> which can then be loaded with [https://docs.unity3d.com/ScriptReference/Texture2D.LoadRawTextureData.html <code>Texture2D.LoadRawImageData()</code>]. Similarly, you can hold a Mesh in system memory by using a struct of vertices, triangles, normals, and tangents.


===Instancing===
===Instancing===
If you need multiple instances of the same object, make sure that the material is instanced so that all objects only consume one draw call.<br>
If you need multiple instances of the same object, make sure that the material is instanced so that all objects only consume one draw call.<br>
See [https://docs.unity3d.com/Manual/GPUInstancing.html Unity: GPUInstancing].<br>
See [https://docs.unity3d.com/Manual/GPUInstancing.html Unity: GPUInstancing].<br>
Do not attach scripts to thousands of objects. Instead use one script on one object.<br>
Do not attach scripts to thousands of objects. Instead use one script to control all instanced objects.<br>


====Merging Meshes====
====Merging Meshes====
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Be aware of the limitations of using a single draw call though; transparency can become tricky.
Be aware of the limitations of using a single draw call though; transparency can become tricky.


You can use a compute shader to animate and move the objects instead of using Unity scripts.   
After merging a mesh, you can use a compute shader to animate and move the objects instead of using Unity scripts.   
The compute shader edits a single compute buffer which can be read by your vertex or geometry shader without passing data back to the CPU.
The compute shader edits a single compute buffer which can be read by your vertex or geometry shader without passing data back to the CPU.