How can I set _ObjectId in DOTS?

Unity Engine
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1

I need to set _ObjectId for some shader to work. I tried using material overrides but it doesn’t work.

[MaterialProperty("_ObjectId")]
public struct MaterialPropertyObjectId : IComponentData
{
    public int Value;

    public MaterialPropertyObjectId(int value)
    {
        Value = value;
    }
}

The _ObjectId is always zero:
9919188--1434345--upload_2024-7-2_11-55-22.png

9919188--1434345--upload_2024-7-2_11-55-22.png
9919188--1434345--upload_2024-7-2_11-55-22.png

2

Basically, I want the DOTS equivalent of MaterialPropertyBlock.SetInteger().

3

It doesn’t appear that that particular shader variable is made to be DOTS-instancing compatible. Your options are to either modify the shader or make a new material and modify that.

4

How do I modify the shader to make it compatible? I tried using Properties but it doesn’t work. I’ve read that material overrides only works with Shader Graph but I’m not sure about that.

5

They works just fine with properly manually written shader.

1 Like
6

Does you have somehting like this in your shader?

float _ObjectId;

#ifdef UNITY_DOTS_INSTANCING_ENABLED
    UNITY_DOTS_INSTANCING_START(MaterialPropertyMetadata)
        UNITY_DOTS_INSTANCED_PROP(float, _ObjectId)
    UNITY_DOTS_INSTANCING_END(MaterialPropertyMetadata)

    #define _ObjectId  UNITY_ACCESS_DOTS_INSTANCED_PROP_WITH_DEFAULT(float,  _ObjectId)
#endif

And you have instance id set, either manually or through Unity macro, for vertex input struct (if you access instanced property in vertex function) and/or for fragment input struct (if you access instanced property in fragment function) like
UNITY_VERTEX_INPUT_INSTANCE_ID
And have set it in the beginning (before any instanced property usage) of your vertex/fragment function?
UNITY_SETUP_INSTANCE_ID(IN);
(And if you access in fragment shader you properly transfer it from vertex shader)
UNITY_TRANSFER_INSTANCE_ID(IN, OUT);

1 Like