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Question Entities Graphics and custom shader properties issue

Discussion in 'Graphics for ECS' started by grogzgr, Mar 7, 2023.

  1. grogzgr


    Jan 10, 2014
    I have a custom URP Unlit Shader created in Shader Graph with boolean property that I want to set on a per instance basis in a System. From the documentation it seems like it should be a straight forward thing to do, but try as I might, it's not working for me.

    If needed I can post snippets of code, but hopefully the following description will trigger someone to say "oh yeah, you need to do .... "

    I have created a managed prefab, used the Baker to convert it to an entity, then used this entity to instantiate multiple entities using EntityManager.Instantiate() . The material on the prefab uses a custom URP Unlit shader with a custom property that is "Exposed" and has the "Shader Declaration" set to "Hybrid Per Instance". I created the IComponentData struct with the MaterialProperty set to the "Reference" name of my exposed property.
    I have done this as per the manual page:

    I am setting the property in a ISystem using my custom aspect. The component reference in the aspect is declared as a RefRW, and I am setting the value using:

    Code (CSharp):
    1. myAspect.myComponent.ValueRW.Activated = 1f;
    In the inspector I can see that the property is being set on the Entity instance, but it does not seem to be having an effect on the shader.

    What am I missing?

    Unity version: 2022.2.0f1
    Entities: 1.0.0-pre.15
    Entities Graphics: 1.0.0-pre.15
    Universal RP: 14.0.4
  2. suity447


    Oct 18, 2022
    I am not 100 % sure but I seem to remember that boolean properties can have some unexpected behaviours. It seems that your IComponentData is a float? If it is a bool in the shader graph maybe change it to an float/int/uint and add a comparison block in the graph to output a bool.
    grogzgr likes this.
  3. grogzgr


    Jan 10, 2014
    Well you got it. According to what I read a boolean in a shader should be set by a float in a IComponentData, but this turns out not to be the case currently.

    So I did as you suggested and replaced the boolean property in the Shader with a float property. Then I changed the Predicate in the Branch node to be fed the "Out" of a new Comparison Node, with the Comparison node checking if the new float property was 1 or 0. This just feels wrong, and a hack, but it works so ...

  4. JussiKnuuttila


    Unity Technologies

    Jun 7, 2019
    Unity's shader system does not support booleans, and shaders in general don't really support booleans as input/output data, only as results of computations done inside the shader. Using an int or a float as you have done is the proper solution.