How to use mat

[yuxinabc]

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Describe the bug
I am not sure if this is a bug, I would like to ask how to use mat

To Reproduce

1. Writing a .mat file

material {
    name : EmissiveMaterial,
    shadingModel : unlit,
    parameters : [
        { type : float3, name : emissiveColor },
        { type : float, name : emissiveIntensity }
    ]
}
fragment {
    void material(inout MaterialInputs material) {
        prepareMaterial(material);
       // Correct the parameter reference to ensure the use of the materialParams structure
        material.emissive.rgb = materialParams.emissiveColor * materialParams.emissiveIntensity;
    }
}

2. Execute the matc command
   ./matc -p mobile -a opengl -o emissive.filamat emissive.mat

3. Load the .filament file and apply

readCompressedAsset("filamat/emissive.filamat").let {
            modelViewer.updateFilamat(it)
        }
fun updateFilamat(buffer: ByteBuffer) {
        // 3. Load the material in the application
        val material = Material.Builder().payload(buffer, buffer.remaining()).build(engine)
         // 4. Apply the material to the model's mesh
        val rendererManager = engine.renderableManager
        val entities = asset!!.entities
        for (entity in entities) {
            if (rendererManager.hasComponent(entity)) {
                val renderer = rendererManager.getInstance(entity)
                // renderer
                val materialCount = rendererManager.getPrimitiveCount(renderer)
                for (i in 0 until materialCount) {
                    val materialInstance1 = rendererManager.getMaterialInstanceAt(renderer, i)
                    val name = unicode(materialInstance1.name)
                    if (name.startsWith("light bead")) {
                        // Create a material instance
                        val materialInstance = material.createInstance()
                     // Set emissive color and intensity
                        materialInstance.setParameter(
                            "emissiveColor", Colors.RgbType.SRGB, 1.0f, 0.0f, 0.0f
                        )  // Red
                        materialInstance.setParameter("emissiveIntensity", 5.0f) // 强度
                        // Apply the material instance
                        rendererManager.setMaterialInstanceAt(
                            renderer, i, materialInstance
                        )
                    }
                }
            }
        }
    }

I made sure that the setMaterialInstanceAt method was executed

Expected behavior
Each bead should have its own emissive color, but the actual effect is white.

Screenshots

[PsycoTodd]

First, change your shader to hard coded value, in material.emissive.rgb = vec3(0, 1, 0) to see if you get green result. Since white is a default color, it may affect your judgement.

Second. your material instance should just create only once during rendering, if you add the entity into scene, you just create the material once and attach to the entity.

You can update using setparamters each frame.

[yuxinabc]

Thank you for the answer, I'll give it a try.