using UnityEngine;

using Raymarcher.Materials;

// Inherit from RMMaterialBase to create a scriptableObject. Add 'CreateAssetMenu' attribute to display this object in the Project window.
[CreateAssetMenu(fileName = nameof(MatTestScriptableBase), menuName = "Custom Raymarcher Material")]
public sealed class MatTestScriptableBase : RMMaterialBase
{
 public MaterialData materialData = new MaterialData();

 [System.Serializable]
 public class MaterialData
 {
  public float height = 0;
  public float blend = 0.5f;
  public Color colorBottom = Color.red;
  public Color colorTop = Color.blue;
 }

 // We will come back to this method later!
 public override RMMaterialDataBuffer MaterialCreateDataBufferInstance()
 {
  return null;
 }
}

using System;
using System.Runtime.InteropServices;
using System.Collections.Generic;

using UnityEngine;

using Raymarcher.Materials;

public sealed class MatTestDataBuffer : RMMaterialDataBuffer
{
 // You can allocate any data in the classes constructor if needed
 public MatTestDataBuffer(in RMMaterialIdentifier materialIdentifier) : base(materialIdentifier)
 {}

 [Serializable, StructLayout(LayoutKind.Sequential)]
 public struct MaterialDataContainer
 {
  public float height; // 4 bytes (1x float)
  public float blend; // 4 bytes (1x float)
  public Vector3 colorBottom; // rgb(no alpha) 12 bytes (3x floats)
  public Vector3 colorTop; // rgb(no alpha) 12 bytes (3x floats)
  // Total stride = 8x floats = 32 bytes = 256 bits
 }

 // Declare an array of buffer containers - each element represents one material instance
 public MaterialDataContainer[] materialDataContainer;

 // Must always returns the buffer container ^
 public override Array GetComputeBufferDataContainer => materialDataContainer;

 // This is called everytime a new material instance is registered. Please do not forget to allocate your container with the number of material instances of this type
 public override void InitializeDataContainerPerInstance(in IReadOnlyList<RMMaterialBase> materialInstances, in bool sceneObjectsAreUsingSomeInstances, in bool unpackedDataContainerDirective)
 {
  base.InitializeDataContainerPerInstance(materialInstances, sceneObjectsAreUsingSomeInstances, unpackedDataContainerDirective);
  // Allocate buffer array to material instances
  materialDataContainer = new MaterialDataContainer[materialInstances.Count];
 }

 // As mentioned in the struct container = 8x size of floats. This is required for the computeBuffer.
 public override (int dataLength, int strideSize) GetComputeBufferLengthAndStride()
  => (materialDataContainer.Length, sizeof(float) * 8); // Or use 'Marshal.SizeOf<YourDataStructureType>()'

 // This is called every frame for every material instance of this type
 public override void SyncDataContainerPerInstanceWithMaterialInstance(in int iterationIndex, in RMMaterialBase materialInstance)
 {
  // Cast your material type (the type is always safe as further material filtering is done before syncing)
  MatTestScriptableBase material = (MatTestScriptableBase)materialInstance;

  MaterialDataContainer container;

  // Sync all desired fields with the casted material instance
  container.height = material.materialData.height;
  container.blend = material.materialData.blend;
  Color colorTemp = material.materialData.colorBottom;
  container.colorBottom = new Vector3(colorTemp.r, colorTemp.g, colorTemp.b);
  colorTemp = material.materialData.colorTop;
  container.colorTop = new Vector3(colorTemp.r, colorTemp.g, colorTemp.b);

  // Sync every buffer element with individual material instance
  materialDataContainer[iterationIndex] = container;
 }
}

using Raymarcher.Materials;

public sealed class MatTestIdentifier : RMMaterialIdentifier
{
 // Could be any name. Just for a visual representation
 public override string MaterialTypeName => "Custom Height Gradient Material";

 // Clone the MaterialDataContainer data in the MatTestDataBuffer
 public override MaterialUniformField[] MaterialUniformFieldsPerInstance
  => new MaterialUniformField[]
  {
   // !! Note that the order of declaration is exactly the same as in the MatTestDataBuffer.MaterialDataContainer !!
   new MaterialUniformField(nameof(MatTestDataBuffer.MaterialDataContainer.height), MaterialUniformType.Float),
   new MaterialUniformField(nameof(MatTestDataBuffer.MaterialDataContainer.blend), MaterialUniformType.Float),
   new MaterialUniformField(nameof(MatTestDataBuffer.MaterialDataContainer.colorBottom), MaterialUniformType.Float3),
   new MaterialUniformField(nameof(MatTestDataBuffer.MaterialDataContainer.colorTop), MaterialUniformType.Float3)
  };

 // You can load the main method's content from resources/ text file or write it directly as a string.
 // Note the method's datatype and parameters = these are constantly set as a main 'caller'
 public override MaterialMethodContainer MaterialMainMethod
  => new MaterialMethodContainer("CalculateHeightGradient",
@"

// Here comes your shading code. Hence the naming conventions!
// Have a look at the Raymarcher's core shading library for proper use of 'Ray' struct and other properties/helpers:
// Raymarcher/CG/CoreLibrary/RMHLSL_Input.cginc
// and
// Raymarcher/CG/CoreLibrary/RMHLSL_Common.cginc

half4 CalculateHeightGradient(in MaterialDataContainer data, in Ray ray, half4 sdfRGBA)
{
 half3 color = lerp(data.colorBottom, data.colorTop, smoothstep(data.height - data.blend, data.height + data.blend, ray.p.y));
 return half4(color, 1);
}

");

 // Could be any, but the name must match with the type in the shader, hence the 'in MaterialDataContainer data' parameter above...
 public override string MaterialDataContainerTypePerInstance => nameof(MatTestDataBuffer.MaterialDataContainer);

 // This material type is not using any textures
 public override bool MaterialIsUsingTexturesPerInstance => false;
}

// ... MatTestScriptableBase code ...
public override RMMaterialDataBuffer MaterialCreateDataBufferInstance()
 => new MatTestDataBuffer(new MatTestIdentifier());