/Utilities/Graphics/ShaderFeatures/ParallaxMapShaderFeature.cs

using System.Collections.Generic;

using System.IO;



namespace Delta.Utilities.Graphics.ShaderFeatures

{

	/// <summary>

	/// ParallaxMap shader feature

	/// Note: add some flags where the parallax height map is coming from

	/// (lightmap (currently), diffuse, normal map, extra map, etc.)

	/// </summary>

	public class ParallaxMapShaderFeature : IShaderFeature

	{

		#region ParallaxAmount (Public)

		/// <summary>

		/// Parallax mapping is usually used in combination with normal mapping,

		/// but you can use it own its own. It needs an extra height map (usually

		/// just the light map or normal map extra alpha color channel) for even

		/// cooler depth effects on the texture. Adds about 2 instructions, but

		/// even if that overhead is ok, also additional work at the artist side

		/// is needed, not only to create the extra height/bump map, but also to

		/// fine tune the parallax amount to look nice. The height map should be

		/// as blurry as possible, high variations will cause parallax glitches.

		/// </summary>

		public float ParallaxAmount = ShaderConstants.DefaultParallaxAmount;

		#endregion



		#region ShaderFeature (Public)

		/// <summary>

		/// Which shader feature flag is this ShaderFeature class using?

		/// Important for loading this file via ShaderData.LoadShaderFeature.

		/// Each flag should obviously only have one class for it!

		/// </summary>

		public ShaderFeatureFlags ShaderFeature

		{

			get

			{

				return ShaderFeatureFlags.ParallaxMap;

			}

		}

		#endregion



		#region RequiredShaderFeatures (Public)

		/// <summary>

		/// Which shader feature flags are required for this ShaderFeature.

		/// Very important for creating of a new ShaderFeature.

		/// </summary>

		public ShaderFeatureFlags RequiredShaderFeatures

		{

			get

			{

				// Note: We need nothing for parallax, but it is usually combined

				// with many other flags, most importantly NormalMap to look cool.

				// Currently we use the LightMap alpha channel for the parallax, so

				// we always need those two flags together.

				return ShaderFeatureFlags.LightMap; //.Basic;

			}

		}

		#endregion



		#region Parameters (Public)

		/// <summary>

		/// Parameters as a dictionary, will be generated on the fly when

		/// requested.

		/// </summary>

		public Dictionary<string, object> Parameters

		{

			get

			{

				Dictionary<string, object> ret = new Dictionary<string, object>();

				ret.Add("ParallaxAmount", ParallaxAmount);

				return ret;

			}

		}

		#endregion



		#region Constructors

		/// <summary>

		/// Create parallax shader feature

		/// </summary>

		public ParallaxMapShaderFeature()

		{

		}



		/// <summary>

		/// Create parallax shader feature

		/// </summary>

		public ParallaxMapShaderFeature(BinaryReader reader)

		{

			Load(reader);

		}

		#endregion



		#region ISaveLoadBinary Members

		/// <summary>

		/// Load this ShaderFeature from a binary data stream.

		/// </summary>

		public void Load(BinaryReader reader)

		{

			ParallaxAmount = reader.ReadSingle();

		}



		/// <summary>

		/// Save this ShaderFeature to a binary data stream.

		/// </summary>

		public void Save(BinaryWriter writer)

		{

			writer.Write(ParallaxAmount);

		}

		#endregion

	}

}