Added SamplerState

2026-09-05 21:01:52 +00:00 · 2021-02-08 15:36:47 +01:00
parent 11bc63fb04
commit ea140f0532
3 changed files with 300 additions and 0 deletions
@@ -0,0 +1,169 @@
+using System;
+using GlitchyEngine.Math;
+
+namespace GlitchyEngine.Renderer
+{
+	public enum FilterFunction
+	{
+		/// Use point filtering (nearest neighbor) for sampling.
+		Point,
+		/// Use linear interpolation for sampling.
+		Linear,
+		/// Use anisotropic interpolation for sampling.
+		Anisotropic
+	}
+
+	public enum FilterMode
+	{
+		/// Just sample the texture.
+		Default,
+		/// Sample the texture and compares it with a comparison value.
+		Comparison,
+		/// Return the minimum value of the fetched texels.
+		Minimum,
+		/// Return the maximum value of the fetched texels.
+		Maximum
+	}
+
+	public enum ComparisonFunction
+	{
+		/**
+		 * Never pass the comparison.
+		 */
+		Never = 1,
+		/**
+		 * If the source data is less than the destination data, the comparison passes. 
+		 */
+		Less = 2,
+		/**
+		 * If the source data is equal to the destination data, the comparison passes. 
+		 */
+		Equal = 3,
+		/**
+		 * If the source data is less than or equal to the destination data, the comparison passes. 
+		 */
+		LessOrEqual = 4,
+		/**
+		 * If the source data is greater than the destination data, the comparison passes. 
+		 */
+		Greater = 5,
+		/**
+		 * If the source data is not equal to the destination data, the comparison passes. 
+		 */
+		NotEqual = 6,
+		/**
+		 * If the source data is greater than or equal to the destination data, the comparison passes. 
+		 */
+		GreaterOrEqual = 7,
+		/**
+		 * Always pass the comparison. 
+		 */
+		Always = 8
+	}
+
+	public enum TextureAddressMode
+	{
+		/// Tile the texture at every (u,v) integer junction.
+		Wrap = 1,
+		/*
+		 * Tile the texture at every (u,v) integer junction. However it is flipped every other tile.
+		 * Example
+		 * Between 0 and 1 the texture is addressed normally.
+		 * Between 1 and 2 the texture is flipped.
+		 * Between 2 and 3 the texture is addressed normally.
+		 */
+		Mirror,
+		/**
+		 * Texture coordinates outside the range [0.0, 1.0] are set to the texture color at 0.0 or 1.0, respectively.
+		 */
+		Clamp,
+		/**
+		 * Texture coordinates outside the range [0.0, 1.0] are set to the border color.
+		 */
+		Border,
+		/**
+		 * Like a combination of Mirror and Clamp.
+		 * Sample using the absolute value and clamp to 1.0.
+		 */
+		MirrorOnce 
+	}
+
+	public struct SamplerStateDescription
+	{
+		public FilterFunction MinFilter = .Linear;
+		public FilterFunction MagFilter = .Linear;
+		public FilterFunction MipFilter = .Linear;
+
+		public FilterMode FilterMode = .Default;
+		
+		/**
+		 * The function that is used to compare the sampled data against the existing sampled data.
+		 * Only applies if FilterMode is set to FilterMode.Comparison.
+		 */
+		public ComparisonFunction ComparisonFunction = .Never;
+
+		public TextureAddressMode AddressModeU = .Clamp;
+		public TextureAddressMode AddressModeV = .Clamp;
+		public TextureAddressMode AddressModeW = .Clamp;
+		
+		/**
+		 * Offset from the calculated mipmap level.
+		 * For example, if Direct3D calculates that a texture should be sampled at mipmap level 3 and MipLODBias is 2, then the texture will be sampled at mipmap level 5.
+		*/
+		public float MipLODBias = 0;
+		
+		/**
+		 * Lower end of the mipmap range to clamp access to, where 0 is the largest and most detailed mipmap level and any level higher than that is less detailed.
+		 */
+		public float MipMinLOD = float.MinValue;
+		/**
+		 * Upper end of the mipmap range to clamp access to, where 0 is the largest and most detailed mipmap level and any level higher than that is less detailed.
+		 * This value must be greater than or equal to MinLOD. To have no upper limit on LOD set this to a large value such as float.MaxValue.
+		 */
+		public float MipMaxLOD = float.MaxValue;
+
+		/**
+		 * Clamping value used if FilterMode.Anisotropic is specified in the Filters.
+		 * Valid values are between 1 and 16.
+		*/
+		public uint32 MaxAnisotropy = 1; // TODO: we could use a smaller int
+
+		/**
+		 * Border color to use if TextureAddressMode.Border is specified for AddressModeU, AddressModeV, or AddressModeW.
+		 */
+		public ColorRGBA BorderColor = .White;
+	}
+
+	public class SamplerState : RefCounted
+	{
+		protected GraphicsContext _context ~ _?.ReleaseRef();
+
+		protected SamplerStateDescription _desc;
+
+		[Inline]
+		public FilterFunction MinificationFilter => _desc.MinFilter;
+		[Inline]
+		public FilterFunction MagnificationFilter => _desc.MagFilter;
+		[Inline]
+		public FilterFunction MipFilter => _desc.MipFilter;
+		[Inline]
+		public FilterMode FilterMode => _desc.FilterMode;
+
+		protected this(GraphicsContext context)
+		{
+			_context = context..AddRef();
+		}
+
+		public this(GraphicsContext context, SamplerStateDescription desc) : this(context)
+		{
+			_desc = desc;
+
+			PlatformCreateSamplerState();
+		}
+
+		/// Creates the platform specific Sampler State
+		protected extern void PlatformCreateSamplerState();
+
+		public extern void Bind(uint32 slot = 0);
+	}
+}