Sampler States

Sampler states control how textures are sampled in shaders, how they’re filtered and addressed.

Modern GPUs allow binding of 128 textures in a shader, however you are limited to only 16 bound samplers.
This is generally more than enough if you reuse samplers for multiple textures.

Sampler states are defined as you normally would in HLSL, but should be annotated with the desired options.

Texture2D MyCoolTexture;
Texture2D MyOtherCoolTexture;
SamplerState MyPixelySampler < Filter( Point ); >;

// Using the samplers
float4 color1 = MyCoolTexture.Sample( MyPixelySampler, uv );
float4 color2 = MyOtherCoolTexture.Sample( MyPixelySampler, uv );

Annotations

Annotation	Description	Possible Values
Filter	Filtering mode used for texture sampling.	Point, Linear, Anisotropic
AddressU	Texture coordinate addressing mode for the U direction.	Wrap, Mirror, Clamp, Border, Mirror_Once
AddressV	Texture coordinate addressing mode for the V direction.	Wrap, Mirror, Clamp, Border, Mirror_Once
AddressW	Texture coordinate addressing mode for the W direction.	Wrap, Mirror, Clamp, Border, Mirror_Once
MaxAniso	Maximum anisotropy level allowed for anisotropic filtering.	Integer value (e.g., 2, 4, 8, 16, etc.)

Filters

Enum	Description
Point	Same as MinMagMipPoint
Bilinear	Same as MinMagLinearMipPoint
Trilinear	Same as MinMagMipLinear
Anisotropic	Anisotropic filtering, controlled by MaxAniso
MinMagMipPoint	Minify/magnify/mipmap using point sampling.
MinMagPointMipLinear	Minify/magnify using point sampling, mipmap using linear interpolation.
MinPointMagLinearMipPoint	Minify using point sampling, magnify using linear sampling, mipmap using point sampling.
MinPointMagMipLinear	Minify using point sampling, magnify using point sampling, mipmap using linear interpolation.
MinLinearMagMipPoint	Minify using linear interpolation, magnify using point sampling, mipmap using point sampling.
MinLinearMagPointMipLinear	Minify using linear interpolation, magnify using point sampling, mipmap using linear interpolation.
MinMagLinearMipPoint	Minify/magnify using linear sampling, mipmap using point sampling.
MinMagMipLinear	Minify/magnify/mipmap using linear interpolation.
ComparisonMinMagMipPoint	Comparison minify/magnify/mipmap using point sampling.
ComparisonMinMagPointMipLinear	Comparison minify/magnify using point sampling, mipmap using linear interpolation.
ComparisonMinPointMagLinearMipPoint	Comparison minify using point sampling, magnify using linear sampling, mipmap using point sampling.
ComparisonMinPointMagMipLinear	Comparison minify using point sampling, magnify using point sampling, mipmap using linear interpolation.
ComparisonMinLinearMagMipPoint	Comparison minify using linear interpolation, magnify using point sampling, mipmap using point sampling.
ComparisonMinLinearMagPointMipLinear	Comparison minify using linear interpolation, magnify using point sampling, mipmap using linear interpolation.
ComparisonMinMagLinearMipPoint	Comparison minify/magnify using linear sampling, mipmap using point sampling.
ComparisonMinMagMipLinear	Comparison minify/magnify/mipmap using linear interpolation.
ComparisonAnisotropic	Comparison anisotropic filtering.

Common Samplers

Here are some common predefined sampler states you can use in your shaders.

Sampler State	Description
g_sAniso	Anisotropic filtering with a maximum anisotropy level of 8.
g_sBilinearClamp	Bilinear filtering with texture coordinate addressing mode set to clamp for U, V, and W directions.
g_sTrilinearWrap	Trilinear filtering with texture coordinate addressing mode set to wrap for U, V, and W directions.
g_sTrilinearClamp	Trilinear filtering with texture coordinate addressing mode set to clamp for U, V, and W directions.
g_sPointClamp	Point filtering with texture coordinate addressing mode set to clamp for U, V, and W directions.
g_sPointWrap	Point filtering with texture coordinate addressing mode set to wrap for U and V directions, and clamp for W direction.

CreateTexture2D & Tex2D macros create and sample coupled textures and samplers, this is how older graphics APIs (DX9) and should be avoided due to it’s limitations.