Using texture arrays in shaders

Similar to regular 2D textures (Texture2D class, sampler2D in shaders), cube maps (Cubemap class, samplerCUBE in shaders), and 3D textures (Texture3D class, sampler3D in shaders), Unity also supports 2D texture arrays.

Since texture arrays do not work on all platforms, shaders need to use an appropriate compilation target or feature requirement to access them. The minimum shader model compilation target that supports texture arrays is 3.5, and the feature name is 2darray.

Use these macros to declare and sample texture arrays:

• UNITY_DECLARE_TEX2DARRAY(name) declares a texture array sampler variable inside HLSL code.
• UNITY_SAMPLE_TEX2DARRAY(name,uv) samples a texture array with a float3 UV; the z component of the coordinate is an array element index.
• UNITY_SAMPLE_TEX2DARRAY_LOD(name,uv,lod) samples a texture array with an explicit mipmap level.

Примеры

The following shader example samples a texture array using object space vertex positions as coordinates:

Shader "Example/Sample2DArrayTexture"
{
    Properties
    {
        _MyArr ("Tex", 2DArray) = "" {}
        _SliceRange ("Slices", Range(0,16)) = 6
        _UVScale ("UVScale", Float) = 1.0
    }
    SubShader
    {
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // texture arrays are not available everywhere,
            // only compile shader on platforms where they are
            #pragma require 2darray
            
            #include "UnityCG.cginc"

            struct v2f
            {
                float3 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            float _SliceRange;
            float _UVScale;

            v2f vert (float4 vertex : POSITION)
            {
                v2f o;
                o.vertex = mul(UNITY_MATRIX_MVP, vertex);
                o.uv.xy = (vertex.xy + 0.5) * _UVScale;
                o.uv.z = (vertex.z + 0.5) * _SliceRange;
                return o;
            }
            
            UNITY_DECLARE_TEX2DARRAY(_MyArr);

            half4 frag (v2f i) : SV_Target
            {
                return UNITY_SAMPLE_TEX2DARRAY(_MyArr, i.uv);
            }
            ENDCG
        }
    }
}

См. также

• Introduction To Textures in Direct3D documentation.
• Array Textures in OpenGL Wiki.

• 2018–03–20 Page amended
• Shader #pragma directives added in Unity 2018.1