UnityGame/Library/PackageCache/com.unity.shadergraph/Documentation~/Sample-Virtual-Texture-Node.md

Sample Virtual Texture Node

Description

Samples a Virtual Texture and returns up to four Vector 4 color values for use in the shader. You can use the UV input to override the UV coordinate. The Sample Virtual Texture node takes one UV coordinate as the input, and uses that UV coordinate to sample all of the textures in the Virtual Texture.

If you want to use the Sample Virtual Texture node to sample normal maps, navigate to each layer that you want to sample as a normal map, open the Layer Type drop-down menu, and select Normal.

By default, you can only use this node in the fragment shader stage. For more information about how to use this node, or how to configure it for use in the vertex shader stage, see Using Streaming Virtual Texturing in Shader Graph.

If you disable Virtual Texturing in your project, this node works the same way as the Sample 2D Texture Node, and performs standard 2D sampling on each texture.

You must connect a Sample Virtual Texture node to a Virtual Texture property for the Shader Graph Asset to compile. If you don't connect the node to a property, an error appears, indicating that the node requires a connection.

For information about Streaming Virtual Texturing, see Streaming Virtual Texturing.

Ports

Name	Direction	Type	Binding	Description
UV	Input	Vector 2	UV	The UV coordinate.
VT	Input	Virtual Texture	None	The Virtual Texture to sample. Must be connected to a Virtual Texture property.
Out	Output	Vector 4	None	The output value of layer 1 as RGBA.
Out2	Output	Vector 4	None	The output of layer 2 as RGBA.
Out3	Output	Vector 4	None	The output of layer 3 as RGBA.
Out4	Output	Vector 4	None	The output of layer 4 as RGBA.

Settings

The Sample Virtual Texture node has several settings available for you to specify its behavior. These settings work in combination with any scripts you might have set up in your project. To view the settings, select the node with the Graph Inspector open. For more information, see Streaming Virtual Texturing.

Name	Type	Options	Description
Lod Mode	Dropdown	Automatic, Lod Level, Lod Bias, Derivatives	Sets the specific Lod mode to use when sampling the textures.
Quality	Dropdown	Low, High	Sets the quality mode to use when sampling the textures.
Automatic Streaming	Toggle	Enabled/Disabled	Determines whether the node uses automatic streaming or manual streaming.
Enable Global Mip Bias	Toggle	Enabled/Disabled	Enables the global mipmap bias that Unity automatically imposes at runtime. Unity sets this bias during certain dynamic resolution scaling algorithms to improve detail reconstruction.
Layer 1 Type	Dropdown	Default, Normal	The texture type of layer 1.
Layer 2 Type	Dropdown	Default, Normal	The texture type of layer 2.
Layer 3 Type	Dropdown	Default, Normal	The texture type of layer 3. This option only appears if the Virtual Texture has at least 3 layers.
Layer 4 Type	Dropdown	Default, Normal	The texture type of layer 4. This option only appears if the Virtual Texture has at least 4 layers.

Generated Code Example

The following example code represents one possible outcome of this node.

float4 SampleVirtualTexture(float2 uv, VTPropertyWithTextureType vtProperty, out float4 Layer0)
{
    VtInputParameters vtParams;
    vtParams.uv = uv;
    vtParams.lodOrOffset = 0.0f;
    vtParams.dx = 0.0f;
    vtParams.dy = 0.0f;
    vtParams.addressMode = VtAddressMode_Wrap;
    vtParams.filterMode = VtFilter_Anisotropic;
    vtParams.levelMode = VtLevel_Automatic;
    vtParams.uvMode = VtUvSpace_Regular;
    vtParams.sampleQuality = VtSampleQuality_High;
    #if defined(SHADER_STAGE_RAY_TRACING)
    if (vtParams.levelMode == VtLevel_Automatic || vtParams.levelMode == VtLevel_Bias)
    {
        vtParams.levelMode = VtLevel_Lod;
        vtParams.lodOrOffset = 0.0f;
    }
    #endif
    StackInfo info = PrepareVT(vtProperty.vtProperty, vtParams);
    Layer0 = SampleVTLayerWithTextureType(vtProperty, vtParams, info, 0);
    return GetResolveOutput(info);
}