Version: 2021.3
LanguageEnglish
  • C#
Virtual Texturing is experimental and not ready for production use. The feature and documentation might be changed or removed in the future.

Streaming.RequestRegion

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Declaration

public static void RequestRegion(Material mat, int stackNameId, Rect r, int mipMap, int numMips);

Parameters

mat The Material that contains the Virtual Texture Stack. The Virtual Texture Stacks contained in a Material are declared in the Material's Shader.
stackNameId The unique identifier for the name of the Virtual Texture Stack, as declared in the Shader. To find the identifier for a given Shader property name, use Shader.PropertyToID.
r The rectangle in 0-1 UV space to make resident. Anything outside the [ 0...1 [ x [ 0...1 [ rectangle will be silently ignored.
mipMap The mip level to make resident. Mips are numbered from 0 (= full resolution) to n (= lowest resolution) where n is the mipmap level what is a single tile in size. Requesting invalid mips is silently ignored.
numMips The number of mip levels starting from 'mipMap' to make resident. Requesting invalid mips is silently ignored.

Description

Make a rectangle in UV space resident for a given Virtual Texture Stack.

The system will do it’s best to make this rectangle resident at the requested resolution as fast as possible but due to time and memory constraints this data may take a while to become resident or even never become resident. This function should be called regularly (preferably every frame) to indicate the continued interest in this data. When this function is no longer called the requested area may be evicted from memory or only be available at a lower resolution. See Streaming.RequestRegion for an example using this function.

using System;
using UnityEngine;

/** * Request the 256x256 pixel mipmap level of a given Virtual Texture Stack. */ public class GetStackSizesample : MonoBehaviour { public Material targetMaterial; public string stackName;

void Update() { int stackPropertyId = Shader.PropertyToID(stackName);

// Get size in pixels of the stack. int width, height; UnityEngine.Rendering.VirtualTexturing.Streaming.GetTextureStackSize(targetMaterial, stackPropertyId, out width, out height);

// Calculate index of the 256x256 mip (or mip 0 if the texture is smaller than 256x256) int textureMip = (int)Math.Max(Mathf.Log(width, 2f), Mathf.Log(height, 2f)); const int baseMip = 8; int mipLevel = Math.Max(textureMip - baseMip, 0);

// Request this mip to be made resident UnityEngine.Rendering.VirtualTexturing.Streaming.RequestRegion(targetMaterial, stackPropertyId, new Rect(0.0f, 0.0f, 1.0f, 1.0f), mipLevel, UnityEngine.Rendering.VirtualTexturing.System.AllMips); } }