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Create a temporary texture for a single frame in URP

Create a temporary texture in a render pass, also known as an internal resource.
Read time 3 minutesLast updated a month ago
To create a temporary texture in the render graph system, use the 
CreateTexture
method of the render graph instance.
When you create a texture inside a render pass, the render graph system handles the creation and disposal of the texture. This process means the texture might not exist in the next frame, and other cameras might not be able to use it. To make sure a texture is available across frames and cameras, refer to Use a texture in multiple render passes instead.
When the render graph system optimizes the render pipeline, it might not create a texture if the final frame doesn't use the texture, to reduce the memory and bandwidth the render passes use.

Create a temporary texture

In the 
RecordRenderGraph
method of your 
ScriptableRenderPass
class, follow these steps:
  1. Create a 
    TextureDesc
     object with the texture properties you need.
  2. Use the 
    CreateTexture
     method of the render graph instance to create a texture and return a texture handle.
For example, the following creates a texture the same size as the screen.
UniversalResourceData resourceData = frameData.Get<UniversalResourceData>();TextureDesc textureDesc = resourceData.activeColorTexture.GetDescriptor(renderGraph);TextureHandle textureHandle = renderGraph.CreateTexture(textureDesc);
Note
Avoid using 
UniversalRenderer.CreateRenderGraphTexture
, because it can introduce subtle bugs.
The render graph system manages the lifetime of textures you create with 
CreateTexture
, so you don't need to manually dispose of the memory they use when you're finished with them.

Inspect how URP handles load actions on a texture

You can use the Render Graph Viewer window to inspect how URP handles load actions on textures. This is useful to debug your results and confirm whether Unity clears, preserves, or discards a texture.
Note
The 
clear
parameter and the 
AccessFlags
value affect how URP sets the load action for a texture. This can impact rendering results:
  • If 
    clear
    is 
    true
    and you use 
    AccessFlags.WriteAll
    , the load action is 
    DontCare
    , not 
    Clear
    . This is because Unity assumes you're overwriting the entire texture, so it skips clearing the texture to optimize performance.
  • If 
    clear
    is 
    false
    and you use 
    AccessFlags.Write
    , the load action is 
    Clear
    . This is because Unity clears the texture automatically to avoid rendering artifacts if you only write part of the texture. To skip Unity clearing the texture, use 
    AccessFlags.WriteAll
    to explicitly tell Unity you're writing the full texture.

Example

The following Scriptable Renderer Feature contains an example render pass that creates a texture and clears it to yellow. For more information about adding the render pass to the render pipeline, refer to Inject a pass using a Scriptable Renderer Feature.
Use the Frame Debugger to check the texture the render pass adds.
using UnityEngine;using UnityEngine.Rendering.Universal;using UnityEngine.Rendering.RenderGraphModule;using UnityEngine.Rendering;public class CreateYellowTextureFeature : ScriptableRendererFeature{    CreateYellowTexture customPass;    public override void Create()    {        customPass = new CreateYellowTexture();        customPass.renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing;    }    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)    {        renderer.EnqueuePass(customPass);    }    class CreateYellowTexture : ScriptableRenderPass    {        class PassData        {            public TextureHandle cameraColorTexture;        }        public override void RecordRenderGraph(RenderGraph renderGraph, ContextContainer frameData)        {            using (var builder = renderGraph.AddRasterRenderPass<PassData>("Create yellow texture", out var passData))            {                // Get the frame data                UniversalResourceData resourceData = frameData.Get<UniversalResourceData>();                // Create texture properties that match the screen size                TextureDesc textureDesc = resourceData.activeColorTexture.GetDescriptor(renderGraph);                textureDesc.msaaSamples = MSAASamples.None;                // Create a temporary texture                TextureHandle texture = renderGraph.CreateTexture(textureDesc);                // Set the texture as the render target                builder.SetRenderAttachment(texture, 0, AccessFlags.Write);                    // Make sure the render graph system keeps the render pass, even if it's not used in the final frame.                // Don't use this in production code, because it prevents the render graph system from removing the render pass if it's not needed.                builder.AllowPassCulling(false);                builder.SetRenderFunc(static (PassData data, RasterGraphContext context) => ExecutePass(data, context));            }        }        static void ExecutePass(PassData data, RasterGraphContext context)        {                      // Clear the render target to yellow            context.cmd.ClearRenderTarget(true, true, Color.yellow);                    }    }}

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