Graphics.Blit

Parameters

Description

Uses a shader to copy the pixel data from a texture into a render target.

This method copies pixel data from a texture on the GPU to a render texture or graphics texture on the GPU. This is one of the fastest ways to copy a texture.

When you use Graphics.Blit, Unity does the following:

1. Sets the active render target to the dest texture. (See RenderTexture.active and GraphicsTexture.active.)
2. Passes source to the mat material as the _MainTex property.
3. Uses the material's shader to draw a full-screen surface from the source texture to the dest texture.

If you provide a mat material that doesn't have a _MainTex property, Blit doesn't use source. If you provide a GraphicsTexture as dest, it must have GraphicsTextureDescriptorFlags.RenderTarget enabled in its GraphicsTextureDescriptor.flags.

You can use Graphics.Blit to create post-processing effects, by setting mat to a material with a custom shader.

Blit changes RenderTexture.active and GraphicsTexture.active. Store the active render target before you use Blit if you need to use it afterwards.

Avoid setting source and dest to the same texture, as this may cause undefined behaviour. Use Custom Render Textures with double buffering instead, or use two render textures and alternate between them to implement double buffering manually.

In linear color space, set GL.sRGBWrite before using Blit, to make sure the sRGB-to-linear color conversion is what you expect.

To blit to the screen in the Built-in Render Pipeline, follow these steps:

1. Set dest to null. Unity now uses Camera.main.targetTexture as the destination texture.
2. Set the Camera.targetTexture property of Camera.main to null.

To blit to the screen in the Universal Render Pipeline (URP) or the High Definition Render Pipeline (HDRP), you must call Graphics.Blit or CommandBuffer.Blit inside a method that you call from the RenderPipelineManager.endContextRendering callback.

If you want to use a depth or stencil buffer that is part of the source (Render)texture, or blit to a subregion of a texture, you have to manually write an equivalent of the Graphics.Blit function - i.e. Graphics.SetRenderTarget with destination color buffer and source depth buffer, setup orthographic projection (GL.LoadOrtho), setup material pass (Material.SetPass) and draw a quad (GL.Begin).

Additional resources: Graphics.BlitMultiTap, Post-processing effects.

using UnityEngine;

public class Example : MonoBehaviour
{ // Copies aTexture to rTex and displays it in all cameras.

    Texture aTexture;
    RenderTexture rTex;

    void Start()
    {
        if (!aTexture || !rTex)
        {
            Debug.LogError("A texture or a render texture are missing, assign them.");
        }
    }

    void Update()
    {
        Graphics.Blit(aTexture, rTex);
    }
}