| source | The source texture or RenderTargetIdentifier. |
| dest | The destination RenderTargetIdentifier. |
| mat | The material to use. If you don't provide mat, Unity uses a default material. |
| pass | If the value is -1, Unity draws all the passes in mat. Otherwise, Unity draws only the pass you set pass to. The default value is -1. |
| scale | The scale to apply. |
| offset | The offset to apply. |
| sourceDepthSlice | The element in the source texture to copy from, for example the texture in a texture array. You can't use sourceDepthSlice to specify a face in a Cubemap. |
| destDepthSlice | The element in the destination texture to copy from, for example the texture in a texture array. You can't use destDepthSlice to specify a face in a Cubemap. |
Adds a command to use a shader to copy the pixel data from a texture into a render texture.
This method adds a command to copy pixel data from a texture on the GPU to a render texture on the GPU. This is one of the fastest ways to copy a texture.
When you use Graphics.Blit, Unity does the following:
Sets the active render texture to the dest texture.
Passes source to the mat material as the _MainTex property.
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.
You can use Graphics.Blit to create post-processing effects, by setting mat to a material with a custom shader.Blit changes RenderTexture.active. Store the active render texture before you use Blit if you need to use it afterwards.
Avoid setting source and dest to the same render 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:
Set dest to null. Unity now uses Camera.main.targetTexture as the destination texture.
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).
Often the previous content of the Blit dest does not need to be preserved. In this case, it is recommended to activate the dest render target explicitly with the appropriate load and store actions using SetRenderTarget. The Blit dest should then be set to BuiltinRenderTextureType.CurrentActive.
Additional resources: Graphics.BlitMultiTap, Post-processing effects.