CODEWITHSUNDEEP
unity-game-engineshadertextures
Alex Scriba
Alex Scriba

Reputation: 105

How does one Render a texture directly to the Camera in Unity

In Unity, I have 2 images in the form of a texture that I am merging together (one overlaying the other). I do this in a Compute Shader and put the results on a RenderTexture. I want this RenderTexture to be everything that the output camera sees.

I have found articles saying to use a the ReplacementShader property of the camera, but I couldn't get that to properly work.

Currently I have simply put the RenderTexture onto a UIRawImage that covers the whole UI Canvas so that the entire camera is filled. This however has a lot of lag and is obviously a suboptimal solution.

So how does one output the Rendertexture or the compute Shader result directly onto the camera. Thanks.

Upvotes: 3

Views: 7074

Answers (1)

derHugo
derHugo

Reputation: 90683

You could probably use OnRenderImage

Event function that Unity calls after a Camera has finished rendering, that allows you to modify the Camera's final image.

and use Graphics.Blit

Copies source texture into destination render texture with a shader.

and do something like e.g.

// This script goes onto your according Camera
public class RenderReplacement : MonoBehaviour
{
    public RenderTexture replacement;

    void OnRenderImage(RenderTexture src, RenderTexture dest)
    {
        // To overwrite the entire screen
        Graphics.Blit(replacement, null);

        // Or to overwrite only what this specific Camera renders
        //Graphics.Blit(replacement, dest);
    }
}

Where

dest
The destination RenderTexture. Set this to null to blit directly to screen. See description for more information.

Note as mentioned in the API the OnRenderImage is called after this Camera already finished rendering. So in order to make this more efficient - since we basically throw away that render - simply make sure that camera basically isn't rendering anything by disabling all Layers and e.g. let it only render a single color background

Upvotes: 6

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