Change renderer.gammaInput/renderer.gammaOutput on the fly?

[qornflex]

Hi guys,

Is there a way to change these parameters in real-time?

It seems the shader programs don't take it in consideration... even if I tell my materials to be updated (needsUpdate=true) after the change.

Or maybe there is a good reason that explains the WebGLRenderer needs to be disposed and instanciated again?

Many thanks.

Q.

[WestLangley]

Can you please explain your use case?

I understand that one use case would be to render to a texture with linear output (for further processing) and then render to the screen with gamma output.

You can avoid setting renderer.gammaInput and set texture.encoding instead. (See http://threejs.org/docs/#api/constants/Textures.) You will have to set material.needsUpdate if the encoding is changed after the first render.

Currently, I am not sure if output encoding on a per-material basis has been fully implemented.

This entire issue regarding encoding and extensions probably needs to be revisited.

/ping @bhouston

three.js r.85

[bhouston]

gammaOutput, gammaInput are legacy. You can set per-texture and per-render target encodings for read/write. I'd do more research there and see if that can meet your needs.

[bhouston]

Just to be clear, use texture.encoding for reading and writing using various different encodings.

[WestLangley]

@bhouston I see that one can specify an encoding for a texture and an encoding for a render target.

However, in the case of rendering to the screen, I think the encoding is always LinearEncoding, unless gammaOutput = true, in which case it is GammaEncoding.

To the best of my knowledge, there are no other options. Am I missing something?

Do we need to deprecate renderer.gammaOutput and add renderer.outputEncoding, and declare outputEncoding applies only when rendering to the screen?

[qornflex]

Hi guys, thanks for your replies.
@WestLangley: I'm building a previewer of MAX scenes for a client and I would like to let the user choose the type of Color Space (Gamma or Linear).

It would be very nice to have something similar to Unity or Unreal.... for example:

renderer.colorSpace = THREE.LinearEncoding;
or
renderer.colorSpace = THREE.GammaEncoding;

I could work with deprecated gammaInput/Output but on-the-fly changes are not taken in consideration. The WebGLRenderer must be disposed and instantiated again ...

I looked at the source and it seems the Shader Programs do not tell the textures the encoding has changed.

[bhouston]

Do we need to deprecate renderer.gammaOutput and add renderer.outputEncoding, and declare outputEncoding applies only when rendering to the screen?

I agree with the above (BTW there is always an outputEncoding declared, it is just usually sourced from looking at the renderTarget.encoding or failing that renderer.outputGamma -- we just need it ot use the renderer.encoding instead of renderer.outputGamma.) That end result you propose is what I intended but it does break every single example that currently uses gammaInput and gammaOutput, but it is the right thing to do for correctness and code simplification.

[bhouston]

We just need to modify this function call to get the renderer.outputEncoding:

three.js/src/renderers/webgl/WebGLPrograms.js

Line 136 in 7f55016

outputEncoding: getTextureEncodingFromMap( ( ! currentRenderTarget ) ? null : currentRenderTarget.texture, renderer.gammaOutput ),

[WestLangley]

Great! We are all on the same page. :)

@ortofon For now you can hack WebGLPrograms.getProgramCode() and make this change:

array.push( renderer.gammaOutput ); // add this line

return array.join();

Setting material.needsUpdate will then do what you expect.

We can figure out the best way to deprecate renderer.gammaInput and renderer.gammaOutput.

[qornflex]

Thank you very much guys!