WebGLRenderer: Difference between Scene.background and setClearColor()

Using Scene.background and WebGLRenderer.setClearColor() produces the same output in the following demos:

Scene.background: https://jsfiddle.net/xkf3o8uw/5/ setClearColor(): https://jsfiddle.net/xkf3o8uw/4/

However, when setting autoClear to false, the behavior is different:

Scene.background: https://jsfiddle.net/0o38d67m/ setClearColor(): https://jsfiddle.net/xkf3o8uw/2/

Scene.background still works because of this line in Scene.background:

https://github.com/mrdoob/three.js/blob/a4f742c7d7b61f3efae147235efb0b5bc73e6e03/src/renderers/webgl/WebGLBackground.js#L52

What is the reason for this discrepancy? Does it just mean Scene.background used with a color should be decoupled of autoClear settings?

[WestLangley]

Do you mind mentioning them^^?

Sure.

renderer.setClearColor( 0xff0000, 0.5 ); // the behavior is as-expected

• supports alpha
• ignores viewport
• ignores outputEncoding
• ignores tonemapping
• honors scissor

scene.background = new THREE.Color( 0xff0000 ); // it currently behaves similar to clear color

• does not support alpha
• ignores viewport
• ignores outputEncoding
• ignores tonemapping
• honors scissor

scene.background = new THREE.DataTexture( new Uint8Array( [ 255, 0, 0 ] ), 1, 1, THREE.RGBFormat );

• does not support alpha
• honors viewport
• honors outputEncoding
• honors tonemapping
• honors scissor
• honors encoding

I think that is all correct…

And for consistency, the scene background color should be assumed to be in linear colorspace. Currently it is an unusual special case.

[wmcmurray]

+1 That forceClear = true got me real confused this morning, I didn’t expect Scene.background to still clear the color even if autoClear === false 😕 ! For that reason, I ended up not using Scene.background at all.