WebGLRenderTarget: .clone() does not clone framebuffer/texture data.

Description of the problem

When cloning an equirectangular CubeTexture the result is a black texture. The same operation does work with a CubeTextureLoader loaded texture (with 6 images).

No map after clone()

• jsfiddle clone (latest release branch)
• jsfiddle clone (dev branch)

Three.js version

• Dev
• r117

Browser

• All of them
• Chrome
• Firefox
• Internet Explorer

OS

• All of them
• Windows
• macOS
• Linux
• Android
• iOS

Hardware Requirements (graphics card, VR Device, …)

Resolved

When using refraction for an equirectangular texture with EquirectangularRefractionMapping, using it as a background does not work, an the mapping has wrong seams. For CubeTextureLoader with CubeRefractionMapping both of that works (see cubemap refraction).

wrong background rendering & seam

• jsfiddle refraction (dev branch)

[Mugen87]

The clone() methods in three.js turned out to be problematic in various classes. They work well with math primitives but cloning more complex objects is problematic since it is not always possible to replicate the “correct” object state. This is especially true for render targets. After reconsidering this issue, it’s just not feasible to copy framebuffer data for cloned render targets. So WebGLRenderTarget.clone() just creates a new render target with the same configuration but not with copied data.

[JohannesDeml]

I guess I would prefer to report a warning in this case.

Sounds like a good solution. I agree, that it is kind of strange that it works.

For me the only valid feature request of this issue is the ability to clone render targets. Yes, I’m with you on that. Thanks for pointing me in the right direction with the mapping type. The docs are missing that description, I will add that today 😃