PMREMGenerator flips the X axis when receiving a non CubeTexture

[jsantell]

Description of the problem

When using a texture from WebGLRenderTargetCube (e.g. EquirectangularToCubeGenerator) with PMREMGenerator, the generated environment map does not match the environment, and is flipped on the X axis, unlike when using a CubeTexture.

This can be recreated in the EXR example and:

scene.background = cubemapGenerator.renderTarget;
//cubemapGenerator.dispose();

Three.js version

• Dev
• r98
• ...

Browser

• All of them
• Chrome
• Firefox
• Internet Explorer

OS

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

Hardware Requirements (graphics card, VR Device, ...)

[WestLangley]

Yes. I believe the following statements are true:

In webgl_materials_envmaps_hdr, reflections are correct, but the PMREM Cube_UV map tiles are mirrored.

in webgl_materials_envmaps_exr, reflections are mirrored, but the PMREM Cube_UV map tiles are correct.