Currently the "gles2" USE flag is disabled, because Ogre-1.12.x unconditionally includes hlsl2glsl.h, which causes the build to fail. It also tries to utilize glsl-optimizer, which is also not available. So for being able to have the OpenGL ES2/3 Render System back, we need ebuilds for * https://github.com/aras-p/hlsl2glslfork and * https://github.com/aras-p/glsl-optimizer Note: A PR is on its way, but I have to wait for https://github.com/gentoo/gentoo/pull/17619 to be merged, as it is based on that. I have already tested the SampleBrowser with "OpenGL ES2/3 Render System" and everything looks solid" Reproducible: Always
As Ross C. pointed out, hlsl2glsl and glsl-optimizer are no longer hard wired into GLES2-enabled builds. This was the case until v1.12.8, and now that we have ebuilds for these tools, upstream fixed it. The PR has been updated to no longer add these two tools as new packages, as they are strictly back to being absolutely optional. A separate bug and PR might be opened to add HLSL Shader support and GLSL Shader Optimization.
Looks like the situation has resolved and unless hlsl2glslfork gets added to ::gentoo the gles2 useflag is not coming back. If still interested/needed, please discuss on #gentoo-games or file a new package bug for it.