[BUG] the backbuffer format is always SRGB

[zhaijialong]

Description

The emulator doesn't say it support EGL_KHR_gl_colorspace, but always create a r8g8b8a8_unorm_srgb format backbuffer in the underlying implementation.

It should use a linear format backbuffer as default if doesn't support EGL_KHR_gl_colorspace.

The better way is to expose the EGL_KHR_gl_colorspace egl extension, and let user to config it to determine whether to use a srgb backbuffer

EGLint eglSurfaceAttributes[3]
eglSurfaceAttributes[0] = EGL_GL_COLORSPACE_KHR;
eglSurfaceAttributes[1] = EGL_GL_COLORSPACE_SRGB_KHR;
eglSurfaceAttributes[2] = EGL_NONE;
egl::CreateWindowSurface(..., eglSurfaceAttributes)

Repro steps

Environment

• SDK version: 18.2@5236813
• Operating System/Device: Windows 10/GTX 1060

Additional Info

And the emulator says it support EGL 1.5, EGL_KHR_gl_colorspace should be in EGL 1.5. But if I try

EGLint eglSurfaceAttributes[3]
eglSurfaceAttributes[0] = EGL_GL_COLORSPACE;
eglSurfaceAttributes[1] = EGL_GL_COLORSPACE_SRGB;
eglSurfaceAttributes[2] = EGL_NONE;
egl::CreateWindowSurface(..., eglSurfaceAttributes)

the egl::CreateWindowSurface will hang my process.

[graptis]

Hi @zhaijialong,
Thanks for the report.
I have forwarded this to the engineers responsible for PVRVFrame, but since this is a matter of Tools and not the actual codebase of the SDK, support will arguably be better in https://forums.imgtec.com/ which are for this purpose only. I would suggest opening an issue there (as well?).
(We can still keep this issue open, but probably feedback will be sparse).

[zhaijialong]

https://forums.imgtec.com/t/issue-bug-the-backbuffer-format-is-always-srgb/2954