No pbuffer configurations available on Mir on X even if available in X

[Nick Dedekind]

Available configurations via eglinfo

X11 platform:
EGL API version: 1.4
EGL vendor string: Mesa Project
EGL version string: 1.4 (DRI2)
EGL client APIs: OpenGL OpenGL_ES OpenGL_ES2 OpenGL_ES3
EGL extensions string:
    EGL_CHROMIUM_sync_control EGL_EXT_create_context_robustness
    EGL_EXT_image_dma_buf_import EGL_KHR_create_context
    EGL_KHR_fence_sync EGL_KHR_get_all_proc_addresses
    EGL_KHR_gl_renderbuffer_image EGL_KHR_gl_texture_2D_image
    EGL_KHR_gl_texture_cubemap_image EGL_KHR_image EGL_KHR_image_base
    EGL_KHR_image_pixmap EGL_KHR_surfaceless_context EGL_KHR_wait_sync
    EGL_MESA_configless_context EGL_MESA_drm_image
    EGL_MESA_image_dma_buf_export EGL_NOK_swap_region
    EGL_NOK_texture_from_pixmap EGL_NV_post_sub_buffer
    EGL_WL_bind_wayland_display
Configurations:
     bf lv colorbuffer dp st ms vis cav bi renderable supported
  id sz l r g b a th cl ns b id eat nd gl es es2 vg surfaces
---------------------------------------------------------------------
0x0e 32 0 8 8 8 8 0 0 0 0 0x20TC a y y y win,pb,pix
0x12 32 0 8 8 8 8 24 8 0 0 0x20TC a y y y win,pb,pix
0x15 24 0 8 8 8 0 0 0 0 0 0x20TC y y y y win,pb,pix
0x19 24 0 8 8 8 0 24 8 0 0 0x20TC y y y y win,pb,pix
0x2e 32 0 8 8 8 8 0 0 4 1 0x20TC a y y y win,pb
0x30 32 0 8 8 8 8 24 8 4 1 0x20TC a y y y win,pb
0x31 24 0 8 8 8 0 0 0 4 1 0x20TC y y y y win,pb
0x33 24 0 8 8 8 0 24 8 4 1 0x20TC y y y y win,pb
0x42 32 0 8 8 8 8 0 0 0 0 0x21DC a y y y win,pb,pix
0x46 32 0 8 8 8 8 24 8 0 0 0x21DC a y y y win,pb,pix
0x49 24 0 8 8 8 0 0 0 0 0 0x21DC y y y y win,pb,pix
0x4d 24 0 8 8 8 0 24 8 0 0 0x21DC y y y y win,pb,pix
0x62 32 0 8 8 8 8 0 0 4 1 0x21DC a y y y win,pb
0x64 32 0 8 8 8 8 24 8 4 1 0x21DC a y y y win,pb
0x65 24 0 8 8 8 0 0 0 4 1 0x21DC y y y y win,pb
0x67 24 0 8 8 8 0 24 8 4 1 0x21DC y y y y win,pb

Mir platform:
EGL API version: 1.4
EGL vendor string: Mesa Project
EGL version string: 1.4 (DRI2)
EGL client APIs: OpenGL OpenGL_ES OpenGL_ES2 OpenGL_ES3
EGL extensions string:
    EGL_EXT_buffer_age EGL_EXT_image_dma_buf_import
    EGL_KHR_create_context EGL_KHR_get_all_proc_addresses
    EGL_KHR_gl_renderbuffer_image EGL_KHR_gl_texture_2D_image
    EGL_KHR_gl_texture_cubemap_image EGL_KHR_image EGL_KHR_image_base
    EGL_KHR_image_pixmap EGL_KHR_surfaceless_context
    EGL_MESA_configless_context EGL_MESA_drm_image
    EGL_MESA_image_dma_buf_export
Configurations:
     bf lv colorbuffer dp st ms vis cav bi renderable supported
  id sz l r g b a th cl ns b id eat nd gl es es2 vg surfaces
---------------------------------------------------------------------
0x07 32 0 8 8 8 8 0 0 0 0 0x00-- y y y win
0x09 32 0 8 8 8 8 24 8 0 0 0x00-- y y y win
0x17 32 0 8 8 8 8 0 0 4 1 0x00-- y y y win
0x18 32 0 8 8 8 8 24 8 4 1 0x00-- y y y win

[Daniel van Vugt (vanvugt)]

Related: bug 1618815

[Chris Halse Rogers (raof)]

There's no reason to provide pbuffers (and a number of platforms, notably Wayland, do not). FBOs do the same thing, but better.