[Mesa-dev] [PATCH 0/2] Disable the EGL state tracker for Linux/DRI builds

[Marek Olšák]

On Wed, Nov 5, 2014 at 9:02 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On 05.11.2014 07:42, Marek Olšák wrote:
>>
>> Hi everybody,
>>
>> I'm about to address this long-standing issue: The EGL state tracker is
>> redundant. It duplicates what st/dri does and it also duplicates what
>> the common loader egl_dri2 does, which is used by all classic drivers
>> and even works better with gallium drivers.
>>
>> Let's compare EGL extensions for both backends:
>>
>> st/egl:
>> EGL version string: 1.4 (Gallium)
>> EGL client APIs: OpenGL OpenGL_ES OpenGL_ES2 OpenVG
>> EGL extensions string:
>>      EGL_WL_bind_wayland_display EGL_KHR_image_base EGL_KHR_image_pixmap
>>      EGL_KHR_image EGL_KHR_reusable_sync EGL_KHR_fence_sync
>>      EGL_KHR_surfaceless_context EGL_NOK_swap_region
>>      EGL_NV_post_sub_buffer
>>
>> egl_dri2:
>> EGL version string: 1.4 (DRI2)
>> EGL client APIs: OpenGL OpenGL_ES OpenGL_ES2 OpenGL_ES3
>> EGL extensions string:
>>      EGL_MESA_drm_image EGL_MESA_configless_context EGL_KHR_image_base
>>      EGL_KHR_image_pixmap EGL_KHR_image EGL_KHR_gl_texture_2D_image
>>      EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image
>>      EGL_KHR_surfaceless_context EGL_KHR_create_context
>>      EGL_NOK_swap_region EGL_NOK_texture_from_pixmap
>>      EGL_CHROMIUM_sync_control EGL_EXT_image_dma_buf_import
>>      EGL_NV_post_sub_buffer
>>
>> egl_dri2 also supports MSAA on the window framebuffer (through st/dri).
>> It's really obvious which one is better.
>
>
> No argument there.
>
>
>> - OpenVG - It has never taken off. If people want this on Linux, it should
>> use egl_dri2 and st/dri, like OpenGL does.
>
>
> The problem is doing so would probably be a lot of work, so this creates a
> huge barrier for somebody who wants to play with OpenVG.
>
> How about keeping egl_gallium but only using it if EGL_DRIVER=egl_gallium is
> specified explicitly? (I assume automatically using egl_gallium for OpenVG
> isn't possible due to the way EGL works)

Another alternative is to use a library which implements OpenVG on top
of OpenGL. For example:
- http://sourceforge.net/projects/shivavg/
- https://github.com/micahpearlman/MonkVG

Marek