Upcoming Qt switch to OpenGL ES on arm64

[Andy Simpkins]

On 24/11/18 14:14, bret curtis wrote:
>>> But even here in this place I have seen *a lot* of "cheap" arm64 boards. Yes,
>>> the RPI3[+] is ubiquitous. And having to render Open GL stuff by CPU is
>>> precisely not the fastest thing around.
>>
>> <paraphrase> "I have a Raspberry Pi (or similar mobile class system that
>> has migrated / is migrating away from armel to arm64) and this has
>> forced a move from 'mobile' OpenGLES to 'Desktop' OpenGL.  The result of
>> which is that because that platform (and those like it) do not have
>> hardware acceleration for OpenGL but DO for OpenGLES you think we should
>> change the whole architecture for your use case." </paraphrase>
>>
> 
> This is a very wrong assumption, the OpenGL on a RPi (all of them) is
> hardware accelerated via the VC4 mesa driver by Eric Anholt which is
> shipped, by default, on by Raspbian. It supports up to OpenGL 2.1 and
> if you plan on having hardware accelerated X11 or Wayland, you need
> the VC4 driver. You'll need "Desktop" OpenGL otherwise nothing will
> work on a RPi system, which as of 2015 has over 5 million units
> shipped. This is not an insignificant user base.
> 
> IMHO, the decision to switch away from 'Desktop' OpenGL to GLES was
> the wrong decision and should be reversed until a solution is found to
> support both.
> 
> Cheers,
> Bret
> 

Apologies for using the RaspberryPi as my example of a 'mobile' class SoC.

IIRC the Pi was being used as the primary argument for switching away
from OpenGL to OpenGLES as this is selling in large volumes.  If the Pi
already supports OpenGL then the argument to move solely to OpenGLES is
reduced somewhat.

I will try OpenGL on a RPi this week (I normally run RPi headless so no
desktop installed).

/Andy