[Buildroot] [PATCH 1/5] package/mesa3d: allow to enable OpenGL texture float support

[Romain Naour]

Hi Bernd, All

Le 28/03/2017 à 19:49, Bernd Kuhls a écrit :
> Am Sun, 26 Mar 2017 18:28:49 +0200 schrieb Romain Naour:
> 
>> OpenGL version string: 2.1 Mesa 17.0.2
>> It turn out that texture float support was missing...
>> OpenGL version string: 3.0 Mesa 17.0.2
> [...]
>> +ifeq ($(BR2_PACKAGE_MESA3D_OPENGL_TEXTURE_FLOAT),y)
>> +MESA3D_CONF_OPTS += --enable-texture-float
>> +MESA3D_LICENSE_FILES += docs/patents.txt
>> +else
>> +MESA3D_CONF_OPTS += --disable-texture-float
>> +endif
> 
> Hi,
> 
> wondering why Kodi already prints
> 
> NOTICE: GL_VERSION = 3.0 Mesa 17.0.2
> 
> during startup on my system without your patch and 
> BR2_PACKAGE_MESA3D_DRI_DRIVER_I965=y I investigated its changes and 
> compiled this defconfig (snipped non-mesa3d options):
> 
> BR2_PACKAGE_MESA3D=y
> BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_NOUVEAU=y
> BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_R600=y
> BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_SVGA=y
> BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_SWRAST=y
> BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_VIRGL=y
> BR2_PACKAGE_MESA3D_DRI_DRIVER_SWRAST=y
> BR2_PACKAGE_MESA3D_DRI_DRIVER_I915=y
> BR2_PACKAGE_MESA3D_DRI_DRIVER_I965=y
> BR2_PACKAGE_MESA3D_DRI_DRIVER_NOUVEAU=y
> BR2_PACKAGE_MESA3D_DRI_DRIVER_RADEON=y
> BR2_PACKAGE_MESA3D_OSMESA=y
> BR2_PACKAGE_MESA3D_OPENGL_ES=y
> BR2_PACKAGE_XORG7=y
> 
> with
> BR2_PACKAGE_MESA3D_OPENGL_TEXTURE_FLOAT=y
> 
> and without your patch.
> 
> The directory output/target/usr/lib/dri/ contains these files, I added a 
> note when the filesize changed due to --enable-texture-float:
> 
> i915_dri.so
> i965_dri.so
> kms_swrast_dri.so	(changed)
> nouveau_dri.so		(changed, same as kms_swrast_dri.so)
> nouveau_vieux_dri.so
> r600_dri.so		(changed, same as kms_swrast_dri.so)
> radeon_dri.so
> swrast_dri.so		(changed, same as kms_swrast_dri.so)
> virtio_gpu_dri.so	(changed, same as kms_swrast_dri.so)
> vmwgfx_dri.so		(changed, same as kms_swrast_dri.so)

Good catch :)

> 
> libGL.so/libEGL.so/libGLES*.so stayed unchanged.
> 
> Afaics the reason why the Intel drivers are unaffected could be this line 
> of code where texture float support is always enabled:
> 
> https://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/drivers/dri/i965/
> intel_extensions.c?h=17.0#n83
> 
> Other parts of the mesa3d contain #ifdef, like this:
> https://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/main/extensions.c?
> h=17.0#n134

Indeed, I saw the ifdef TEXTURE_FLOAT_ENABLED in mesa/main/extensions.c while
checking what --enable-texture-float was doing, but I didn't noticed that it was
always enabled for Intel devices...

It's seems a bug in mesa/drivers/dri/i965/intel_extensions.c which is not
affected by this option...

> 
> I am not familiar with the internal structures of mesa3d beyond my 
> observations, maybe you should add a note to Config.in that your 
> configure option does not affect all drivers.

Me too, I spent several hours searching why OpenGL was in compat mode with the
system produced by Buildroot... I tested the same target with Fedora and noticed
that OpenGL 3.3 was enabled.

Ok, I'll add a note about this.

Do you have any comment on the following patches of this series ?

Best regards,
Romain

> 
> Regards, Bernd
> 
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