[Mesa-dev] [PATCH] i965: Fix calculation of layers array length for isl_view

[Danylo Piliaiev]

Thank you Józef and Ilia for pointing this out!

I believe I have fully understood what's happening here and I'll send a 
final version of the fix soon.

On 9/7/18 7:47 PM, Józef Kucia wrote:
> On Fri, Sep 7, 2018 at 6:44 PM Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>> On Fri, Sep 7, 2018 at 12:35 PM, Józef Kucia <joseph.kucia at gmail.com> wrote:
>>> On Fri, Sep 7, 2018 at 4:42 PM Danylo Piliaiev
>>> <danylo.piliaiev at gmail.com> wrote:
>>>
>>>> @@ -1546,8 +1548,8 @@ update_image_surface(struct brw_context *brw,
>>>>               .format = format,
>>>>               .base_level = obj->MinLevel + u->Level,
>>>>               .levels = 1,
>>>> -            .base_array_layer = obj->MinLayer + u->_Layer,
>>>> -            .array_len = num_layers,
>>>> +            .base_array_layer = base_layer,
>>>> +            .array_len = num_layers - base_layer,
>>>>               .swizzle = ISL_SWIZZLE_IDENTITY,
>>>>               .usage = ISL_SURF_USAGE_STORAGE_BIT,
>>>>            };
>>> This sets the "array_len" to the number of layers remaining in the
>>> original texture. Shouldn't it take into account the number of layers
>>> in the GL texture view?
>> Errr, right. Here is the logic in st/mesa, which I believe is correct.
>> (But convoluted. Because there are so many bits to it.)
>>
>> https://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/state_tracker/st_atom_image.c#n101
> There is also view_num_layers in brw_update_texture_surface(). It
> could be adapted.