[Mesa-dev] [PATCH 2/4] st/mesa: set the new pipe_surface::alpha_one field for RGB surfaces

[Brian Paul]

On 06/23/2016 08:14 PM, Ilia Mirkin wrote:
> Isn't this true for any-non-alpha-having format? I.e. _BaseFormat !=
> GL_RGBA && _BaseFormat != GL_ALPHA && _BaseFormat !=
> GL_LUMINANCE_ALPHA && _BaseFormat != GL_INTENSITY? (Not sure about
> that last one tbh.)

One would also have to check for GL_DEPTH, GL_STENCIL, etc.

I could do this:

surf_tmpl.alpha_one = (strb->Base._BaseFormat == GL_RGB ||
                        strb->Base._BaseFormat == GL_LUMINANCE);

OK?

-Brian


>
> On Thu, Jun 23, 2016 at 10:07 PM, Brian Paul <brianp at vmware.com> wrote:
>> This indicates the alpha channel of the surface should always be one.
>> Drivers can use this to adjust blending terms when needed.
>> ---
>>   src/mesa/state_tracker/st_cb_fbo.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
>> index 9801b1f..012d7d7 100644
>> --- a/src/mesa/state_tracker/st_cb_fbo.c
>> +++ b/src/mesa/state_tracker/st_cb_fbo.c
>> @@ -216,6 +216,8 @@ st_renderbuffer_alloc_storage(struct gl_context * ctx,
>>         return FALSE;
>>
>>      u_surface_default_template(&surf_tmpl, strb->texture);
>> +   surf_tmpl.alpha_one = (strb->Base._BaseFormat == GL_RGB);
>> +
>>      strb->surface = pipe->create_surface(pipe,
>>                                           strb->texture,
>>                                           &surf_tmpl);
>> @@ -463,6 +465,7 @@ st_update_renderbuffer_surface(struct st_context *st,
>>         /* create a new pipe_surface */
>>         struct pipe_surface surf_tmpl;
>>         memset(&surf_tmpl, 0, sizeof(surf_tmpl));
>> +      surf_tmpl.alpha_one = (strb->Base._BaseFormat == GL_RGB);
>>         surf_tmpl.format = format;
>>         surf_tmpl.u.tex.level = level;
>>         surf_tmpl.u.tex.first_layer = first_layer;
>> --
>> 1.9.1
>>
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