[PATCH v2 2/4] wined3d: Add push constants to wined3d_pipeline_layout_key_vk.

[Jan Sikorski]

> On 20 Aug 2021, at 09:52, Henri Verbeet <hverbeet at gmail.com> wrote:
> 
> On Tue, 17 Aug 2021 at 16:02, Jan Sikorski <jsikorski at codeweavers.com> wrote:
>> @@ -1746,7 +1746,10 @@ static int wined3d_pipeline_layout_vk_compare(const void *key, const struct wine
>> 
>>     if (a->binding_count != b->binding_count)
>>         return a->binding_count - b->binding_count;
>> -    return memcmp(a->bindings, b->bindings, a->binding_count * sizeof(*a->bindings));
>> +    if (a->push_constant_count != b->push_constant_count)
>> +        return a->push_constant_count - b->push_constant_count;
>> +    return memcmp(a->bindings, b->bindings, a->binding_count * sizeof(*a->bindings)) ||
>> +            memcmp(a->push_constants, b->push_constants, a->push_constant_count * sizeof(*a->push_constants));
>> }
>> 
> That doesn't do the right thing, the compare needs to be ordered.

I wonder how it didn’t break everything. Somehow I imagined that || returns its first nonzero input..

>>     memcpy(layout->key.bindings, key.bindings, sizeof(*layout->key.bindings) * key.binding_count);
>>     layout->key.binding_count = key.binding_count;
>> +    layout->key.push_constants = (VkPushConstantRange *)(layout->key.bindings + key.binding_count);
> 
> By convention, we'd write that as "layout->key.push_constants =
> (VkPushConstantRange *)&layout->key.bindings[key.binding_count];"
> 
> Do we need push constants in the pipeline layout cache? I imagine we'd
> only use these for internal shaders, but we wouldn't need to go
> through the pipeline layout cache for those.

No, we don’t, it was just convenient. As an aside, maybe we might try using them for application shaders too?

- Jan