On 01/01/2013 09:20 AM, Matt Turner wrote:
On Wed, Dec 19, 2012 at 8:40 PM, Matt Turner <matts...@gmail.com> wrote:
The ES 3.0 and GL 3.3+ specs say:
A new sampler object is created by binding an unused name to a
texture unit.
[...]
vvvvvvvv
The names are marked as used, for the purposes of GenSamplers only,
but they acquire state only when they are first used as a parameter
to BindSampler, SamplerParameter*, GetSamplerParameter*, or IsSampler.
When a sampler object is first used in one of these functions, the
resulting sampler object is initialized with a new state vector,
comprising all the state and with the same initial values listed in
table 6.10.
^^^^^^^^
We're not handling the requirement to initialize the object specified
in the 2nd paragraph, but my real question is --
Can IsSampler ever return false if given a name returned by
GenSamplers? Does 'acquire state' mean becomes a sampler object? These
paragraphs seem contradictory.
So to close the loop on this, I think we're handling everything
properly after all. At least, it's impossible to tell that we're doing
it wrong, which is indistinguishable from doing it right. :)
Please someone confirm my logic:
The spec says that sampler objects only "acquire state" when used as a
parameter to BindSampler, SamplerParameter*, GetSamplerParameter*, or
IsSampler. But these are the only functions that in which a sampler id
returned from GenSamplers can be used, and since the functions used to
detect if sampler objects have state have the side-effect of causing
them to acquire state, it's safe to just do initialization in
GenSamplers (which is what we do).
Maybe there's some other case we're not handling properly? Hardly
seems worth finding.
The paragraph above seems crystal clear to me: IsSampler should always
return true for a name created by GenSamplers, since it isn't a
different kind of object, and calling IsSampler causes it to be
created/initialized (at which point it *is* a sampler object).
So I think initializing it in GenSamplers is fine.
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