[Mesa-dev] [PATCH V3 05/13] mesa: Add validation helpers for new indirect draws
chrisf at ijw.co.nz
Fri Nov 15 20:07:57 PST 2013
I don't have access to another implementation at the moment -- can you test?
On Wed, Nov 13, 2013 at 9:57 AM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> On 11/12/2013 12:35 PM, Paul Berry wrote:
>> On 12 November 2013 12:13, Kenneth Graunke <kenneth at whitecape.org
>> <mailto:kenneth at whitecape.org>> wrote:
>> It would be great to put a citation for this:
>> /* From the ARB_multi_draw_indirect specification:
>> * "INVALID_VALUE is generated by MultiDrawArraysIndirect or
>> * MultiDrawElementsIndirect if <primcount> is negative."
>> * "<primcount> must be positive, otherwise an INVALID_VALUE error will
>> * be generated."
>> These beg the question of whether 0 is allowed. Usually I interpret
>> "negative" as < 0, "positive" as >= 0, and "strictly positive" as > 0.
>> So I think zero should be allowed, and I don't see a contradiction.
>> The only text I can find in 4.3 and 4.4 just reiterate that it needs to
>> positive, and I don't see any text defining "positive."
>> In the absence of text defining "positive", shouldn't we go with the
>> definition used by mathematicians? According to
>> "positive" means strictly greater than zero.
> Mathematicians are inconsistent in their use of terminology. Positive
> can mean either > 0 or >= 0 depending who you talk to and in what
> context. And the GL specification authors are notoriously non-precise.
>> If anyone is aware of a competing implementation that accepts a
>> primcount of 0, then I'd be open to following the behaviour of the
>> competing implementation (and filing a spec bug). But otherwise I think
>> we should prohibit zero.
> Then I suppose I have to go test AMD or nVidia.
>> (Note: I brought this up last time the patch was reviewed:
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