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Re: [Public WebGL] Some WebGL draft feedback



On Jan 13, 2010, at 1:01 PM, Tim Johansson wrote:

> On 2010-01-13 20:43, Kenneth Russell wrote:
>> On Tue, Jan 12, 2010 at 8:00 PM, Mark Callow <callow_mark@hicorp.co.jp <mailto:callow_mark@hicorp.co.jp>> wrote:
>> 
>> 
>> 
>>    Kenneth Russell wrote:
>> 
>> 
>>        If an explicit wait is added to the API, what happens if the
>>        developer fails to call it before rendering with a different
>>        context? Do they get an exception or incorrect rendering results?
>> 
>>    Incorrect rendering. The exception checks would have the same
>>    performance and tentacle-spreading issues I raised before.
>> 
>> 
>> I don't think incorrect rendering results are an acceptable alternative. I also dispute whether the check to see if the given rendering context is "current" upon each graphics call would have any perceptible performance impact. We currently have and need such checks in the WebGL implementations for Safari and Chrome and they are negligible in cost.
>> 
> I agree that incorrect rendering is not good as it is not well specified. If an implementation manages to get it looking right without calling the sync function that behavior will quickly become required  since many authors will forget to call the sync functions.
> 
> That means the check is required and I don't see any real benefit of requiring a sync function to be called instead of just syncing implicitly. IMO we should not add functions to make authors think about everything that might be slow in some implementations.


We should discuss this Thursday. I really like Vlad's suggestion that we avoid supporting simultaneous rendering in favor of handling Canvas element as input images.

-----
~Chris
cmarrin@apple.com




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