Re: [whatwg] Canvas in Workers

On 2013/01/04 9:46, Gregg Tavares wrote:
> On Tue, Dec 11, 2012 at 9:04 AM, Ian Hickson <ian@hixie.ch> wrote:
>
>> On Tue, 11 Dec 2012, Gregg Tavares (社ç~T¨) wrote:
>>> In WebGL land we have creation attributes on the drawingbuffer made for a
>>> canvas. Example
>>>
>>>     gl = canvas.getContext("webgl", { preserveDrawingBuffer: false });
>>>
>>> We're working out the details on how to set those options for the case
>>> where we have 1 context and multiple canvases.
>>>
>>> The particular option above would apparently be a huge perf win for
>>> canvas 2d for mobile. Which suggests that whatever API is decided on it
>>> would be nice if it worked for both APIs the same.
>> What does it do?
>>
> Effectively it makes the canvas double buffered.

The reason for this attribute and defaulting it to false, is so that
tiled renderers can avoid copying the area of the previously-rendered
drawing buffer corresponding to the current tile, into tile memory prior
to rendering. Avoiding this copy is a big performance and power win for
tiled renderers. As far as I am aware every mobile GPU, with the
exception of NVIDIA's Tegra, is a tiled renderer so supporting them is
very important.

I would expect these wins to be equally important when doing animation
in Canvas2D as I would double buffering to to avoid flicker.

Regards

    -Mark

-- 
注意：この電子メールには、株式会社エイチアイの機密情報が含まれている場合
が有ります。正式なメール受信者では無い場合はメール複製、 再配信または情
報の使用を固く禁じております。エラー、手違いでこのメールを受け取られまし
たら削除を行い配信者にご連絡をお願いいたし ます.

NOTE: This electronic mail message may contain confidential and
privileged information from HI Corporation. If you are not the intended
recipient, any disclosure, photocopying, distribution or use of the
contents of the received information is prohibited. If you have received
this e-mail in error, please notify the sender immediately and
permanently delete this message and all related copies.

Received on Wednesday, 9 January 2013 02:51:40 UTC