Naaah, it’s not that. The OSes draw code already handles that at a much lower
level. You’re just creating what is a maximum update throttle. You’re not
blitting pixels in a video card driver.
You can try my simple approach and just declare the next update time to be the
current time + 1 second. It should work without screen flicker at all.
We’re not doing low level code. As far as i know, the MacOS code has a triple
buffered system that already handles that.
> On Oct 23, 2020, at 10:51 AM, Andreas Falkenhahn <andr...@falkenhahn.com>
> wrote:
>
> The problem with that approach is that I'd need to find out the monitor's
> refresh rate in order to calculate "nextUpdateTime" and I'm not sure if I can
> get this information from all monitors reliably.
>
> On 19.10.2020 at 00:09 Alex Zavatone wrote:
>
>> It shouldn’t be too hard to roll your own simply based on milliseconds of a
>> timer.
>
>> Even a simple
>
> if (myMilliseconds >> nextUpdateTime) {
>> [updateObject doThatUpdate];
>> nextUpdateTime = myMilliseconds + msThrottle;
>> }
>
>> lets you get a basic throttle.
>>
>> Cheers,
>> Alex Zavatone
>
>>> On Oct 15, 2020, at 2:13 PM, Andreas Falkenhahn via Cocoa-dev
>>> <cocoa-dev@lists.apple.com> wrote:
>
>>> I'm drawing inside an NSView by simply setting its layer's contents to a
>>> CGImage which is updated for every frame, e.g. something like this:
>
>>> dp = CGDataProviderCreateWithData(NULL, frameBuf, frameBufSize, NULL);
>>> im = CGImageCreate(frameWidth, frameHeight, 8, 32, frameStride,
>>> theColorSpace, (CGBitmapInfo) kCGImageAlphaNoneSkipFirst, dp, NULL, FALSE,
>>> kCGRenderingIntentDefault);
>
>>> view.layer.contents = (id) im;
>>> CGImageRelease(im);
>>> CGDataProviderRelease(dp);
>
>>> This works fine except that there is no throttle so this will draw as fast
>>> as the CPU allows, which of course is a waste of CPU cycles because the
>>> monitor only refreshes a certain amount of times per second.
>
>>> So is there a convenient way to throttle drawing to the monitor's refresh
>>> rate or does this have to be done the hard way by querying the monitor's
>>> refresh rate and then setting up a timer which draws in exactly those
>>> refresh intervals or how should this be done?
>
>>> Note that I'd like to avoid using OpenGL or Metal or whatever is the
>>> standard nowadays but I'm mainly interested in an AppKit solution...
>
>>> --
>>> Best regards,
>>> Andreas Falkenhahn mailto:andr...@falkenhahn.com
>
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>
>
>
> --
> Best regards,
> Andreas Falkenhahn mailto:andr...@falkenhahn.com
>
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