Error in iOS10

Question

Nemesis OP

Created Oct ’16

Replies 11

Boosts 0

Views 3.5k

Participants 7

Code that previously worked fine, now emitts error after presenting drawable:

func draw() {
...
mainCommandBuffer.present(currentDrawable)
mainCommandBuffer.commit()
}

EXC_BAD_ACCESS on [CAMetalDrawable present]

with log error message:

[CAMetalLayerDrawable texture] should not be called after presenting the drawable.

There is no other info, and I have no idea what to try to fix. I'm no not calling "texture" after presenting drawable, it is last line in the method.

Does someone have a clue?

Thanks

Boost

Answer 1

dami1 OP

Oct ’16

Hi Nemesis,

I have the exact same issu since iOS 10. If you find something please post the answer.

Thanks

0

Answer 2

dami1 OP

Oct ’16

"Hi Again,

For me, it was just because I did not call draw() method after presenting the drawable.

What Apple documentation says about currentDrawable property of MTKView => "This value is updated at the end of every call to draw()." So once presented, the draw() method should be called in order to update the currentDrawable.

Your peace of code do not give me context enough to help you but I'm pretty sure that it's the same idea for you

Regards,

Damien

0

Answer 3

wcm OP

Oct ’16

You should only call need to call

draw()

if you've disabled the display link timer in the view (for example, by setting its

isPaused

property to

true

). Otherwise, the

MTKView

's delegate's

draw(in:)

method will be called, or if the view doesn't have a delegate, its own

draw(:)

method is called. All of your drawing should happen in the scope of one of these two methods. If you need to manually call

draw()

while the view is configured to draw automatically, that may indicate a problem with where/how you're doing your drawing.

0

Answer 4

dami1 OP

Oct ’16

Thank you wcm.

Yes it's the case. For the moment I'm calling draw() method manually and set isPaused to true. In fact I'm generating and processing images from raw data and show them on the flight in the MTKView. The image generation rate was greater than the GTKView configured framerate and the crashe was because I tried to present the same drawable twice.

Do you think that calling draw() method manually causes perfomance issue ? If so, should I present my drawable inside an overidden draw() method ?

Thanks

0

Answer 5

Nemesis OP

Oct ’16

Hey wcm,

In my case it is not related to draw() call, but I discovered that it may be somehow related to view resize. If one is not attempting to change size of the view rendering works, but at the moment when view frame is changed error pops up.

0

Answer 6

wcm OP

Oct ’16

Calling

draw()

manually doesn't have any negative performance implications; it's a legitimate way to use

MTKView

when you're not using its built-in timer. My point above was that you shouldn't need to manually call

draw()

if you're already getting regular callbacks to your

draw(:)

or

draw(in:)

methods, and that you should do all drawing and presentation in those methods or methods called by those methods.

0

Answer 7

wcm OP

Oct ’16

This may indicate that something regressed between iOS 9 and iOS 10. Can you please file a bug report with a version of your project that reproduces this issue?

0

Answer 8

gorillapie2000 OP

Nov ’16

Are there any more updates to this thread ?

I am facing the same issue in my project where I am using MTKView. ( used to work earlier on iOS 9.3, XCode 7.3.1 and now crashes with that

EXC_BAD_ACCESS on [CAMetalDrawable present]

with log error message:

[CAMetalLayerDrawable texture] should not be called after presenting the drawable.

The MTKView bounds are not being resized, neither am I calling draw() manually. There is no delgate set on MTKView so I guess I am falling back to MTKView's draw method.

// general calls

draw()

{

...

id<CAMetalDrawable> drawable = mView.currentDrawable;

...

[commandBuffer presentDrawable:drawable];

[commandBuffer commit];

}

0

Answer 9

wcm OP

Nov ’16

I never saw any bug reports related to this issue, so it hasn't been investigated. If you want to file a report and mention the number here, we can take a look.

0

Answer 10

gorillapie2000 OP

Nov ’16

Sure. Will file a bug report. Quick update : I swapped out my MTKView with a simple UIView embedded with a CAMetalLayer, and adjust a few initialization lines accordingly and the code works very well.

0

Answer 11

Starfia OP

Feb ’17

I don't know if it helps anyone, but I just started getting this error after overriding an MTKView's draw() method rather than draw(_ rect:), all other things equal.

1