AS3 AIR iOS - How to control when BitmapData is cached/uncached from the GPU?

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This question's kind of a 4-parter:

  1. Is it true that all BitmapData is immediately cached to the GPU as soon as it's created (even if it's never applied to a Bitmap or added to stage?)

  2. Does this still happen if the GPU texture buffer is already full? Bonus points: if so, what's the preferential swap method the GPU chooses to select which textures to remove from memory?

  3. If (1), then does setting the width/height of any BitmapData uncache it and/or does replacing its pixels therefore upload the new pixels to the same memory address on the GPU? Bonus: What if the size changes?

  4. To bring this all together, would a hybrid class that extends BitmapData but stores its actual data in a ByteArray be able to use setPixels/getPixels on itself to control upload/download from the GPU as necessary, to buffer a large number of bitmaps? Bonus: Would speed improve for actually placing them in Bitmaps if the instances of this class were static?

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iosiphoneactionscript-3flashgpu

1 Answers

0
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Here are some answers

  1. No. In AIR, you manually upload bitmaps to GPU and have control WHEN to do it
  2. As far as I've reached, if the buffer is full, you simply get an error for it - the GPU cannot make a choice what do to. Removing a random texture won't be nice if it's important to you, right? :)
  3. You can check for example Starling and how it uploads textures to GPU. Once you force it to do so, it doesn't care what you do with the bitmap. It's like making a photo image of an object so that you can just show it instead of explaining it with words. It won't matter if you change the object, the photo will be still the same.
  4. Simplified answer: no. Again - it's best to check out how textures are created and how you upload stuff to GPU.