Fix / double-copy for Safari tilemap bug when rendering with delta scrolling #1498
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This might fix a safari issue; it also avoids repeatedly setting the [same] composition operation and saving/loading context states.
- This change uses a secondary canvas and rectangle clearing instead of a 'copy' composition on the same canvas. This should hopefully address the flickering issue in Safari and Safari Mobile
- Memory optimization of delta-scroll shifting. - The copy canvas is shared between all TilemapLayers - The copy is done in segments to reduce the memory usage of the copy canvas. Currently this is a 1/4 ratio. - Device has the feature (by browser) check to see if bitblt works - TilemapLayer will automatically enable the double-copy as needed - Device.whenReady can be used to override the device value
- Updated shiftCanvas usage for consistency with renderSetting access
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Rather than ua sniffing this should be quite simple to test for by creating a canvas, drawing, performing the copy onto itself and checking the resulting pixel values I'd have thought? |
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@photonstorm That is indeed the "correct" approach - and as admitted the current UA approach may miss out on Chrome for iOS, etc. (It should probably use iOS -> force double copy.) I'm just shy on a device on hammer out the exact details of the failing case. |
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Sure no worries, I'll add the check in. |
The `canvasBitBltShift` detection is updated not to pick up any iOS browsers. This should eliminate false-positives for Chrome for iOS, eg. Defaulting to using the double-copy is "safer", even if slightly less optimal. (A proper feature check should still be added.)
(Previous changeset not pushed correctly)
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That update (the "real" one) should make it default to a double-copy except when using a known-to-work browser not on iOS. A proper feature check would be better, but I'm not entirely certain of the exact minimal reproduction case that I can verify/test locally. (Patches to While defaulting to a double-copy isn't the most "ideal" it is still able to dramatically benefit from reduced tile redraw (and on a desktop system performs on par with the single bitblt copy); so these last updates err on the side of caution. |
Fix / double-copy for Safari tilemap bug when rendering with delta scrolling
Should fix #1439 (comment) - with automatic selection based on browser detection.