Odd number screen resolution sometimes lead to garbled rendering

[bitinn]

aka iPhone 6 resolution (375 × 667 pt).

Screen resolution with even number (376 × 668) doesn't seem to suffer from the problem.

The strange thing: it doesn't happen (or become noticeable) on all maps, only some, even though they have similar tilesets and map dimensions.

[karai17]

Are you flooring your draw positions?

[bitinn]

I want to say I did because I am usually mindful with this sort of things...

But I fail to reproduce this problem after tuning a few layer related operations recently. I will re-open if it comes up again.

[bitinn]

Weird, this problem only happens on iMac but not my Macbook Air, both non-retina, both use the same version of OS X and LOVE. Source code versioning is managed by git so I am confident they are the same.

I can think of only 2 places where I need to floor explicitly, camera position and draw range, they both are. What else should I look out for?

UPDATE: actually all maps on iMac suffer from this odd number resolution problem, some are just subtle enough so I didn't catch them initially.

[karai17]

Draw position
On Apr 24, 2016 2:45 PM, "David Frank" notifications@github.com wrote:

Reopened #106
#106.

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#106 (comment)

[bitinn]

I am not getting what you mean. None of the tiles in above image are drawn using custom layer/object layer, they are just drawn through tile layers, by calling Map:draw() (it accepts no parameters), no additional scale or rotation are applied. Camera translates the map using floored integer.

I fail to find anything on draw position in your api doc or Tiled, love.graphic.draw() is the only thing that takes a draw position but how could a sprite in custom layer mess up tiled layers?

[karai17]

Sorry, I was half asleep when I wrote that. If your camera (translation) is floored, then it shouldn't be causing weird artifacts like that.

[bitinn]

No worries, I did floored the camera position when I move it, I will have to see if it has anything to do with camera creation using non-integer number.

Still it's kinda strange I can only reproduce it on iMac...

ref: https://github.com/vrld/hump/blob/master/camera.lua#L63-L69

[bitinn]

I got it now, both hump.camera and gamera are doing / 2 internally, this means we need at least an even number to ensure translation is an integer.