System Information
Win8 64bit | gtx680
Blender Version
Broken: 2.73.9 51a60cb
Short description of error
This happens in Perspective View. When zooming in and get closer to the target surface, the more closer to it, the more likely that some draw parts will missing. However, increasing lens angle seems to improve it a bit.
Exact steps for others to reproduce the error
Open attached file, and draw on different parts.
The problem is that the brush collides with the center of the pixel only and not a rectangle in screen space.
To see this issue better try painting on a plane with a 2x2 texture image with a small brush.
I don't see this easily fixable unless we calculate screen space coordinate derivatives per pixel and this will increase the cost of painting a lot.
@Campbell Barton (campbellbarton), maybe you have a better idea here?
Ah, I see, so it isn't a sort of perppective-only issue actually, and same would happen in ortho, right? I believe this is about the algorthm as well at the beginning, but not so sure about that. Thanks for clarify.
Actually it was reported by two artists individually from my local community. I just help to translate and report here. :)
From brief discussion looks like we can't handle subpixel painting easily. It should be filed as limitation for now.
Correct, issue exists in any projection provided pixel size on screen is comparable or greater than brush size