[0.17.25] Coal deposits blinks on a minimap when char moves

[Dixi]

Just noticed that coal deposits blinks on a minimap when a char moves.

100% reproducible. Restarting client, loading another save, generating new map - it always blinks.
Only coal. Other minerals - no.
It happens only during walking animation (or moving in a car). As soon as char stops blinking stops.

Win 7x64, nVidia 1060 3Gb. 1920x1080. Steam client.

It looks like, when a char moves, some frame is drawn only brown, on deposit spot, without black.
I've captured video with fraps, - it blinks on a video too, but I did not found a way yet to see it frame by frame to find incorrect looking frame.
Here is a video: https://youtu.be/pjTlge9vwt0
Mind that only coal blinks, while copper and stone (and others) - not.

Just updated graphics driver to 419.67 - nothing changes.

[TruePikachu]

Provide logs and video.

[DaleStan]

It's very subtle, but now that you point it out, I see it too. Depending on what speed I'm moving, and what the background landscape is, I can also see it in some of the other ores.

However, I'm going to blame my eyes, my monitor, or maybe my video card, rather than Factorio. I see very similar flicker in the attached GIF.

[tehfreek]

You're probably seeing this effect (move the browser window around to see it). Patterns of alternating light and dark pixels are very problematic for LCDs of any type to display movement of.

[Dixi]

Made a video - https://youtu.be/pjTlge9vwt0

You're probably seeing this effect (move the browser window around to see it). Patterns of alternating light and dark pixels are very problematic for LCDs of any type to display movement of.

Do you mean that when a minimap image is shifted by one pixel in any direction I see blinking, due to fact that white and black pixels are swapping places? And that same effect is not visible/notable for other ores because of less contrast difference?

If this is not a visualization bug, then we can call is visualization glitch that looks like bug. I think it can be avoided some way - ether by shifting minimap image by 2 pixels, or maybe, by changing contrast of minmap coal.

[posila]

Is the effect captured on the video? Because I don't see any problem (watching at fullscreen 1080p, of course)

[tehfreek]

I took another look at the video. On my IPS monitor there is blinking, on my TN monitor the image is rock solid.

[Shogal]

Also, if minimap is zoomed (or scale setting is set not to 100%) - pattern becomes something strange, not checkerboard anymore.
I think, resource patches rendering on minimap should respect zoom factor and render pixels according to final viewport coordinates (display screen coordinates), not according to position on minimap. This will also solve blinking while walking.

[Dixi]

Is the effect captured on the video? Because I don't see any problem (watching at fullscreen 1080p, of course)

Yes I see same effect on video.

As some ppl says blinking probably happen due to monitor white-to-black latency.
Since coal on a minimap is drawn by interchange 1-0-1-0-1 of black and usually bright pixels. When this pattern is shifted for 1 pixel, monitor have to switch dots from full bright to almost full dark, and back on next step. Since it's the worst scenario for some types of monitors, this cause blinking.

As someone mentioned, it depends on matrix type, and not visible on fast TN monitors. I have rather old Samsung MVA, and here it's clearly visible.

[Shogal]

Even more, sometimes static 1px checkerboard image flickers when i just rotate my head quickly left and right or shake my screen. So it's not only matrix problem, but also an optical illusion. Unfortunally, i have no printer to check whenever this works on paper too or on screen only.
Also, i made a quick demo to test different methods of reducing flickering, but every method has it's own disadvantages and probably has different effect on different screens: https://codepen.io/anon/pen/wZzzWo/left

[Dixi]

Very cool demo picture!

On my display both Parity and Step 2px works well - no blinking.

On slow movement speed all methods have some disadvantages, but better then Normal.
Parity gives some shimmering on deposit borders, while in Step 2px map movement is a little less smooth.
I think Parity is slightly better, and both methods are definitely better then Normal.

Since this thread is classified not a bug, could be nice if you'll offer your way of minimap drawing to dev's some way. I wonder is it possible to change draw method in a mod?