[Bug] Gun crosshair works correctly only in native resolution

[voradori]

Description

Crosshair is behaving wrong on X-axis with internal resolution >1

Expected behavior

Crosshair correctly follows mouse cursor and real ingame aim mark on any GPU render scale

Actual behavior

a)
Crosshair's position on X axis is divided by N when using N image scaling.
E.g. when scale = 2, and mouse is in the center, crosshair is between cursor\mark and left screen edge

Y axis works as expected.
It's just crosshair X position draw bug - real aim mark is where it should be.

b)
There is also a very slight difference between crosshair and aim mark (and mouse cursor when windowed) even on native internal resolution - the closer crosshair to left\right edge is, the bigger is the difference. But it's very minor thing - the biggest difference is about 0.5 cm on a standard fullhd 24" screen

Steps to reproduce the bug

1. Set input device 1 to Guncon
2. Run Time Crisis to calibration screen
3. Shoot at the aim to spawn red aim mark
   a) 4. Set internal gpu resolution to any value > 1
   b) 4. Let Internal gpu resolution at 1
4. Move crosshair to Left and Right edges (try in both windowed and fullscreen)

Version/Commit

0.9.44.1 beeee12 SW\HW core
(There's no working crosshair and even shots under mouse cursor on HW core for gl\vulcan renderer, even in SW mode. DX renderers works with same problems as SW core)

Core options

Internal GPU Resolution = 2
Skip Bios = True
Widescreen hack = true

Environment information

• OS: Win10 Pro x64 1809
• Retroarch 1.7.5

[Jj0YzL5nvJ]

Is the widescreen hack. That option only works correctly on some 3D games. The "aim" is a 2D element.

[voradori]

don't judge with no testing.
calibration screen is pure 2d.
and everything is the same for WS hack off

problem a

problem b

as you can see, ws hack has no influence
that's same for both cores on any working renderer

[Jj0YzL5nvJ]

This recall me a very old bug on Debian with the first generation of Intel HD Graphics...
What is your GPU and driver version?

[voradori]

GTX 980, driver 416.94

[SirFritz]

I also have this issue, and on higher resolutions than 2x crosshair disappears completely. I have also experienced the slightly out of sync crosshair on the sides of the screen.

GTX970 417.71

[ggrtk]

Issue has been diagnosed to screen space scaling in input_handle_lightgun() and input_handle_lightgun_touchscreen() in input.cpp. The scaling formula needs to be modified to account for the internal resolution scale, horizontal overscan cropping, and potentially the initial/last scanlines setting.