Rapid and disorientating camera movement.

[fizzroy]

Describe the bug
Camera movement is fine as long as I move the mouse slowly and evenly. However, If I pass a certain speed threshold the camera swings widely leaving me completely lost. There is a precise moment, when I move the mouse that, when passed, makes the camera swing to the side with great speed. The camera movement doesn't increase the same way my mouse movement does, rather, it explodes past a certain point.

Changing the in-game mouse sensitivity does not affect this behavior.
Changing the FPS limit to 60/120/240 does not affect this behavior.

I've seen two other issues that describe this problem but they are closed. This is werid, as the problem is very much alive.

Save-game/Log-file/Screenshots/Video
If you need it, I can provide you with a video, but the description is pretty much on point.

Application log
I don't have any logs for this.

[Try]

HI, @fizzroy and thanks for report!

If you need it, I can provide you with a video, but the description is pretty much on point.

YES! Please provide a video, and as much detail as you can - while there were reports, I was never able to observe or reproduce the issue myself so far.

[fizzroy]

Here's the link to the YouTube recording of the issue. I'm trying to play as I usually do but any mouse movement faster than snail's pace swings my camera widely to the sides. The floaty movement continues even after I stopped moving the mouse. I'm currently playing Gothic 1 and there is no such issue. Gothic 2: NotR also works fine. It's just the Open Gothic that suffers from those wide swings and floaty camera.

[fizzroy]

I thought I'd run some tests. My mouse has a 1k polling rate and the sensitivity is set to 6k dpi - perfect for my 2550x1440 screen. So I switched the polling rate all the way to 125 - no change. I turned down the dpi to 1500 - big change, the swings are there but they are now almost non-existent. I ran the game with 2000, 2500, 4000 and 6000dpi and the swings get worse and worse until the game becomes completely unplayable. So the bug is there but it manifests the most when the player is using a high dpi setting in their mouse. The game can't handle high dpi settings but playing with anything below 3000-4000 isn't great as I have to "pick up" the mouse to move the character around.

[Try]

Thanks for the video @fizzroy !

I don't really have a mouse to math such dpi (using simple office mouse here), however base on a footage I have a theory, that windows doesn't discard mouse events properly, when game reposition mouse to the middle of the screen.

May you please check build for e9dd4f9, if it works better for you?

[fizzroy]

I think the build has failed. There are no files to download.

[Try]

@fizzroy

Linux build hit timeout. Here windows binary: https://ci.appveyor.com/project/Try/opengothic/builds/53359946/job/svd9ojfief563psi/artifacts

[Try]

Something I've forgot to ask: are you on windows or other OS? Asking since I've made path assuming windows :D

[Nindaleth]

The floaty movement continues even after I stopped moving the mouse.

While I can't reproduce the rapid camera movement issue on Linux with ~1600 DPI mouse, I agree with this comment; the "rotation-end" movement is nicely fluid but it takes too long to complete/stop.

---

Actually, I convinced my Windows-using friend to try OpenGothic and he didn't like the camera, even recorded a comparison video (but wouldn't go as far as to report the issue to the project). He says he moved the mouse the same way in both following videos.

Original:

Gothic2_original_C9Y9iNagHT.mp4

OpenGothic:

Gothic2Notr_OpenGothic_VLuupk0vaO.mp4

His comments on what he didn't like in OpenGothic:

• after the rotation starts, the camera is "thrown" after the character, instead of fluid rotation (or even a fast one) the viewport just jerks/skips/is yanked to the side (seems to me exactly what @fizzroy describes as rapid camera movement)
• the camera movement is too disconnected from the player character (in original the camera follows PC's eyesight much closer, in OpenGothic it takes a bit of time to start following and then at the end takes too much time to complete the rotation)

[Try]

@Nindaleth thanks for information!

For "floaty" rotation, it's actually attempt to respect camera velocity in the game (see Camera::followAng).
Velocity = 2 by default, and unit of measurement is unknown - so it's essentially something arbitrary. There is also clamp at 45deg.

Maybe it's better to lock the camera, when hero is movable, and respect speed only for interactions with objects.

[Try]

@Nindaleth

Maybe vanilla uses different base velocity for different rotation axis. And velo_rot acts as global multiplier rather..
Can you, please have a look at path:

diff --git a/game/camera.cpp b/game/camera.cpp
index 4019a37d..43a508d6 100644
--- a/game/camera.cpp
+++ b/game/camera.cpp
@@ -608,8 +608,9 @@ void Camera::followCamera(Vec3& pos, Vec3 dest, float dtF) {

 void Camera::followAng(Vec3& spin, Vec3 dest, float dtF) {
   const auto& def = cameraDef();
+  static float mulY = 4.f;
   followAng(spin.x,dest.x,def.velo_rot,dtF);
-  followAng(spin.y,dest.y,def.velo_rot,dtF);
+  followAng(spin.y,dest.y,def.velo_rot*mulY,dtF);
   }

 void Camera::followAng(float& ang, float dest, float speed, float dtF) {
@@ -620,7 +621,7 @@ void Camera::followAng(float& ang, float dest, float speed, float dtF) {
     return;
     }

-  static const float min=-45, max=45;
+  static const float min=-180, max=180;
   if(da>max+1.f) {
     shift = (da-max);
     }

It basically makes rotation around X-axis 4 times faster, to approximates vanilla behavior. Can't quite confirm if this is really right approach - dont have vanilla game runnable here.

[fizzroy]

I tried the 3584 build, the issue is still present. There may be some change but it is so insignificant that it makes no real difference. I’m using Win10 22h2. As @Nindaleth noted, the original Gothic 2 camera was very snappy and the movement was crisp. In opengothic it is way too floaty and this additional acceleration really kills it for me. @Try if possible, please try getting some high DPI mouse, this would allow you to test this yourself and really speed up the testing. @Nindaleth's comparison is a perfect showcase for how the games handle camera differently.

[Try]

@fizzroy

I'm trying to play as I usually do but any mouse movement faster than snail's pace swings my camera widely to the sides

and here that Nindaleth described:

, I agree with this comment; the "rotation-end" movement is nicely fluid but it takes too long to complete/stop.

Maybe I didn't fully understood you, but my read was that camera rotation is

1. irregular
2. too fast

and in case of Nindaleth, opposite - camera is too slow.

At first I've looked at irregularity - and it likely fixed now on windowsapi side (need to do adjustment on linux/osx).
For camera speed, it's hard to make usable experiment there, what I've done so far:

• snapping (Risen style) - looks totally not like gothic, probably wrong
• linear interpolation of angles - also look wrong
• non-linear blend-interpolation - better, this is what we have today.
  • blend can be compared frame-by-frame, when player opening/closing inventory. It's a good test, as inventory requires only one button click, and not persistent movement of the mouse. Inventory test passes.

Now I'm considering, since inventory can test only one axis(top-down) of rotation, maybe we can boost left-right rotation and achieve something close to case of default camera. And if it break MOBSI/jump cameras - that is less of a problem.

If you want - can schedule another build with that patch.