Global texture co-ordinates sometimes distorted when setting worldOrientation #48374

New Issue

John Topple · 2016-05-08T15:03:11+02:00

John Topple commented

2016-05-08 15:03:11 +02:00

System info
Windows 7
Nvidia geforce GTX 550 ti

blender version
2.77 and before

description

I don't usually use AlignAxisToVect() since it often gives buggy results if you use the Y axis, so I usually use something like the following:

lerp_speed = 0.02
target_vector = target.worldPosition.copy() - own.worldPosition.copy()

own.worldOrientation =  own.getAxisVect([0.0,1.0,0.0]).lerp(target_vector,lerp_speed).to_track_quat("Y","Z")

worldOrientation is a 3x3 matrix and .to_track_quat produces a Quaternion so maybe I shouldn't be able to do this, but it usually works fine.
However, when the camera moves in to a certain position using this method the global texture co-ordinates become distorted causing flickering or stretching. This affects normal materials, nodes materials, and dynamic shadows, basically anything which depends on global texture co-ordinates.

To avoid it I can convert the Quaternion to a 4x4 matrix and use it to set the worldTransform instead, but I'd like to know what causes the problem with setting orientation with Quaternions.

Here are two blend examples:
global_co-ordinates_problem.blend
This is the problem blend.
global_co-ordinates_safe2.blend

And here is the same one with 4x4 matix method. press play and wait until it rotates to 90 degrees. The texture will get distorted.

I don't know what causes the problem, but it might be better to disallow setting orientation by Quaternion if no one else knows the reason.

**System info** Windows 7 Nvidia geforce GTX 550 ti **blender version** 2.77 and before **description** I don't usually use AlignAxisToVect() since it often gives buggy results if you use the Y axis, so I usually use something like the following: ``` lerp_speed = 0.02 target_vector = target.worldPosition.copy() - own.worldPosition.copy() own.worldOrientation = own.getAxisVect([0.0,1.0,0.0]).lerp(target_vector,lerp_speed).to_track_quat("Y","Z") ``` worldOrientation is a 3x3 matrix and .to_track_quat produces a Quaternion so maybe I shouldn't be able to do this, but it usually works fine. However, when the camera moves in to a certain position using this method the global texture co-ordinates become distorted causing flickering or stretching. This affects normal materials, nodes materials, and dynamic shadows, basically anything which depends on global texture co-ordinates. To avoid it I can convert the Quaternion to a 4x4 matrix and use it to set the worldTransform instead, but I'd like to know what causes the problem with setting orientation with Quaternions. Here are two blend examples: [global_co-ordinates_problem.blend](https://archive.blender.org/developer/F309770/global_co-ordinates_problem.blend) This is the problem blend. [global_co-ordinates_safe2.blend](https://archive.blender.org/developer/F309771/global_co-ordinates_safe2.blend) And here is the same one with 4x4 matix method. press play and wait until it rotates to 90 degrees. The texture will get distorted. I don't know what causes the problem, but it might be better to disallow setting orientation by Quaternion if no one else knows the reason.

John Topple commented

2016-05-08 15:03:11 +02:00

Changed status to: 'Open'

John Topple commented

2016-05-08 15:03:11 +02:00

Added subscriber: @Pickledtezcat

John Topple commented

2016-05-08 18:23:23 +02:00

I'd like to know if anyone else can repeat the bug using the example file. I tried using a matrix transform but actually it didn't improve the situation.

Here are some videos of other times when the same bug cropped up in my games:
https://youtu.be/2d8__t0WMUg?t=34s
https://youtu.be/G4cSvF7bAaM?t=1m22s

I've never heard anyone else report this problem though. It can't be my computer though, the graphics card is good enough, and I've updated to the latest drivers...

I'd like to know if anyone else can repeat the bug using the example file. I tried using a matrix transform but actually it didn't improve the situation. Here are some videos of other times when the same bug cropped up in my games: https://youtu.be/2d8__t0WMUg?t=34s https://youtu.be/G4cSvF7bAaM?t=1m22s I've never heard anyone else report this problem though. It can't be my computer though, the graphics card is good enough, and I've updated to the latest drivers...

John Topple commented

2016-05-09 08:37:55 +02:00

I confirmed this on a computer at work rocking a crappy Intel graphics card. It's not related to drivers or graphics cards.

My guess is that it's something to do with the camera transform matrix during rendering...

I confirmed this on a computer at work rocking a crappy Intel graphics card. It's not related to drivers or graphics cards. My guess is that it's something to do with the camera transform matrix during rendering...

Sergey Sharybin commented

2016-05-17 10:48:49 +02:00

Added subscriber: @Sergey