rotated_by apply on a textured shape seems to be broken

[agrignard]

Describe the bug Problem with rotated_by on textured geometry (maybe on all geometry but we didn't realize it?) Run this model

model NewModel

/* Insert your model definition here */

global{
	file imageRaster <- file('./../images/Kent_Sketches.png');
}

experiment TEST{
	output{
		display goodwithCam2 type:opengl
		{
			graphics "image" {
				draw rectangle(500#px,500#px) rotated_by (cycle,{1,0,0}) texture:[imageRaster.path];
			}
		}			
	}
}

Can be tested running this picture_test.zip

Here is what I get with

draw rectangle(500#px,500#px) rotated_by (89,{1,0,0}) texture:[imageRaster.path]

and with

draw rectangle(500#px,500#px) rotated_by (90,{1,0,0}) texture:[imageRaster.path]

Expected behavior I would assume to see a spinning image (the idea was to draw an image as a white board to applying a 90° rotation on the X axis. However I see that the picture is flipped.

[AlexisDrogoul]

Hi, Not sure to understand this bug report. Is it a problem with

• the texture being flipped or
• the shape not being correctly rotated ?

Besides, what does (maybe on all geometry but we didn't realize it?) mean ?

[agrignard]

I mean if you just draw a non textured rectangle we don't see that there is a problem as the geometry is "invariant" in term of rotation

[AlexisDrogoul]

Sorry, I don't get it. The only 3D geometry I know which is 'invariant' in terms of rotation is the sphere. Rotating a rectangle around the x-axis should rotate the geometry, no ?

[agrignard]

Yes it will rotate the geometry what I mean by invariant is the texture (e.g a pure white picture is invariant)

I just did a gif that can maybe help to track the issue.

So first I display my rotated picture with the draw rectangle(500#px,500#px) rotated_by (89,{1,0,0}) as 90 doesn't work as explained below.

However I just discover that if I inspect the agent (so I guess the size of the window of the display change then the picture is being flipped no way to have it back in the right orientation unless i relaunch the experiment

[agrignard]

It also happens (the flipped of the texture) if I switch to fullscreen

[AlexisDrogoul]

Now tracked under #2209 -- for the OpenGL adventurous !

[AlexisDrogoul]

Reopening this issue for the next round of development on GAMA 2.0

[AlexisDrogoul]

There is actually a place in the code (in OpenGL.java) where we declare:

private final Rotation3D currentTextureRotation = Rotation3D.identity();

This field is then used to provide a "best guess" at how to rotate the texture according to the rotation of the object. I'm not quite sure to understand why it's failing here. ..

[agrignard]

Spent some time on this, few thing have changed except that the flip now happens between 90 and 91 instead of 89 and 90 degrees...

[AlexisDrogoul]

I have pushed a commit that adds a new preference (pref_texture_orientation), which can be set or not in models. When set (default value), the textures are applied using a heuristic "best guess" algorithm, like now. When unset, no rotation/orientation is applied to the texture coordinates. This adresses your issue, but not applying any rotation also raises issues in some models, hence the possibility to set/unset this preference. I've added it in some models of the library by the way. Please test !