Fixes #3221.

There is however something strange in the upVector computation, which
doesnt to influence anything. It needs to be verified again with some
further tests

msi.gama.core/src/msi/gama/outputs/LayeredDisplayData.java

@@ -692,7 +692,6 @@ public void setCameraOrientation(final GamaPoint point) {
 		final GamaPoint c = point;
 		if (cameraOrientation != null) {
 			if (c.equals(cameraOrientation)) return;
-			DEBUG.OUT("UpVectors different: x " + point.x + " != " + cameraOrientation.x);
 			cameraOrientation.setLocation(c);
 		} else {
 			cameraOrientation = new GamaPoint(c);

ummisco.gama.opengl/src/ummisco/gama/opengl/camera/AbstractCamera.java

@@ -123,9 +123,6 @@ public abstract class AbstractCamera implements ICamera {
 	/** The use num keys. */
 	private final boolean useNumKeys = GamaPreferences.Displays.OPENGL_NUM_KEYS_CAM.getValue();
 
-	/** The Constant UP_Z. */
-	private static final GamaPoint UP_Z = new GamaPoint(0, 0, 1);
-
 	/**
 	 * Instantiates a new abstract camera.
 	 *
@@ -136,7 +133,7 @@ public AbstractCamera(final IOpenGLRenderer renderer2) {
 		this.renderer = renderer2;
 		// LayeredDisplayData data = renderer.getData();
 		// if (!data.isCameraUpVectorDefined() && !data.getCameraOrientation().equals(UP_Z)) {
-		setUpVector(0.0, 1.0, 0.0);
+		setUpVector(0.0, 0.0, 1.0);
 		// }
 		glu = new GLU();
 	}
@@ -235,6 +232,7 @@ public void setUpVector(final double xPos, final double yPos, final double zPos)
 
 	@Override
 	public void animate() {
+		// TODO : Y and Z seem to be exchanged... Probably something to look at (see #3221)
 		glu.gluLookAt(position.x, position.y, position.z, target.x, target.y, target.z, upVector.x, upVector.y,
 				upVector.z);
 	}

ummisco.gama.opengl/src/ummisco/gama/opengl/camera/CameraArcBall.java

@@ -48,15 +48,13 @@ public void updateCartesianCoordinatesFromAngles() {
 		final double sinT = Math.sin(factorT);
 		final double cosP = Math.cos(factorP);
 		final double sinP = Math.sin(factorP);
-		setPosition(getDistance() * cosT * sinP + target.x, getDistance() * sinT * sinP + target.y,
-				getDistance() * cosP + target.z);
+		final double radius = getDistance();
+		setPosition(radius * cosT * sinP + target.x, radius * sinT * sinP + target.y, radius * cosP + target.z);
 		// See #2854 -- see if putting this here does not restrict the moves using the mouse
 		if (flipped) {
-			setUpVector(-(-Math.cos(theta * Maths.toRad) * Math.cos(phi * Maths.toRad)),
-					-(-Math.sin(theta * Maths.toRad) * Math.cos(phi * Maths.toRad)), -Math.sin(phi * Maths.toRad));
+			setUpVector(-(-cosT * cosP), -(-sinT * cosP), -sinP);
 		} else {
-			setUpVector(-Math.cos(theta * Maths.toRad) * Math.cos(phi * Maths.toRad),
-					-Math.sin(theta * Maths.toRad) * Math.cos(phi * Maths.toRad), Math.sin(phi * Maths.toRad));
+			setUpVector(-cosT * cosP, -sinT * cosP, sinP);
 		}
 	}