Add toggleable per-frame bounding-volume updates for animated models (SkinningControl)

[Copilot]

Animated models retained their bind-pose bounding volumes throughout animation, causing incorrect frustum culling when poses extended beyond bind-pose extents.

SkinningControl changes

• setUpdateBounds(boolean) — opt-in flag (default false); no cost unless enabled.
• Software skinning: calls geometry.updateModelBound() after each CPU skin pass.
• Hardware skinning: position-only CPU skinning against BindPosePosition updates the BoundingBox in-place each frame without touching GPU buffers.
• setBoundingUpdateBudget(int) — caps vertices processed per frame; work resumes from a per-geometry cursor the next frame, committing the bbox only once a full pass completes. Default is Integer.MAX_VALUE (all at once, preserving previous behaviour). Values ≤ 0 are normalised to MAX_VALUE.

SkinningControl sc = model.getControl(SkinningControl.class);
sc.setUpdateBounds(true);
sc.setBoundingUpdateBudget(500); // process at most 500 verts/frame

Both flags are serialised in write()/read() for J3O persistence. The deprecated SkeletonControl is unchanged.

Test & example

• testIssue343() added to PreventCoreIssueRegressions: software-skinned Elephant, legUp animation, asserts world bound shifts from bind pose.
• jme3test/animation/TestAnimatedModelBound.java in jme3-examples: Elephant with yellow wireframe bbox overlay; press B to toggle updateBounds at runtime.

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[riccardobl]

@copilot make this toggleable, off by default, add a visual example in jme3-examples

[Copilot]

@copilot make this toggleable, off by default, add a visual example in jme3-examples

Done in commit f4661dc.

• Added setUpdateBounds(boolean) / isUpdateBounds() to both SkinningControl and the deprecated SkeletonControl. The flag defaults to false, so existing behaviour is unchanged.
• The flag is also serialized in write()/read() so it persists in J3O files.
• Added jme3test/animation/TestAnimatedModelBound.java as a visual example: the Elephant model plays its "legUp" animation while a yellow wireframe box shows the world bound. Press B to toggle updateBounds on/off and see the box either track the animated pose or stay stuck at the bind pose.

[riccardobl]

@copilot undo the changes to the deprecated SkeletonControl, lets implement and test this only for the new SkinningControl

[Copilot]

@copilot undo the changes to the deprecated SkeletonControl, lets implement and test this only for the new SkinningControl

Done in commit 166a5d7. All changes to SkeletonControl have been reverted to its original state. The setUpdateBounds/isUpdateBounds feature now exists only in SkinningControl.

[riccardobl]

This partially defeats the point of having hardware skinning, can you distribute the bbox update in multiple frames by allowing the developer to set a maximum boundingUpdateBudget to decide how many vertices are considered per frame when updating the bounds?