Terrain.setLocked() does not work

Ali_RS · November 29, 2022, 1:27pm

Hi,

I noticed JME Terrain has a setLocked() method that claims to improve the performance by making terrain un-editable. (internally use Mesh.setStatic())

github.com

jMonkeyEngine/jmonkeyengine/blob/ec752f73b4f7b720cee1929a89d57cc1b04cf752/jme3-terrain/src/main/java/com/jme3/terrain/Terrain.java#L127-L133


      
          /**

           * Lock or unlock the meshes of this terrain.

           * Locked meshes are un-editable but have better performance.

           * This should call the underlying getMesh().setStatic()/setDynamic() methods.

           * @param locked or unlocked

           */

          public void setLocked(boolean locked);

it ends up calling TerrainPatch.lockMesh()

github.com

jMonkeyEngine/jmonkeyengine/blob/df9b204744fd1e3d36e73fa4421cd83dfcf76328/jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainPatch.java#L606-L612


      
          /**

           * Locks the mesh (sets it static) to improve performance.

           * If it is not editable, then unlock to make it editable.

           */

          public void lockMesh() {

              getMesh().setStatic();

          }

I enabled it but I did not notice any performance improvement and the terrain is still editable. I already checked and can confirm all buffers on the terrain meshes are set to Static usage.

Anybody knows why this does not work as expected?

tonihele · November 29, 2022, 3:10pm

I recall seeing somewhere that it is just a hint. Hint to GPU? It doesn’t prevent anything. It just allows the GPU to optimize, if it wants to. There is probably a lot of variation how it works in practice.

pspeed · November 29, 2022, 6:11pm

That is my understanding as well. Like, a “static” mesh is a holdover from a time when that mattered more. It seems to make no difference today.

…and I suspect the author of JME’s terrain stuff was confused as to its use when calling it “lock”. It definitely doesn’t lock anything. You can still edit a static mesh.