Anim2dDemoApp.java

import com.jme3.app.SimpleApplication;
import com.jme3.material.Material;
import com.jme3.math.Vector2f;
import com.jme3.math.Vector3f;
import com.jme3.renderer.RenderManager;
import com.jme3.renderer.ViewPort;
import com.jme3.scene.Geometry;
import com.jme3.scene.Mesh;
import com.jme3.scene.VertexBuffer.Type;
import com.jme3.scene.control.AbstractControl;
import com.jme3.util.BufferUtils;

public class Anim2dDemoApp extends SimpleApplication {

  public static void main(String[] args) {
    new Anim2dDemoApp().start();
  }

  @Override
  public void simpleInitApp() {
    var quad = new Geometry("quad", createMesh());
    var mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
    var tex = assetManager.loadTexture("Materials/computers/BigScreen001_Anim2.png");
    mat.setTexture("ColorMap", tex);
    quad.setMaterial(mat);
    quad.setLocalTranslation(00, 00, 0);
    quad.scale(500);
    
    // cycle animation every 1 second
    quad.addControl(new AnimationControl(1, 2, 2));

    guiNode.attachChild(quad);
  }

  private Mesh createMesh() {
    var m = new Mesh();
    m.setBuffer(Type.Position, 3, BufferUtils.createFloatBuffer(new Vector3f(0, 0, 0f), new Vector3f(1, 0, 0f),
        new Vector3f(0, 1, 0f), new Vector3f(1, 1, 0f)));

    m.setBuffer(Type.TexCoord, 2, BufferUtils.createFloatBuffer(new Vector2f(0f, 0f), new Vector2f(1f, 0f),
        new Vector2f(0f, 1f), new Vector2f(1f, 1f)));

    m.setBuffer(Type.Index, 1, BufferUtils.createIntBuffer(2, 0, 1, 1, 3, 2));
    var normal = Vector3f.UNIT_Z;
    m.setBuffer(Type.Normal, 3, BufferUtils.createFloatBuffer(normal, normal, normal, normal));
    m.updateBound();
    return m;
  }

  private class AnimationControl extends AbstractControl {
    double maxTtl = 1;
    int sheetSizeX = 2;
    int sheetSizeY = 2;

    public AnimationControl(double maxTtl, int sheetSizeX, int sheetSizeY) {
      this.maxTtl = maxTtl;
      this.sheetSizeX = sheetSizeX;
      this.sheetSizeY = sheetSizeY;
    }

    double ttl = maxTtl;

    protected void controlUpdate(float tpf) {
      ttl -= tpf;
      if (ttl < 0) {
        ttl += maxTtl;
      }
      int n = (int) ((sheetSizeX * sheetSizeY / maxTtl) * (maxTtl - ttl));
      int i = n % sheetSizeX;
      int j = -1 + sheetSizeY - n / sheetSizeX;

      float stepX = 1f / sheetSizeX;
      float stepY = 1f / sheetSizeY;

      var mesh = ((Geometry) getSpatial()).getMesh();
      mesh.setBuffer(Type.TexCoord, 2,
          BufferUtils.createFloatBuffer(
              new Vector2f(i * stepX, j * stepY),
              new Vector2f(i * stepX + stepX, j * stepY),
              new Vector2f(i * stepX, j * stepY + stepY),
              new Vector2f(i * stepX + stepX, j * stepY + stepY)));
    }

    @Override
    protected void controlRender(RenderManager rm, ViewPort vp) {
    }

  }
}