Add MipMaps to PBRTerrainAdvancedTest.java (#2289)

This test case has some noisey rendering that are due to not setting mipMaps on the TextureArray.

So I added the MinFilter.Trilinear to fix this issue, and also added MagFilter.Bilinear.

jme3-examples/src/main/java/jme3test/terrain/PBRTerrainAdvancedTest.java

@@ -52,6 +52,8 @@
 import com.jme3.texture.Image;
 import com.jme3.texture.Texture;
 import com.jme3.texture.Texture.WrapMode;
+import com.jme3.texture.Texture.MagFilter;
+import com.jme3.texture.Texture.MinFilter;
 import com.jme3.texture.TextureArray;
 import java.util.ArrayList;
 import java.util.List;
@@ -279,10 +281,10 @@ private void setUpTerrainMaterial() {
         TextureArray metallicRoughnessAoEiTextureArray = new TextureArray(metallicRoughnessAoEiMapImages);
 
         //apply wrapMode to the whole texture array, rather than each individual texture in the array
-        albedoTextureArray.setWrap(WrapMode.Repeat);
-        normalParallaxTextureArray.setWrap(WrapMode.Repeat);
-        metallicRoughnessAoEiTextureArray.setWrap(WrapMode.Repeat);
-
+        setWrapAndMipMaps(albedoTextureArray);
+        setWrapAndMipMaps(normalParallaxTextureArray);
+        setWrapAndMipMaps(metallicRoughnessAoEiTextureArray);
+        
         //assign texture array to materials
         matTerrain.setParam("AlbedoTextureArray", VarType.TextureArray, albedoTextureArray);
         matTerrain.setParam("NormalParallaxTextureArray", VarType.TextureArray, normalParallaxTextureArray);
@@ -430,6 +432,12 @@ private void setUpTerrain() {
         rootNode.attachChild(terrain);
     }
 
+    private void setWrapAndMipMaps(Texture texture){
+        texture.setWrap(WrapMode.Repeat);
+        texture.setMinFilter(MinFilter.Trilinear);
+        texture.setMagFilter(MagFilter.Bilinear);
+    }
+
     private void setUpLights() {
         LightProbe probe = (LightProbe) assetManager.loadAsset("Scenes/LightProbes/quarry_Probe.j3o");