FXAA: quality regression fix

FXAA wants input texture to use bilinear filtering
so it can be smoothed further, so allow filters to
request bilinear filtering.

jme3-core/src/main/java/com/jme3/post/Filter.java

@@ -409,6 +409,19 @@ public abstract class Filter implements Savable {
         return true;
     }
 
+    /**
+     * Override this method and return true if you want the scene (input) texture
+     * to use bilinear filtering or false to use nearest filtering.
+     * 
+     * Typically filters that perform samples <em>in between</em> pixels 
+     * should enable filtering.
+     * 
+     * @return true to use linear filtering, false to use nearest filtering.
+     */
+    protected boolean isRequiresBilinear() {
+        return false;
+    }
+    
     /**
      * returns the list of the postRender passes
      * @return

jme3-core/src/main/java/com/jme3/post/FilterPostProcessor.java

@@ -38,6 +38,7 @@ import com.jme3.renderer.*;
 import com.jme3.renderer.queue.RenderQueue;
 import com.jme3.texture.FrameBuffer;
 import com.jme3.texture.Image.Format;
+import com.jme3.texture.Texture;
 import com.jme3.texture.Texture2D;
 import com.jme3.ui.Picture;
 import com.jme3.util.SafeArrayList;
@@ -285,6 +286,12 @@ public class FilterPostProcessor implements SceneProcessor, Savable {
                     }
                 }
                 
+                boolean wantsBilinear = filter.isRequiresBilinear();
+                if (wantsBilinear) {
+                    tex.setMagFilter(Texture.MagFilter.Bilinear);
+                    tex.setMinFilter(Texture.MinFilter.BilinearNoMipMaps);
+                }
+
                 buff = outputBuffer;
                 if (i != lastFilterIndex) {
                     buff = filter.getRenderFrameBuffer();
@@ -293,6 +300,11 @@ public class FilterPostProcessor implements SceneProcessor, Savable {
                 }
                 renderProcessing(r, buff, mat);
                 filter.postFilter(r, buff);
+                
+                if (wantsBilinear) {
+                    tex.setMagFilter(Texture.MagFilter.Nearest);
+                    tex.setMinFilter(Texture.MinFilter.NearestNoMipMaps);
+                }
             }
         }
     }

jme3-effects/src/main/java/com/jme3/post/filters/FXAAFilter.java

@@ -70,6 +70,12 @@ public class FXAAFilter extends Filter {
         return material;
     }
     
+    @Override
+    protected boolean isRequiresBilinear() {
+        // FXAA wants the input texture to be filtered.
+        return true;
+    }
+
     public void setSpanMax(float spanMax) {
         this.spanMax = spanMax;
         if (material != null) {