add filter(PShader) function

core/src/processing/core/PApplet.java

@@ -10165,6 +10165,12 @@ public class PApplet extends Applet
   }
 
 
+  public void filter(Object shader) {
+    if (recorder != null) recorder.filter(shader);
+    g.filter(shader);
+  }
+
+
   public void bezierVertex(float x2, float y2,
                            float x3, float y3,
                            float x4, float y4) {

core/src/processing/core/PGraphics.java

@@ -1536,6 +1536,11 @@ public class PGraphics extends PImage implements PConstants {
   }
   
   
+  public void filter(Object shader) {
+    showMissingWarning("filter");
+  }
+  
+  
   //////////////////////////////////////////////////////////////
 
   // CURVE/BEZIER VERTEX HANDLING