Added start method called at the beginning of the frame for RFX

h3d/impl/RendererFX.hx

@@ -14,6 +14,7 @@ enum Step {
 
 interface RendererFX {
 	public var enabled : Bool;
+	public function start( r : h3d.scene.Renderer ) : Void;
 	public function begin( r : h3d.scene.Renderer, step : Step ) : Void;
 	public function end( r : h3d.scene.Renderer, step : Step ) : Void;
 	public function dispose() : Void;

h3d/scene/Renderer.hx

@@ -180,6 +180,12 @@ class Renderer extends hxd.impl.AnyProps {
 	public function start() {
 	}
 
+	public function startEffects() {
+		for ( e in effects )
+			if ( e.enabled )
+				e.start(this);
+	}
+
 	public function process( passes : Array<PassObjects> ) {
 		hasSetTarget = false;
 		for( p in allPasses )