wip: filter gui

inc/Renderer.h

@@ -1,4 +1,5 @@
 #pragma once
+#include "Filter.h"
 #include "ADSR.h"
 #include "Synth.h"
 #include "SynthGuiState.h"
@@ -19,7 +20,8 @@ class Renderer {
     void draw_signal(Synth& synth, SynthGuiState& synth_gui);
     void draw_adsr_panel(ADSR* adsr, ADSRGuiState& gui_adsr,
                          const Rectangle& panel_bounds, float panel_y_offset);
-
+    void draw_second_panel(Rectangle& bounds);
+    float draw_filter_panel(Filter* filter, FilterGuiState& gui_filter, const Rectangle& panel_bounds);
   public:
     Renderer(/* args */);
     ~Renderer();