Implement BGSHOW/HIDE

SMILEBASIC/bg.d

@@ -22,6 +22,7 @@ class BG
     int width, height;
     int rendermax = 899;
     PetitComputer petitcom;
+    bool show;
     this(PetitComputer pc)
     {
         chip[] = BGChip(0);
@@ -31,9 +32,12 @@ class BG
         scalex = 1;
         scaley = 1;
         r = 0;
+        show = true;
     }
     void render(float disw, float dish)
     {
+        if (!show)
+            return;
         float aspect = disw / dish;
         disw /= 2;
         dish /= 2;

SMILEBASIC/builtinfunctions.d

@@ -1607,6 +1607,14 @@ class BuiltinFunction
     {
         return p.bgpage;
     }
+    static void BGSHOW(PetitComputer p, int layer)
+    {
+        p.getBG(layer).show = true;
+    }
+    static void BGHIDE(PetitComputer p, int layer)
+    {
+        p.getBG(layer).show = false;
+    }
     static void EFCON()
     {
     }