add an overdraw buffer to allow for layered rendering

src/engine/render/text.c

@@ -81,6 +81,7 @@ static const uint8_t font[128][FONT_ROWS] = {
  */
 void
 put_char(
+    framebuffer_e framebuffer,
     char c,
     uint32_t x,
     uint32_t y,
@@ -107,6 +108,7 @@ put_char(
                     ? fg_color : bg_color;
 
             put_rect(
+                framebuffer,
                 x + col * size,
                 y + row * size,
                 size,
@@ -121,6 +123,7 @@ put_char(
 
 void
 put_string(
+    framebuffer_e framebuffer,
     const char *text,
     uint32_t x,
     uint32_t y,
@@ -137,7 +140,7 @@ put_string(
             x = start_x;
             y += (FONT_ROWS + line_spacing) * size;
         } else {
-            put_char(*text, x, y, size, fg_color, bg_color);
+            put_char(framebuffer, *text, x, y, size, fg_color, bg_color);
             x += (FONT_COLS + spacing) * size;
         }