Added a small micro example of the problem with SFML's use of const on drawable virtual functions which shows the _real_ reason they did this is because of a poor design decision to make both Drawable and RenderTarget equally in charge of drawing the other. AKA the 'Deadly Embrace' design flaw.

meson.build

@@ -49,3 +49,7 @@ executable('rvo_test', [
   ],
   override_options: exe_defaults,
   dependencies: dependencies)
+
+executable('constness', 'sfml-const/constness.cpp',
+  override_options: exe_defaults,
+  dependencies: dependencies)

sfml-const/constness.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+#include "constness.hpp"
+
+using std::cout;
+
+void RenderTarget::draw(const Drawable& drawable) {
+  drawable.draw(*this);
+}
+
+void Shape::draw(const RenderTarget& target) const {
+  cout << "shape draw\n";
+}
+
+using std::cout;
+
+int main() {
+
+  RenderTarget target;
+  Shape shape;
+
+  target.draw(shape);
+
+  return 0;
+}

sfml-const/constness.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+class Drawable;
+
+class RenderTarget {
+  public:
+    void draw(const Drawable& drawable);
+};
+
+class Drawable {
+  public:
+    virtual void draw(const RenderTarget& target) const = 0;
+};
+
+class Shape : public Drawable {
+  public:
+  void draw(const RenderTarget& target) const override;
+};