less trivial C++ interop

Sources/CppBackend/ball.hpp

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <simd/simd.h>
+#include <vector>
+
+struct Ball {
+  using vec2f = simd::float2;
+
+private:
+  constexpr static float speed = 80.0f;
+  constexpr static float worldSize = 512.0f;
+
+  vec2f _position, _velocity;
+  float _size;
+
+public:
+  Ball(vec2f pos, float angle, float ballSize) noexcept;
+  virtual ~Ball() noexcept = default;
+
+  void update(float deltaTime) noexcept;
+
+  [[nodiscard]] constexpr const vec2f& position() const noexcept {
+    return _position;
+  }
+  [[nodiscard]] constexpr const vec2f& velocity() const noexcept {
+    return _velocity;
+  }
+  [[nodiscard]] constexpr const float size() const noexcept {
+    return _size;
+  }
+};
+
+
+struct BallWorld {
+  std::vector<Ball> balls;
+
+  void add(Ball::vec2f pos, float angle, float ballSize) noexcept;
+  void update(float deltaTime) noexcept;
+};