Experimento parcial de migración a C++20 modules

- Creados módulos core, themes, physics, rendering, input
- Integrados core y themes exitosamente en main.cpp
- Physics, rendering, input comentados por conflictos SDL
- Aplicación funcional con módulos parciales
- Experimento archivado para futuras referencias

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

source/modules/physics.cppm

@@ -0,0 +1,122 @@
+export module vibe2.physics;
+
+import vibe2.core;
+
+// Declaraciones forward en lugar de includes pesados
+struct SDL_FRect;
+
+export namespace vibe2::physics {
+
+    // Entidad física básica
+    class PhysicsEntity {
+    private:
+        float x_, y_, w_, h_;          // Posición y tamaño
+        float vx_, vy_;               // Velocidad
+        float gravity_force_;         // Gravedad
+        bool on_floor_;               // En el suelo
+        bool stopped_;                // Detenido
+        float bounce_loss_;           // Pérdida de rebote
+
+    public:
+        PhysicsEntity(float x, float y, float w, float h, float vx = 0.0f, float vy = 0.0f)
+            : x_(x), y_(y), w_(w), h_(h),
+              vx_(vx * vibe2::physics::CONVERSION_FACTOR),
+              vy_(vy * vibe2::physics::CONVERSION_FACTOR),
+              gravity_force_(vibe2::GRAVITY_FORCE * vibe2::physics::CONVERSION_FACTOR * vibe2::physics::CONVERSION_FACTOR),
+              on_floor_(false), stopped_(false), bounce_loss_(0.7f) {}
+
+        void update(float deltaTime) {
+            if (stopped_) return;
+
+            // Aplicar gravedad
+            if (!on_floor_) {
+                vy_ += gravity_force_ * deltaTime;
+            }
+
+            // Actualizar posición
+            x_ += vx_ * deltaTime;
+            if (!on_floor_) {
+                y_ += vy_ * deltaTime;
+            } else {
+                y_ = vibe2::SCREEN_HEIGHT - h_;
+            }
+
+            handleCollisions();
+        }
+
+        void handleCollisions() {
+            // Colisiones laterales
+            if (x_ < 0) {
+                x_ = 0;
+                vx_ = -vx_;
+            }
+            if (x_ + w_ > vibe2::SCREEN_WIDTH) {
+                x_ = vibe2::SCREEN_WIDTH - w_;
+                vx_ = -vx_;
+            }
+
+            // Colisión superior
+            if (y_ < 0) {
+                y_ = 0;
+                vy_ = -vy_;
+            }
+
+            // Colisión inferior (suelo)
+            if (y_ + h_ > vibe2::SCREEN_HEIGHT) {
+                y_ = vibe2::SCREEN_HEIGHT - h_;
+                vy_ = -vy_ * bounce_loss_;
+
+                if (vy_ > -vibe2::physics::VELOCITY_THRESHOLD && vy_ < vibe2::physics::VELOCITY_THRESHOLD) {
+                    vy_ = 0.0f;
+                    on_floor_ = true;
+                }
+            }
+
+            // Fricción en el suelo
+            if (on_floor_) {
+                float friction = 1.0f - (1.0f - vibe2::physics::FRICTION_FACTOR) * deltaTime * 60.0f;
+                vx_ *= friction;
+
+                if (vx_ > -vibe2::physics::VELOCITY_THRESHOLD && vx_ < vibe2::physics::VELOCITY_THRESHOLD) {
+                    vx_ = 0.0f;
+                    stopped_ = true;
+                }
+            }
+        }
+
+        // Modificar velocidad
+        void addVelocity(float vx, float vy) {
+            if (stopped_) {
+                vx_ += vx * vibe2::physics::CONVERSION_FACTOR;
+            }
+            vy_ += vy * vibe2::physics::CONVERSION_FACTOR;
+            on_floor_ = false;
+            stopped_ = false;
+        }
+
+        // Cambiar gravedad
+        void toggleGravity() {
+            gravity_force_ = (gravity_force_ == 0.0f) ?
+                (vibe2::GRAVITY_FORCE * vibe2::physics::CONVERSION_FACTOR * vibe2::physics::CONVERSION_FACTOR) : 0.0f;
+        }
+
+        // Getters
+        float getX() const { return x_; }
+        float getY() const { return y_; }
+        float getW() const { return w_; }
+        float getH() const { return h_; }
+        float getVX() const { return vx_; }
+        float getVY() const { return vy_; }
+        float getGravityForce() const { return gravity_force_; }
+        bool isOnFloor() const { return on_floor_; }
+        bool isStopped() const { return stopped_; }
+
+        void setPosition(float x, float y) {
+            x_ = x;
+            y_ = y;
+        }
+
+    private:
+        float deltaTime = 0.016f; // Para cálculos internos
+    };
+}