examples/bassteroids/source/physics.h

   1 #ifndef PHYSICS_H_
   2 #define PHYSICS_H_
   3
   4 #include <msp/game/eventobserver.h>
   5 #include <msp/game/events.h>
   6 #include <msp/game/handle.h>
   7 #include <msp/game/system.h>
   8 #include <msp/geometry/angle.h>
   9 #include <msp/linal/vector.h>
  10
  11 class PhysicalEntity;
  12
  13 class Physics: public Msp::Game::System
  14 {
  15 private:
  16         struct SimulatedEntity
  17         {
  18                 Msp::Game::Handle<PhysicalEntity> entity;
  19                 float inverse_mass = 1.0f;
  20                 float moment_of_inertia = 1.0f;
  21                 Msp::LinAl::Vector<float, 2> external_force;
  22
  23                 Msp::LinAl::Vector<float, 2> position;
  24                 Msp::Geometry::Angle<float> rotation;
  25                 Msp::LinAl::Vector<float, 2> velocity;
  26                 Msp::Geometry::Angle<float> angular_velocity;
  27
  28                 unsigned collision_count;
  29                 Msp::LinAl::Vector<float, 2> position_adjust;
  30         };
  31
  32         struct Collision
  33         {
  34                 std::uint16_t body1 = 0;
  35                 std::uint16_t body2 = 0;
  36                 Msp::LinAl::Vector<float, 2> point;
  37                 float depth = 0.0f;
  38                 Msp::LinAl::Vector<float, 2> normal;
  39         };
  40
  41         Msp::Game::EventObserver observer;
  42         std::vector<SimulatedEntity> entities;
  43         unsigned fixture_count = 0;
  44         std::vector<Collision> collisions;
  45
  46 public:
  47         Physics(Msp::Game::Stage &);
  48
  49 private:
  50         void entity_added(const Msp::Game::Events::EntityCreated &);
  51
  52 public:
  53         void tick(Msp::Time::TimeDelta) override;
  54
  55 private:
  56         template<bool>
  57         void copy_in(SimulatedEntity &);
  58
  59         template<bool>
  60         void copy_out(SimulatedEntity &);
  61
  62         void step(float);
  63         void detect_collisions();
  64         void solve_collisions();
  65         void apply_impulses();
  66
  67         Collision &get_collision(unsigned, unsigned);
  68         void collide_circle_circle(unsigned, unsigned);
  69         void collide_circle_box(unsigned, unsigned);
  70 };
  71
  72 #endif