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                 Msp::LinAl::Vector<float, 2> external_force;
  21
  22                 Msp::LinAl::Vector<float, 2> position;
  23                 Msp::LinAl::Vector<float, 2> velocity;
  24
  25                 unsigned collision_count;
  26                 Msp::LinAl::Vector<float, 2> position_adjust;
  27         };
  28
  29         struct Collision
  30         {
  31                 std::uint16_t body1 = 0;
  32                 std::uint16_t body2 = 0;
  33                 Msp::LinAl::Vector<float, 2> point;
  34                 float depth = 0.0f;
  35                 Msp::LinAl::Vector<float, 2> normal;
  36         };
  37
  38         Msp::Game::EventObserver observer;
  39         std::vector<SimulatedEntity> entities;
  40         unsigned fixture_count = 0;
  41         std::vector<Collision> collisions;
  42
  43 public:
  44         Physics(Msp::Game::Stage &);
  45
  46 private:
  47         void entity_added(const Msp::Game::Events::EntityCreated &);
  48
  49 public:
  50         void tick(Msp::Time::TimeDelta) override;
  51
  52 private:
  53         template<bool>
  54         void copy_in(SimulatedEntity &);
  55
  56         template<bool>
  57         void copy_out(SimulatedEntity &);
  58
  59         void step(float);
  60         void detect_collisions();
  61         void solve_collisions();
  62         void apply_impulses();
  63
  64         Collision &get_collision(unsigned, unsigned);
  65         void collide_circle_circle(unsigned, unsigned);
  66 };
  67
  68 #endif