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::Geometry::Angle<float> rotation;
  24                 Msp::LinAl::Vector<float, 2> velocity;
  25
  26                 unsigned collision_count;
  27                 Msp::LinAl::Vector<float, 2> position_adjust;
  28         };
  29
  30         struct Collision
  31         {
  32                 std::uint16_t body1 = 0;
  33                 std::uint16_t body2 = 0;
  34                 Msp::LinAl::Vector<float, 2> point;
  35                 float depth = 0.0f;
  36                 Msp::LinAl::Vector<float, 2> normal;
  37         };
  38
  39         Msp::Game::EventObserver observer;
  40         std::vector<SimulatedEntity> entities;
  41         unsigned fixture_count = 0;
  42         std::vector<Collision> collisions;
  43
  44 public:
  45         Physics(Msp::Game::Stage &);
  46
  47 private:
  48         void entity_added(const Msp::Game::Events::EntityCreated &);
  49
  50 public:
  51         void tick(Msp::Time::TimeDelta) override;
  52
  53 private:
  54         template<bool>
  55         void copy_in(SimulatedEntity &);
  56
  57         template<bool>
  58         void copy_out(SimulatedEntity &);
  59
  60         void step(float);
  61         void detect_collisions();
  62         void solve_collisions();
  63         void apply_impulses();
  64
  65         Collision &get_collision(unsigned, unsigned);
  66         void collide_circle_circle(unsigned, unsigned);
  67         void collide_circle_box(unsigned, unsigned);
  68 };
  69
  70 #endif