examples/bassteroids/source/physics.h

   1 #ifndef PHYSICS_H_
   2 #define PHYSICS_H_
   3
   4 #include <msp/game/eventobserver.h>
   5 #include <msp/game/eventsource.h>
   6 #include <msp/game/events.h>
   7 #include <msp/game/handle.h>
   8 #include <msp/game/system.h>
   9 #include <msp/geometry/angle.h>
  10 #include <msp/linal/vector.h>
  11 #include "events.h"
  12
  13 class PhysicalEntity;
  14
  15 class Physics: public Msp::Game::System
  16 {
  17 public:
  18         using EventSource = Msp::Game::EventSource<Events::Collision>;
  19
  20 private:
  21         struct SimulatedEntity
  22         {
  23                 Msp::Game::Handle<PhysicalEntity> entity;
  24                 float inverse_mass = 1.0f;
  25                 float inverse_momi = 1.0f;
  26                 Msp::LinAl::Vector<float, 2> external_force;
  27                 float external_torque = 0.0f;
  28
  29                 Msp::LinAl::Vector<float, 2> position;
  30                 Msp::Geometry::Angle<float> rotation;
  31                 Msp::LinAl::Vector<float, 2> velocity;
  32                 Msp::Geometry::Angle<float> angular_velocity;
  33
  34                 unsigned collision_count;
  35                 Msp::LinAl::Vector<float, 2> position_adjust;
  36         };
  37
  38         struct Collision
  39         {
  40                 std::uint16_t body1 = 0;
  41                 std::uint16_t body2 = 0;
  42                 Msp::LinAl::Vector<float, 2> point;
  43                 float depth = 0.0f;
  44                 Msp::LinAl::Vector<float, 2> normal;
  45         };
  46
  47         EventSource event_source;
  48         Msp::Game::EventObserver observer;
  49         std::vector<SimulatedEntity> entities;
  50         unsigned fixture_count = 0;
  51         std::vector<Collision> collisions;
  52
  53 public:
  54         Physics(Msp::Game::Stage &);
  55
  56 private:
  57         void entity_added(const Msp::Game::Events::EntityCreated &);
  58
  59 public:
  60         void tick(Msp::Time::TimeDelta) override;
  61
  62 private:
  63         template<bool>
  64         void copy_in(SimulatedEntity &);
  65
  66         template<bool>
  67         void copy_out(SimulatedEntity &);
  68
  69         void step(float);
  70         void detect_collisions();
  71         void solve_collisions();
  72         void apply_impulses();
  73
  74         Collision &get_collision(unsigned, unsigned);
  75         void collide_circle_circle(unsigned, unsigned);
  76         void collide_circle_box(unsigned, unsigned);
  77 };
  78
  79 #endif