start on physics

1 files changed, 78 insertions, 0 deletions

diff --git a/physics.hpp b/physics.hpp
new file mode 100644
index 0000000..6e6b259
--- /dev/null
+++ b/physics.hpp
@@ -0,0 +1,78 @@
+#ifndef physics_hpp
+#define physics_hpp
+
+#include "asset.hpp"
+#include "maths.hpp"
+
+#include <tuple>
+
+struct Arena;
+struct Line_Renderer;
+struct World;
+
+struct Manifold {
+	static constexpr int max_contacts = 16;
+	v3f contacts[max_contacts];
+	int contact_count;
+	v3f normal;
+};
+
+struct Rigidbody;
+struct Int_Collider {
+	Rigidbody* rb;
+	Int_Collider* next;
+	int vert_count;
+	int face_count;
+	v3f* verts;
+	v3f* faces;
+
+	bool collide(const Int_Collider& other) const;
+};
+
+struct Collider : Asset {
+	struct Face {
+		v3f normal;
+		int vert_count;
+		uint16_t* verts;
+	};
+	int face_count;
+	int vert_count;
+	Face* faces;
+	v3f* verts;
+	m3f moment;
+
+	void debug_render(
+		Line_Renderer& lr,
+		const m4f& t,
+		const v3f& c
+	);
+	Int_Collider* transform(const m4f& m, Arena* a) const;
+};
+
+struct Rigidbody {
+	v3f prev_pos, pos;
+	v3f vel, avel;
+	v3f force;
+	v3f torque;
+	v4f prev_rot, rot;
+	float inv_mass;
+	Collider* col;
+	int colliding;
+
+	void init(Collider* c, const v3f& p, const v4f& r, float mass);
+	void set_pos(const v3f& p);
+	void set_rot(const v4f& r);
+	void set_mass(float m);
+	void add_force(const v3f& f);
+	void add_force(const v3f& f, const v3f& p);
+	void add_impulse(const v3f& f);
+	void add_impulse(const v3f& f, const v3f& p);
+	void add_torque(const v3f& t);
+};
+
+Collider* make_box(Arena* a, const v3f& size);
+
+void physics_update(World& w, Arena* a, float ts);
+void physics_debug(World& w, Line_Renderer& lr);
+
+#endif