basic gravity working through effects

[physics.git] / src / Entities / PhysicsEntity.cpp

#include "PhysicsEntity.h"
#include "../debug.h"

#include "../Vector2.h"
#include "../Effects/Effect.h"
#include "../Effects/Gravity.h"

/// ***** Public Class Methods *****
PhysicsEntity::PhysicsEntity(const Vector2& pos)
    : Entity(pos), force(0,0), mass(1), CoR(1)
{
    g = new Gravity();
}
PhysicsEntity::~PhysicsEntity()
{
    delete g;
}

void PhysicsEntity::update(float time_step)
{
    position = positionAt(time_step);
    velocity = velocityAt(time_step);

    force *= 0;
}

Vector2 PhysicsEntity::positionAt(float time_step) const
{
    Vector2 newPosition = position;
    Vector2 newVelocity = velocity;
    Vector2 newForce = force;

    newPosition += g->positionDelta(this, time_step);
    newVelocity += g->velocityDelta(this, time_step);
    newForce += g->forceDelta(this, time_step);

    return newForce/mass / 2 * time_step * time_step + newVelocity * time_step + newPosition;
}

Vector2 PhysicsEntity::velocityAt(float time_step) const
{
    Vector2 newForce = force;
    Vector2 newVelocity = velocity;

    newForce += g->forceDelta(this, time_step);
    newVelocity += g->velocityDelta(this, time_step);

    return newForce/mass / 2 * time_step + newVelocity;
}

void PhysicsEntity::applyForce(const Vector2& force)
{
    this->force += force;
}

void PhysicsEntity::applyImpulse(const Vector2& impluse)
{
    velocity += impluse;
}