void Scene::step()
{
// This is the heart of the simulation.
checkCollisions();
// EULER
//applyG();
getImpulse();
integrateVelocities();
updatePositions();
clearStep();
// Increment time for next step, used in RK4.
t += dt;
}
void Convex::applyChanges(int index, sf::Vector2f* collisionNormal)
{
float radius = getRadius(index);
sf::Vector2f collisionPoint(getPoint(index).x - _massCenter.x,
getPoint(index).y - _massCenter.y);
_momentOfInertia = _mass * pow(radius, 2);
float impulse = getImpulse(&collisionPoint, collisionNormal);
_velocity.x += impulse / _mass * collisionNormal->x;
_velocity.y += impulse / _mass * collisionNormal->y;
_angularVelocity = _angularVelocity + impulse / _momentOfInertia * (collisionPoint.x * collisionNormal->y - collisionPoint.y * collisionNormal->x);
}
/*
Calculates the coordinates of the collision point
*/
void Convex::convexCollision(Convex* other, sf::RenderWindow* window)
{
sf::Vector2f collisionNormal;
float collisionX, collisionY;
float x1, x2, x3, x4, y1, y2, y3, y4;
if (hasCollided(other))
{
for (int i = 0; i < getPointCount(); i++)
{
//Retrieves the coordinates of the point i
x1 = this->getPoint(i).x;
y1 = this->getPoint(i).y;
//If the index 'i' equals the amount of points
//the other end of the line should be the starting point
if (i == getPointCount() - 1)
{
x2 = this->getPoint(0).x;
y2 = this->getPoint(0).y;
}
else
{
x2 = this->getPoint(i + 1).x;
y2 = this->getPoint(i + 1).y;
}
for (int j = 0; j < other->getPointCount(); j++)
{
x3 = other->getPoint(j).x;
y3 = other->getPoint(j).y;
//If the index 'j' equals the amount of points
//the other end of the line should be the starting point
if (i == getPointCount() - 1)
{
x4 = other->getPoint(0).x;
y4 = other->getPoint(0).y;
}
else
{
x4 = other->getPoint(i + 1).x;
y4 = other->getPoint(i + 1).y;
}
collisionX = vectorProduct(vectorProduct(x1, y1, x2, y2),
vectorProduct(x1, 1, x2, 1),
vectorProduct(x3, y3, x4, y4),
vectorProduct(x3, 1, x4, 1))
/
vectorProduct(vectorProduct(x1, 1, x2, 1),
vectorProduct(y1, 1, y2, 1),
vectorProduct(x3, 1, x4, 1),
vectorProduct(y3, 1, y4, 1));
collisionY = vectorProduct(vectorProduct(x1, y1, x2, y2),
vectorProduct(y1, 1, y2, 1),
vectorProduct(x3, y3, x4, y4),
vectorProduct(y3, 1, y4, 1))
/
vectorProduct(vectorProduct(x1, 1, x2, 1),
vectorProduct(y1, 1, y2, 1),
vectorProduct(x3, 1, x4, 1),
vectorProduct(y3, 1, y4, 1));
//Checking that the collision point is actually between the corners
//of the convexes
if (isBetween(collisionX, x1, x2) && isBetween(collisionX, x3, x4) &&
isBetween(collisionY, y1, y2) && isBetween(collisionY, y3, y4))
{
//If the collision point is between these points use them to calculate the
//collisionNormal's components
if (isBetween(collisionX, x1, x2) && isBetween(collisionY, y1, y2))
{
float x = x2 - x1;
float y = y2 - y1;
float length = sqrt(pow(x, 2) + pow(y, 2));
float unitX = x / length;
float unitY = y / length;
collisionNormal.x = -unitY;
collisionNormal.y = unitX;
float impulse = getImpulse(&sf::Vector2f(collisionX, collisionY), &collisionNormal, other, this);
applyChanges(&collisionNormal, impulse, &sf::Vector2f(collisionX, collisionY), other, this);
}
else
{
float x = x4 - x3;
float y = y4 - y3;
float length = sqrt(pow(x, 2) + pow(y, 2));
float unitX = x / length;
float unitY = y / length;
collisionNormal.x = -unitY;
collisionNormal.y = unitX;
float impulse = getImpulse(&sf::Vector2f(collisionX, collisionY), &collisionNormal, this, other);
applyChanges(&collisionNormal, impulse, &sf::Vector2f(collisionX, collisionY), this, other);
}
sf::CircleShape circle(5);
circle.setFillColor(sf::Color::Red);
circle.setPosition(collisionX, collisionY);
window->draw(circle);
}
}
}
}
}
