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package structs
// Define a struct storing essential star information such as it's coordinate, velocity and mass
type Star2D struct {
C Vec2 // coordinates of the star
V Vec2 // velocity of the star
M float64 // mass of the star
}
// InsideOf is a method that tests if the star it is applied on is in or outside of the given
// BoundingBox. It returns true if the star is inside of the BoundingBox and false if it isn't.
func (s Star2D) InsideOf(boundary BoundingBox) bool {
// Test if the star is inside or outside of the bounding box.
// Abort testing if one of the conditions is not met
if s.C.X < boundary.center.X+boundary.width/2 {
if s.C.X > boundary.center.X-boundary.width/2 {
if s.C.Y < boundary.center.Y+boundary.width/2 {
if s.C.Y > boundary.center.Y-boundary.width/2 {
return true
} else {
return false
}
} else {
return false
}
} else {
return false
}
} else {
return false
}
}
// Quadrant returns a string indicating in which quadrant of the given quadtree the point the method
// is applied on is.
// This methods presumes that the point is inside of the boundingBox
func (s Star2D) Quadrant(starsQuadtree *Quadtree) string {
centerX := starsQuadtree.boundary.center.X
centerY := starsQuadtree.boundary.center.Y
// test if the point is left the the center or not
if s.C.X < centerX {
// Test if the point is above or below of the center
if s.C.Y > centerY {
return "northwest"
} else {
return "southwest"
}
// The point is right of the center
} else {
// Test if the point is above or below of the center
if s.C.Y > centerY {
return "northeast"
} else {
return "southeast"
}
}
}
// Return a copy of the star by returning a star struct with the same values.
func (s *Star2D) Copy() Star2D {
return Star2D{s.C.Copy(), s.V.Copy(), s.M}
}
// Accelerate the star with the acceleration a for the time t.
// This changes the velocity of the star.
func (s *Star2D) AccelerateVelocity(a Vec2, t float64) {
s.V = s.V.Add(a.Multiply(t))
}
// Move the star with it's velocity for the time t.
// This changes the Position of the star.
func (s *Star2D) Move(t float64) {
s.C = s.C.Add(s.V.Multiply(t))
}
// Accelerate and move the star with it's velocity and the acceleration a for the time t
// This changes the position and the velocity of the star.
func (s *Star2D) Accelerate(a Vec2, t float64) {
s.AccelerateVelocity(a, t)
s.Move(t)
}
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