blob: e120904ee5ead2b6c33fd8b0a0d24ecec09a00cc (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
package structs
// Definition of a quadtree and it's nodes recursively
type Quadtree struct {
Boundary BoundingBox `json:"boundary"` // Spatial outreach of the quadtree
CenterOfMass Vec2 `json:"CenterOfMass"` // Center of mass of the cell
TotalMass float64 `json:"totalMass"` // Total mass of the cell
Depth int `json:"depth"` // Depth of the cell in the quadtree
Star Star2D `json:"star"` // Star inside the cell
// NW, NE, SW, SE
Quadrants []*Quadtree `json:"Quadrants"` // List of quadtrees representing individual Quadrants
// Quadrants
//northWest *Quadtree
//northEast *Quadtree
//southWest *Quadtree
//southEast *Quadtree
}
// SetCenterOfMass is a setter method for quadtrees.
// It sets the CenterOfMass of the quadtree to the given value
func (q *Quadtree) SetCenterOfMass(centerOfMass Vec2) {
q.CenterOfMass = centerOfMass
}
// CalcCenterOfMass is a calculator method for quadtrees.
// It recursively walks through the quadtree and calculates it's Center of mass.
// The calculated Center of mass is then inserted into the CenterOfMass variable.
func (q *Quadtree) CalcCenterOfMass() (Vec2, float64) {
var totalMass float64 = 0
var x float64 = 0
var y float64 = 0
// If the Node is a leaf
if q.IsLeaf() == true {
// update the values needed to calculate the Center of mass
totalMass += q.Star.M
x += q.Star.C.X * q.Star.M
y += q.Star.C.X * q.Star.M
return Vec2{x, y}, totalMass
} else {
// Iterate over all the Quadrants
for _, element := range q.Quadrants {
// Calculate the Center of mass for each quadrant
centerOfMass, totalMass := element.CalcCenterOfMass()
// Update the overall CenterOfMass for the individual quadtree
q.CenterOfMass.X += centerOfMass.X
q.CenterOfMass.Y += centerOfMass.Y
q.TotalMass += totalMass
}
}
// Return the original CenterOfMass and totalMass
return q.CenterOfMass, q.TotalMass
}
// IsLeaf is a method for quadtrees returning true if the node is a leaf (has no children)
// or returning false if the node is nor a leaf (has children).
func (q *Quadtree) IsLeaf() bool {
for _, element := range q.Quadrants {
if element == nil {
return true
}
}
return false
}
// NewQuadtree generates a new root node.
func NewQuadtree(boundary BoundingBox) Quadtree {
return Quadtree{Boundary: boundary}
}
|
