blob: 6869630de2c16973e519a40d2fcb53cb691f025c (
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
|
package forces
import (
"../structs"
"math"
)
// forces_acting calculates the force inbetween the two given stars s1 and s2
// The function return the force
func forceActing(s1 structs.Star, s2 structs.Star) structs.Force {
// Gravitational constant
var G = 6.674 * math.Pow(10, -11)
// Distance between the stars
var r21 = math.Sqrt(math.Pow(s2.C.X-s1.C.X, 2) + math.Pow(s2.C.Y-s1.C.Y, 2))
// Unit vector pointing from s1 to s2
rhat := structs.Force{s2.C.X - s1.C.X, s2.C.Y - s1.C.Y}
// Calculate how strong the star is affected
var F_scalar = G * (s1.Mass * s2.Mass) / math.Pow(math.Abs(r21), 2)
// Calculate the overall force by combining the scalar and the vector
var Fx = F_scalar * rhat.X
var Fy = F_scalar * rhat.Y
// Pack the forces in a force structur
F := structs.Force{Fx, Fy}
return F
}
// forces calculates the forces acting in between a given star and all the other stars in a given array.
func Forces(stars_arr []structs.Star, nr int) structs.Force {
var force structs.Force
// Iterate over all the stars in the stars_arr
for index := range stars_arr {
// If the current star is not the star itself
if index != nr {
// generate a new force and add it to the overall force of the star
fa := forceActing(stars_arr[nr], stars_arr[index])
stars_arr[nr].F.X += fa.X
stars_arr[nr].F.Y += fa.Y
force.X += fa.X
force.Y += fa.Y
}
}
return force
}
|