mirror of
https://github.com/Threnklyn/advent-of-code-go.git
synced 2026-06-06 04:08:27 +02:00
alexchao26
46 lines
1.4 KiB
Go
46 lines
1.4 KiB
Go
package trig
|
|
|
|
import "math"
|
|
|
|
/*
|
|
AngleOffVertical takes in two 2D points, it calculates the angle
|
|
between the line and a vertical line (straight up from origin)
|
|
NOTE: "up"/"top" and "down" are lexically flipped b/c of drawing a grid
|
|
where 0, 0 is the top left corner and higher numbers physically go DOWN
|
|
but lexically increase/go UP 🤦♂️
|
|
*/
|
|
func AngleOffVertical(startX, startY, endX, endY int) float64 {
|
|
rise := float64(endX) - float64(startX)
|
|
run := float64(endY) - float64(startY)
|
|
|
|
var angle float64
|
|
// basically a big if/elseif/else block
|
|
switch {
|
|
case run == 0 && rise < 0: // up
|
|
angle = 0
|
|
case run == 0 && rise > 0: // down
|
|
angle = 180
|
|
case rise == 0 && run < 0: // left
|
|
angle = 270
|
|
case rise == 0 && run > 0: // right
|
|
angle = 90
|
|
case rise < 0 && run > 0: // top right
|
|
angle = -1 * math.Atan(run/rise) * 180 / math.Pi
|
|
case rise > 0 && run > 0: // bottom right
|
|
angle = 90 + math.Atan(rise/run)*180/math.Pi
|
|
case rise > 0 && run < 0: // bottom left
|
|
angle = 180 + -1*math.Atan(run/rise)*180/math.Pi
|
|
case rise < 0 && run < 0: // top left
|
|
angle = 270 + math.Atan(rise/run)*180/math.Pi
|
|
}
|
|
|
|
return angle
|
|
}
|
|
|
|
// Distance calculates the distance between two sets of 2D coordinates via Pythagorean's theorem
|
|
func Distance(startX, startY, endX, endY int) float64 {
|
|
dx := startX - endX
|
|
dy := startY - endY
|
|
return math.Sqrt(float64(dx*dx) + float64(dy*dy))
|
|
}
|