66 lines
1.5 KiB
Go
66 lines
1.5 KiB
Go
package geom
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import (
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"math"
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)
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// PointF32 is an X, Y coordinate pair (floating point, 32 bits).
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type PointF32 struct {
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X, Y float32
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}
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// ZeroPtF32 is initialized on (0, 0).
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var ZeroPtF32 = PointF32{X: 0, Y: 0}
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// PtF32 is a shorthand function to create a point.
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func PtF32(x, y float32) PointF32 {
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return PointF32{x, y}
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}
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// To64 transforms the point p into a PointF.
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func (p PointF32) To64() PointF {
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return PointF{float64(p.X), float64(p.Y)}
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}
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// Add adds q as a vector to p.
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func (p PointF32) Add(q PointF32) PointF32 {
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return PointF32{p.X + q.X, p.Y + q.Y}
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}
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// Sub subtracts q as a vector from p.
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func (p PointF32) Sub(q PointF32) PointF32 {
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return PointF32{p.X - q.X, p.Y - q.Y}
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}
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// AngleTo calculates the angle [0..2*Pi) from point p to point q.
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func (p PointF32) AngleTo(q PointF32) float32 {
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a := float32(math.Atan(float64((p.Y - q.Y) / (p.X - q.X))))
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if q.X < p.X {
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return a + math.Pi
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}
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if a < 0 {
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a += 2 * math.Pi
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}
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return a
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}
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// Distance calculates the distance between points p and q.
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func (p PointF32) Distance(q PointF32) float32 {
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return float32(math.Sqrt(float64(p.Distance2(q))))
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}
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// Distance2 calculates the squared distance between points p and q.
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func (p PointF32) Distance2(q PointF32) float32 {
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dx := q.X - p.X
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dy := q.Y - p.Y
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return dx*dx + dy*dy
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}
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// In tests if the point p is inside the rectangle r.
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func (p PointF32) In(r RectangleF32) bool {
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if p.X < r.Min.X || p.X >= r.Max.X || p.Y < r.Min.Y || p.Y >= r.Max.Y {
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return false
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}
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return true
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}
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