Rename geom to math

pkg/game/math.go

@@ -0,0 +1,114 @@
+package game
+
+import (
+	"fmt"
+	"math"
+	"strings"
+)
+
+// Vector desribes a 3D vector
+type Vector struct {
+	X int `json:"x"`
+	Y int `json:"y"`
+}
+
+// Add adds one vector to another
+func (v *Vector) Add(v2 Vector) {
+	v.X += v2.X
+	v.Y += v2.Y
+}
+
+// Added calculates a new vector
+func (v Vector) Added(v2 Vector) Vector {
+	v.Add(v2)
+	return v
+}
+
+// Negated returns a negated vector
+func (v Vector) Negated() Vector {
+	return Vector{-v.X, -v.Y}
+}
+
+// Length returns the length of the vector
+func (v Vector) Length() float64 {
+	return math.Sqrt(float64(v.X*v.X + v.Y*v.Y))
+}
+
+// Distance returns the distance between two vectors
+func (v Vector) Distance(v2 Vector) float64 {
+	// Negate the two vectors and calciate the length
+	return v.Added(v2.Negated()).Length()
+}
+
+// Multiplied returns the vector multiplied by an int
+func (v Vector) Multiplied(val int) Vector {
+	return Vector{v.X * val, v.Y * val}
+}
+
+// Direction describes a compass direction
+type Direction int
+
+const (
+	North Direction = iota
+	NorthEast
+	East
+	SouthEast
+	South
+	SouthWest
+	West
+	NorthWest
+)
+
+// DirectionString simply describes the strings associated with a direction
+type DirectionString struct {
+	Long  string
+	Short string
+}
+
+// DirectionStrings is the set of strings for each direction
+var DirectionStrings = []DirectionString{
+	{"North", "N"},
+	{"NorthEast", "NE"},
+	{"East", "E"},
+	{"SouthEast", "SE"},
+	{"South", "S"},
+	{"SouthWest", "SW"},
+	{"West", "W"},
+	{"NorthWest", "NW"},
+}
+
+// String converts a Direction to a String
+func (d Direction) String() string {
+	return DirectionStrings[d].Long
+}
+
+// ShortString converts a Direction to a short string version
+func (d Direction) ShortString() string {
+	return DirectionStrings[d].Short
+}
+
+// DirectionFromString gets the Direction from a string
+func DirectionFromString(s string) (Direction, error) {
+	for i, d := range DirectionStrings {
+		if strings.ToLower(d.Long) == strings.ToLower(s) || strings.ToLower(d.Short) == strings.ToLower(s) {
+			return Direction(i), nil
+		}
+	}
+	return -1, fmt.Errorf("Unknown direction: %s", s)
+}
+
+var DirectionVectors = []Vector{
+	{0, 1},  // N
+	{1, 1},  // NE
+	{1, 0},  // E
+	{1, -1}, // SE
+	{0, -1}, // S
+	{-1, 1}, // SW
+	{-1, 0}, // W
+	{-1, 1}, // NW
+}
+
+// Vector converts a Direction to a Vector
+func (d Direction) Vector() Vector {
+	return DirectionVectors[d]
+}