Brought in screen manager, minor refactor.

elements/projectile.go

@@ -0,0 +1,34 @@
+package elements
+
+import (
+	"math"
+	"mover/gamedata"
+)
+
+type Projectile struct {
+	Pos      gamedata.Coordinates
+	Velocity float64
+	a        float64
+}
+
+func NewProjectile(origin gamedata.Coordinates, angle, velocity float64) *Projectile {
+	return &Projectile{
+		Velocity: velocity,
+		a:        angle,
+		Pos:      origin,
+	}
+}
+
+func (p *Projectile) Update() {
+
+	dx := p.Velocity * math.Cos(p.a)
+	dy := p.Velocity * math.Sin(p.a)
+
+	p.Pos.X += dx
+	p.Pos.Y += dy
+
+}
+
+func (p *Projectile) Draw() {
+
+}