Implement rover radar and use and test it

pkg/game/world.go

@@ -133,11 +133,17 @@ type RadarDescription struct {
 
 // RadarFromRover can be used to query what a rover can currently see
 func (w World) RadarFromRover(id uuid.UUID) (RadarDescription, error) {
-	if _, ok := w.Rovers[id]; ok {
+	if r1, ok := w.Rovers[id]; ok {
+		var desc RadarDescription
 
-		// TODO: Gather nearby rovers within the range
+		// Gather nearby rovers within the range
+		for _, r2 := range w.Rovers {
+			if r1.Id != r2.Id && r1.Pos.Distance(r2.Pos) < r1.Attributes.Range {
+				desc.Rovers = append(desc.Rovers, r2.Pos)
+			}
+		}
 
-		return RadarDescription{}, nil
+		return desc, nil
 	} else {
 		return RadarDescription{}, fmt.Errorf("no rover matching id")
 	}

pkg/game/world_test.go

@@ -78,3 +78,25 @@ func TestWorld_GetSetMovePosition(t *testing.T) {
 	pos.Add(Vector{0, attribs.Speed * float64(duration)}) // We should have move one unit of the speed north
 	assert.Equal(t, pos, newpos, "Failed to correctly move position for rover")
 }
+
+func TestWorld_RadarFromRover(t *testing.T) {
+	world := NewWorld()
+	a := world.SpawnRover()
+	b := world.SpawnRover()
+	c := world.SpawnRover()
+
+	// Get a's attributes
+	attrib, err := world.RoverAttributes(a)
+	assert.NoError(t, err, "Failed to get rover attribs")
+
+	// Warp the rovers so a can see b but not c
+	assert.NoError(t, world.WarpRover(a, Vector{0, 0}), "Failed to warp rover")
+	assert.NoError(t, world.WarpRover(b, Vector{attrib.Range - 1, 0}), "Failed to warp rover")
+	assert.NoError(t, world.WarpRover(c, Vector{attrib.Range + 1, 0}), "Failed to warp rover")
+
+	radar, err := world.RadarFromRover(a)
+	assert.NoError(t, err, "Failed to get radar from rover")
+	assert.Equal(t, 1, len(radar.Rovers), "Radar returned wrong number of rovers")
+	assert.Equal(t, Vector{attrib.Range - 1, 0}, radar.Rovers[0], "Rover on radar in wrong position")
+
+}