Add the concept of commands to the world and executing them

pkg/game/command.go

@@ -0,0 +1,23 @@
+package game
+
+import "github.com/google/uuid"
+
+// A command is simply a function that acts on the a given instance in the world
+type Command func() error
+
+// CommandMove will move the instance in question
+func (w *World) CommandMove(id uuid.UUID, vec Vector) Command {
+	return func() error {
+		// Move the instance
+		_, err := w.MovePosition(id, vec)
+		return err
+	}
+}
+
+// CommandSpawn
+// TODO: Two spawn commands with the same id could trigger a fail later on, we should prevent that somehow
+func (w *World) CommandSpawn(id uuid.UUID) Command {
+	return func() error {
+		return w.Spawn(id)
+	}
+}

pkg/game/command_test.go

@@ -0,0 +1,50 @@
+package game
+
+import (
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCommand_Spawn(t *testing.T) {
+	world := NewWorld()
+	a := uuid.New()
+
+	spawnCommand := world.CommandSpawn(a)
+	assert.NoError(t, world.Execute(spawnCommand), "Failed to execute spawn command")
+
+	instance, ok := world.Instances[a]
+	assert.True(t, ok, "No new instance in world")
+	assert.Equal(t, a, instance.id, "New instance has incorrect id")
+}
+
+func TestCommand_Move(t *testing.T) {
+	world := NewWorld()
+	a := uuid.New()
+	assert.NoError(t, world.Spawn(a), "Failed to spawn")
+
+	pos := Vector{
+		X: 1.0,
+		Y: 2.0,
+		Z: 3.0,
+	}
+
+	err := world.SetPosition(a, pos)
+	assert.NoError(t, err, "Failed to set position for instance")
+
+	move := Vector{
+		X: 3.0,
+		Y: 2.0,
+		Z: 1.0,
+	}
+
+	// Try the move command
+	moveCommand := world.CommandMove(a, move)
+	assert.NoError(t, world.Execute(moveCommand), "Failed to execute move command")
+
+	newpos, err := world.GetPosition(a)
+	assert.NoError(t, err, "Failed to set position for instance")
+	pos.Add(move)
+	assert.Equal(t, pos, newpos, "Failed to correctly set position for instance")
+}

pkg/game/geom.go

@@ -1,6 +1,15 @@
 package game
 
-type Position struct {
-	X int `json:"x"`
-	Y int `json:"y"`
+// Vector desribes a 3D vector
+type Vector struct {
+	X float64 `json:"x"`
+	Y float64 `json:"y"`
+	Z float64 `json:"z"`
+}
+
+// Add adds one vector to another
+func (v *Vector) Add(v2 Vector) {
+	v.X += v2.X
+	v.Y += v2.Y
+	v.Z += v2.Z
 }

pkg/game/world.go

@@ -8,10 +8,8 @@ import (
 
 // World describes a self contained universe and everything in it
 type World struct {
+	// Instances is a map of all the instances in the game
 	Instances map[uuid.UUID]Instance `json:"instances"`
-
-	// dataPath is the location for the data to be stored
-	dataPath string
 }
 
 // Instance describes a single entity or instance of an entity in the world
@@ -20,7 +18,7 @@ type Instance struct {
 	id uuid.UUID
 
 	// pos represents where this instance is in the world
-	pos Position
+	pos Vector
 }
 
 const kWorldFileName = "rove-world.json"
@@ -32,9 +30,11 @@ func NewWorld() *World {
 	}
 }
 
-// Adds an instance to the game
-func (w *World) CreateInstance() uuid.UUID {
-	id := uuid.New()
+// Spawn adds an instance to the game
+func (w *World) Spawn(id uuid.UUID) error {
+	if _, ok := w.Instances[id]; ok {
+		return fmt.Errorf("instance with id %s already exists in world", id)
+	}
 
 	// Initialise the instance
 	instance := Instance{
@@ -44,7 +44,7 @@ func (w *World) CreateInstance() uuid.UUID {
 	// Append the instance to the list
 	w.Instances[id] = instance
 
-	return id
+	return nil
 }
 
 // Removes an instance from the game
@@ -58,10 +58,42 @@ func (w *World) DestroyInstance(id uuid.UUID) error {
 }
 
 // GetPosition returns the position of a given instance
-func (w World) GetPosition(id uuid.UUID) (Position, error) {
+func (w World) GetPosition(id uuid.UUID) (Vector, error) {
 	if i, ok := w.Instances[id]; ok {
 		return i.pos, nil
 	} else {
-		return Position{}, fmt.Errorf("no instance matching id")
+		return Vector{}, fmt.Errorf("no instance matching id")
 	}
 }
+
+// SetPosition sets an instances position
+func (w *World) SetPosition(id uuid.UUID, pos Vector) error {
+	if i, ok := w.Instances[id]; ok {
+		i.pos = pos
+		w.Instances[id] = i
+		return nil
+	} else {
+		return fmt.Errorf("no instance matching id")
+	}
+}
+
+// SetPosition sets an instances position
+func (w *World) MovePosition(id uuid.UUID, vec Vector) (Vector, error) {
+	if i, ok := w.Instances[id]; ok {
+		i.pos.Add(vec)
+		w.Instances[id] = i
+		return i.pos, nil
+	} else {
+		return Vector{}, fmt.Errorf("no instance matching id")
+	}
+}
+
+// Execute will run the commands given
+func (w *World) Execute(commands ...Command) error {
+	for _, c := range commands {
+		if err := c(); err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/game/world_test.go

@@ -3,6 +3,7 @@ package game
 import (
 	"testing"
 
+	"github.com/google/uuid"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -16,8 +17,10 @@ func TestNewWorld(t *testing.T) {
 
 func TestWorld_CreateInstance(t *testing.T) {
 	world := NewWorld()
-	a := world.CreateInstance()
-	b := world.CreateInstance()
+	a := uuid.New()
+	b := uuid.New()
+	assert.NoError(t, world.Spawn(a), "Failed to spawn")
+	assert.NoError(t, world.Spawn(b), "Failed to spawn")
 
 	// Basic duplicate check
 	if a == b {
@@ -29,8 +32,10 @@ func TestWorld_CreateInstance(t *testing.T) {
 
 func TestWorld_DestroyInstance(t *testing.T) {
 	world := NewWorld()
-	a := world.CreateInstance()
-	b := world.CreateInstance()
+	a := uuid.New()
+	b := uuid.New()
+	assert.NoError(t, world.Spawn(a), "Failed to spawn")
+	assert.NoError(t, world.Spawn(b), "Failed to spawn")
 
 	err := world.DestroyInstance(a)
 	assert.NoError(t, err, "Error returned from instance destroy")
@@ -42,3 +47,27 @@ func TestWorld_DestroyInstance(t *testing.T) {
 		t.Error("Remaining instance is incorrect")
 	}
 }
+
+func TestWorld_GetSetMovePosition(t *testing.T) {
+	world := NewWorld()
+	a := uuid.New()
+	assert.NoError(t, world.Spawn(a), "Failed to spawn")
+
+	pos := Vector{
+		X: 1.0,
+		Y: 2.0,
+		Z: 3.0,
+	}
+
+	err := world.SetPosition(a, pos)
+	assert.NoError(t, err, "Failed to set position for instance")
+
+	newpos, err := world.GetPosition(a)
+	assert.NoError(t, err, "Failed to set position for instance")
+	assert.Equal(t, pos, newpos, "Failed to correctly set position for instance")
+
+	newpos, err = world.MovePosition(a, pos)
+	assert.NoError(t, err, "Failed to set position for instance")
+	pos.Add(pos)
+	assert.Equal(t, pos, newpos, "Failed to correctly move position for instance")
+}

pkg/server/router.go

@@ -155,7 +155,7 @@ type SpawnData struct {
 type SpawnResponse struct {
 	BasicResponse
 
-	Position game.Position `json:"position"`
+	Position game.Vector `json:"position"`
 }
 
 // HandleSpawn will spawn the player entity for the associated account
@@ -192,7 +192,8 @@ func (s *Server) HandleSpawn(w http.ResponseWriter, r *http.Request) {
 		fmt.Printf("\tspawn data: %v\n", data)
 
 		// Create a new instance
-		inst := s.world.CreateInstance()
+		inst := uuid.New()
+		s.world.Spawn(inst)
 		if pos, err := s.world.GetPosition(inst); err != nil {
 			response.Error = fmt.Sprint("No position found for created instance")