Add movement component and system

cardinal/component/movement.go

@@ -0,0 +1,28 @@
+package component
+
+type Direction struct {
+	X int
+	Y int
+}
+
+var Directions = map[int]Direction{
+	0: {1, 0},  // right
+	1: {-1, 0}, // left
+	2: {0, -1}, // up
+	3: {0, 1},  // down
+}
+
+type Location struct {
+	X float32
+	Y float32
+}
+
+type Movement struct {
+	Direction Direction
+	Velocity  float32
+	Location  Location
+}
+
+func (Movement) Name() string {
+	return "Movement"
+}

cardinal/main.go

@@ -12,6 +12,15 @@ import (
 	"shantanu-starter-game/system"
 )
 
+/*
+ TODO:
+1. setup a new component and system for movement.
+2. should take in direction and have an onTick flow to lerp from current position to new position.
+3. whenever you get a new position, you should validate if its close enought to lerped position.
+4. if its close enough, you should update to that position continue lerping.
+5. if its not close enough, you should throw a an error. Client should handle this error and try again.
+*/
+
 func main() {
 	w, err := cardinal.NewWorld(cardinal.WithDisableSignatureVerification())
 	if err != nil {

cardinal/system/MovementSystem.go

@@ -0,0 +1,30 @@
+package system
+
+import (
+	"pkg.world.dev/world-engine/cardinal"
+	"pkg.world.dev/world-engine/cardinal/search/filter"
+	"pkg.world.dev/world-engine/cardinal/types"
+	comp "shantanu-starter-game/component"
+)
+
+// RegenSystem replenishes the player's HP at every tick.
+// This provides an example of a system that doesn't rely on a transaction to update a component.
+func MovementSystem(world cardinal.WorldContext) error {
+	return cardinal.NewSearch().Entity(
+		filter.Exact(filter.Component[comp.Player](), filter.Component[comp.Movement]())).
+		Each(world, func(id types.EntityID) bool {
+			movement, err := cardinal.GetComponent[comp.Movement](world, id)
+			if err != nil {
+				return true
+			}
+
+			// TODO: How to get delta time?
+			movement.Location.X += movement.Velocity * float32(movement.Direction.X)
+			movement.Location.Y += movement.Velocity * float32(movement.Direction.Y)
+
+			if err := cardinal.SetComponent[comp.Movement](world, id, movement); err != nil {
+				return true
+			}
+			return true
+		})
+}