Initial commit

internal/entity/entity.go

@@ -0,0 +1,109 @@
+package entity
+
+import (
+	"time"
+
+	"edgaru089.ml/go/gl01/internal/util"
+	"edgaru089.ml/go/gl01/internal/util/itype"
+	"edgaru089.ml/go/gl01/internal/world"
+)
+
+// EntityBehaviour describes the behaviour of a type of entity with the same Name.
+type EntityBehaviour interface {
+	// Name returns the type Name of the behaviour.
+	Name() string
+
+	// Hitbox gets the size of the hitbox of the entity.
+	//
+	// The hitbox is positioned with the position coordinates pointing to
+	// the center of the bottom of the box.
+	Hitbox(pos itype.Vec3d, dataset itype.Dataset) itype.Vec3d
+
+	// EyeHeight gets the height of the eye of the entity.
+	EyeHeight(pos itype.Vec3d, dataset itype.Dataset) float64
+
+	// Update is called on every frame.
+	// It should be used to update physics.
+	Update(pos itype.Vec3d, dataset itype.Dataset, world *world.World, deltaTime time.Duration)
+}
+
+var behaviour = make(map[string]EntityBehaviour)
+
+// RegisterEntityBehaviour registers behaviour with the name of b.Name().
+//
+// If the name is already taken, false is returned and nothing is done.
+// Otherwise, true is returned and the entity is registered.
+func RegisterEntityBehaviour(b EntityBehaviour) bool {
+	if _, ok := behaviour[b.Name()]; ok {
+		return false
+	}
+
+	behaviour[b.Name()] = b
+	return true
+}
+
+// Entity is a struct holding a Behaviour, a Position and a Speed.
+type Entity struct {
+	b          EntityBehaviour
+	pos, speed itype.Vec3d // pos has a origin of the **center of the bottom** of the hitbox
+	ds         itype.Dataset
+
+	name string // a shortcut to b.Name(), the typename
+
+	onGround bool
+	worldbox []itype.Boxd
+	hp       []itype.Vec3d
+}
+
+func NewEntity(typename string, pos itype.Vec3d) *Entity {
+	var b EntityBehaviour
+	var ok bool
+	if b, ok = behaviour[typename]; !ok {
+		return nil
+	}
+	return &Entity{
+		b:    b,
+		pos:  pos,
+		name: typename,
+	}
+}
+
+func (e *Entity) Position() itype.Vec3d {
+	return e.pos
+}
+
+func (e *Entity) SetPosition(pos itype.Vec3d) {
+	e.pos = pos
+}
+
+func (e *Entity) Speed() itype.Vec3d {
+	return e.speed
+}
+
+func (e *Entity) SetSpeed(speed itype.Vec3d) {
+	e.speed = speed
+}
+
+func (e *Entity) Hitbox() itype.Vec3d {
+	return e.b.Hitbox(e.pos, e.ds)
+}
+
+func (e *Entity) Accelerate(x, y, z float64) {
+	/*e.speed[0] += x
+	e.speed[1] += y
+	e.speed[2] += z*/
+	vec := itype.Vec3d{x, y, z}
+	e.speed = util.BunnyhopAccelerate(vec, e.speed, vec.Length(), 8)
+}
+
+func (e *Entity) OnGround() bool {
+	return e.onGround
+}
+
+func (e *Entity) EyeHeight() float64 {
+	return e.b.EyeHeight(e.pos, e.ds)
+}
+
+func (e *Entity) EyePosition() itype.Vec3d {
+	return e.pos.Addv(0, e.EyeHeight(), 0)
+}