/
view.go
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/
view.go
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/*
* Copyright (c) 2020 Juan Medina.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package goecs
import (
"fmt"
"github.com/juan-medina/goecs/sparse"
"reflect"
)
const (
entitiesCapacity = 2000
entitiesGrow = entitiesCapacity / 4
)
// Iterator for view
type Iterator interface {
// Next returns next element
Next() Iterator
// Value returns the current item value
Value() *Entity
}
// View represent a set of Entity objects
type View struct {
entities sparse.Slice
}
// String get a string representation of a View
func (vw View) String() string {
str := ""
for it := vw.Iterator(); it != nil; it = it.Next() {
if str != "" {
str += ","
}
ent := it.Value()
str += ent.String()
}
return fmt.Sprintf("View{entities: [%v]}", str)
}
// AddEntity a Entity instance to a View given it components
func (vw *View) AddEntity(components ...interface{}) *Entity {
ent := NewEntity(components...)
vw.entities.Add(ent)
return ent
}
// Remove a Entity from a View
func (vw *View) Remove(ent *Entity) error {
return vw.entities.Remove(ent)
}
// Size of Entity in the View
func (vw View) Size() int {
return vw.entities.Size()
}
type viewIterator struct {
view *View
eit sparse.Iterator
filter []reflect.Type
}
func (vi *viewIterator) Next() Iterator {
for vi.eit = vi.eit.Next(); vi.eit != nil; vi.eit = vi.eit.Next() {
val := vi.Value()
if val.Contains(vi.filter...) {
return vi
}
}
return nil
}
func (vi *viewIterator) first() Iterator {
for it := vi.view.entities.Iterator(); it != nil; it = it.Next() {
val := it.Value().(*Entity)
if val.Contains(vi.filter...) {
vi.eit = it
return vi
}
}
return nil
}
func (vi *viewIterator) Value() *Entity {
return vi.eit.Value().(*Entity)
}
// Iterator return an view.Iterator for the given varg reflect.Type
func (vw *View) Iterator(rtypes ...reflect.Type) Iterator {
it := viewIterator{
view: vw,
eit: nil,
filter: rtypes,
}
return it.first()
}
// Clear removes all Entity from the view.View
func (vw *View) Clear() {
vw.entities.Clear()
}
// Sort the entities in place with a less function
func (vw *View) Sort(less func(a, b *Entity) bool) {
vw.entities.Sort(func(a interface{}, b interface{}) bool {
return less(a.(*Entity), b.(*Entity))
})
}
// NewView creates a new empty View
func NewView() *View {
return &View{
entities: sparse.NewSlice(entitiesCapacity, entitiesGrow),
}
}