added systems (not used yet, see TODO)

TODO.md

@@ -8,3 +8,9 @@
 - ignore comments in lvl files
 - add whitespace-mode flag in lvl files
 - check when sphere bounces from one end to the other endlessly w/o any solids in between. this is a game lock and equals game over
+
+SYSTEM Stuff:
+
+- initialize systems in NewLevel()
+- replace level.Update() with systems update
+- mv Draw() from level to systems

game/collectible_system.go

@@ -0,0 +1,54 @@
+package game
+
+import (
+	"fmt"
+	"image"
+	. "openquell/components"
+
+	"github.com/mlange-42/arche/ecs"
+	"github.com/mlange-42/arche/generic"
+)
+
+type CollectibleSystem struct {
+	World    *ecs.World
+	Selector *generic.Filter2[Position, Collectible]
+}
+
+func NewCollectibleSystem(world *ecs.World) *CollectibleSystem {
+	system := &CollectibleSystem{
+		Selector: generic.NewFilter2[Position, Collectible](),
+	}
+
+	return system
+}
+
+func (system *CollectibleSystem) CheckPlayerCollision(
+	playerposition *Position,
+	playervelocity *Velocity) (bool, image.Point) {
+
+	toRemove := []ecs.Entity{}
+	particle_pos := image.Point{}
+	var bumped bool
+
+	query := system.Selector.Query(system.World)
+
+	for query.Next() {
+		colposition, collectible := query.Get()
+
+		ok, _ := playerposition.Intersects(colposition, playervelocity)
+		if ok {
+			fmt.Printf("bumped into collectible %v\n", collectible)
+			toRemove = append(toRemove, query.Entity())
+			particle_pos.X = colposition.X
+			particle_pos.Y = colposition.Y
+			bumped = true
+		}
+	}
+
+	// remove collectible if collected
+	for _, entity := range toRemove {
+		system.World.RemoveEntity(entity)
+	}
+
+	return bumped, particle_pos
+}

game/levels.go

@@ -260,6 +260,17 @@ func (level *Level) DrawParticles(screen *ebiten.Image) {
 }
 
 func (level *Level) SetupGrid(game *Game) {
+	// generic variant does not work here:
+	// selector := generic.NewFilter1[components.Position]()
+	// level.World.Batch().RemoveEntities(selector)
+	// missing argument in conversion to generic.Filter1[components.Position]
+
+	// erase all entities of previous level, if any
+	posID := ecs.ComponentID[components.Position](level.World)
+	selector := ecs.All(posID)
+	level.World.Batch().RemoveEntities(selector)
+
+	// setup world
 	level.Grid = NewGrid(game, level.Cellsize, level.Mapslice)
 }
 

game/particle_system.go

@@ -0,0 +1,53 @@
+package game
+
+import (
+	"image"
+	. "openquell/components"
+
+	"github.com/mlange-42/arche/ecs"
+	"github.com/mlange-42/arche/generic"
+)
+
+type ParticleSystem struct {
+	World    *ecs.World
+	Selector *generic.Filter2[Position, Particle]
+	Cellsize int
+}
+
+func NewParticleSystem(world *ecs.World) *ParticleSystem {
+	system := &ParticleSystem{
+		Selector: generic.NewFilter2[Position, Particle](),
+	}
+
+	return system
+}
+
+func (system *ParticleSystem) Update(detonate bool, position *image.Point) {
+	// display debris after collecting
+	query := system.Selector.Query(system.World)
+
+	for query.Next() {
+		// we loop, but it's only one anyway
+		ptposition, particle := query.Get()
+
+		if detonate {
+			// particle appears
+			ptposition.Update(
+				position.X-(system.Cellsize/2),
+				position.Y-(system.Cellsize/2),
+				64,
+			)
+
+			particle.Index = 0 // start displaying the particle
+		} else {
+			switch {
+			// particle shows from earlier tick, animate
+			case particle.Index > -1 && particle.Index < len(particle.Particles)-1:
+				particle.Index++
+			default:
+				// last sprite reached, remove it
+				particle.Index = -1
+			}
+		}
+	}
+}

game/player_system.go

@@ -0,0 +1,83 @@
+package game
+
+import (
+	"fmt"
+	"image"
+	. "openquell/components"
+	. "openquell/config"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/mlange-42/arche/ecs"
+	"github.com/mlange-42/arche/generic"
+)
+
+type PlayerSystem struct {
+	World       *ecs.World
+	Grid        *Grid
+	Selector    *generic.Filter3[Position, Velocity, Player]
+	Particle    *ParticleSystem
+	Collectible *CollectibleSystem
+}
+
+func NewPlayerSystem(world *ecs.World) *PlayerSystem {
+
+	system := &PlayerSystem{
+		Selector: generic.NewFilter3[Position, Velocity, Player](),
+	}
+
+	return system
+}
+
+func (system PlayerSystem) Update() error {
+	query := system.Selector.Query(system.World)
+
+	var bumped bool
+	var particle_pos image.Point
+
+	for query.Next() {
+		playerposition, velocity, _ := query.Get()
+
+		if !velocity.Moving() {
+			switch {
+			case ebiten.IsKeyPressed(ebiten.KeyRight):
+				velocity.Change(East)
+			case ebiten.IsKeyPressed(ebiten.KeyLeft):
+				velocity.Change(West)
+			case ebiten.IsKeyPressed(ebiten.KeyDown):
+				velocity.Change(South)
+			case ebiten.IsKeyPressed(ebiten.KeyUp):
+				velocity.Change(North)
+				// other keys: <tab>: switch player, etc
+			}
+		}
+
+		if velocity.Moving() {
+			ok, newpos := system.Grid.BumpEdge(playerposition, velocity)
+			if ok {
+				fmt.Printf("falling off the edge, new pos: %v\n", newpos)
+				playerposition.Set(newpos)
+			} else {
+				ok, tilepos := system.Grid.GetSolidNeighborPosition(playerposition, velocity, true)
+				if ok {
+					intersects, newpos := tilepos.Intersects(playerposition, velocity)
+					if intersects {
+						fmt.Printf("collision detected. tile: %s\n", tilepos)
+						fmt.Printf("                  player: %s\n", playerposition)
+						fmt.Printf("                     new: %s\n", newpos)
+
+						playerposition.Set(newpos)
+						fmt.Printf("              player new: %s\n", playerposition)
+						velocity.Change(Stop)
+					}
+				}
+			}
+
+			bumped, particle_pos = system.Collectible.CheckPlayerCollision(playerposition, velocity)
+		}
+
+	}
+
+	system.Particle.Update(bumped, &particle_pos)
+
+	return nil
+}

systems/system.go

@@ -0,0 +1,8 @@
+package system
+
+import "github.com/hajimehoshi/ebiten/v2"
+
+type System interface {
+	Update() error
+	Draw(screen *ebiten.Image)
+}