Added a way to determine who is nearby.

Started EcoSim example.

examples/ecosim/bunny.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"math"
+	"math/rand"
+	"time"
+
+	"github.com/GaryBrownEEngr/scratch/models"
+)
+
+type bunny struct {
+	sim    models.Scratch
+	sprite models.Sprite
+	food   *models.NearMeInfo
+	x, y   float64
+	health float64
+
+	wanderX, wanderY float64
+
+	spawnCounter int
+}
+
+func Main_Bunny(sim models.Scratch, x, y float64) {
+
+	s := sim.AddSprite("")
+	s.Costume("Bunny")
+	s.SetType(BunnyType)
+
+	s.Pos(x, y)
+	s.Z(1)
+	s.XYScale(.2, .2)
+	s.Visible(true)
+	s.Opacity(100)
+
+	b := bunny{
+		sim:          sim,
+		sprite:       s,
+		x:            x,
+		y:            y,
+		health:       50,
+		spawnCounter: 200,
+	}
+	time.Sleep(time.Millisecond * time.Duration(rand.Intn(1000)))
+
+	b.main()
+}
+
+func (s *bunny) main() {
+	// MainSpriteLoop:
+	for {
+		time.Sleep(time.Millisecond * 20)
+		s.health -= .1
+
+		switch {
+		case s.health <= 0:
+			s.sprite.DeleteSprite()
+			return
+		case s.health < 75 && s.findFood():
+			s.feed()
+		case s.breed():
+			//
+		default:
+			s.wander()
+		}
+
+		s.sprite.Angle(s.health)
+	}
+}
+
+func (s *bunny) findFood() bool {
+
+	if s.food == nil {
+		aroundMe := s.sprite.WhoIsNearMe(100)
+		minDis := math.MaxFloat64
+		for i, o := range aroundMe {
+			if o.SpriteType == GrassType {
+				deltaX := o.X - s.x
+				deltaY := o.Y - s.y
+				dist := deltaX*deltaX + deltaY*deltaY
+				if dist < minDis {
+					minDis = dist
+					s.food = &aroundMe[i]
+				}
+			}
+		}
+	}
+
+	return s.food != nil
+}
+
+func (s *bunny) feed() {
+	if s.food == nil {
+		return
+	}
+
+	if s.food.SpriteType != GrassType {
+		return
+	}
+
+	deltaX := s.food.X - s.x
+	deltaY := s.food.Y - s.y
+	dist := math.Sqrt(deltaX*deltaX + deltaY*deltaY)
+	if dist < 5 {
+		foodStatus := s.sim.GetSpriteInfoByID(s.food.SpriteID)
+		if foodStatus.Deleted {
+			s.food = nil
+			return
+		}
+
+		s.health = min(100, s.health+25)
+		s.sim.SendMsg(s.food.SpriteID, GrassHasBeenEaten{})
+		s.food = nil
+		return
+	}
+
+	speed := 1.0
+	deltaX /= dist * speed
+	deltaY /= dist * speed
+	s.x += deltaX
+	s.y += deltaY
+	s.sprite.Pos(s.x, s.y)
+}
+
+func (s *bunny) breed() bool {
+	if s.health < 90 {
+		return false
+	}
+	s.spawnCounter -= 1
+	if s.spawnCounter <= 0 {
+		s.spawnCounter = 200
+		s.health = 25
+		go Main_Bunny(s.sim, s.x, s.y)
+		return true
+	}
+	return false
+}
+
+func (s *bunny) wander() {
+	s.wanderX += rand.NormFloat64() * .01
+	s.wanderY += rand.NormFloat64() * .01
+
+	s.wanderX = max(-.5, min(.5, s.wanderX))
+	s.wanderY = max(-.5, min(.5, s.wanderY))
+
+	s.x += s.wanderX
+	s.y += s.wanderY
+	s.sprite.Pos(s.x, s.y)
+}

examples/ecosim/grass.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"math"
+	"math/rand"
+	"time"
+
+	"github.com/GaryBrownEEngr/scratch/models"
+)
+
+type GrassHasBeenEaten struct{}
+
+func Main_Grass(sim models.Scratch, x, y float64) {
+	time.Sleep(time.Millisecond * time.Duration(rand.Intn(100)))
+	x = float64(int(x))
+	y = float64(int(y))
+
+	s := sim.AddSprite("")
+	s.Costume("Grass")
+	s.SetType(GrassType)
+
+	s.Pos(x, y)
+	s.Z(0)
+	s.XYScale(10, 10)
+	s.Visible(true)
+	s.Opacity(10)
+
+	health := 5.0
+	spawnCountDown := 30
+
+MainSpriteLoop:
+	for {
+		time.Sleep(time.Millisecond * 100)
+
+		msgs := s.GetMsgs()
+		for _, msg := range msgs {
+			switch msg.(type) {
+			case GrassHasBeenEaten:
+				health -= 50
+			}
+		}
+
+		if health <= 0 {
+			s.DeleteSprite()
+			return
+		}
+
+		health = min(100, health+1)
+		s.Opacity(health)
+		if health == 100 {
+			spawnCountDown -= 1
+			if spawnCountDown <= 0 {
+				spawnCountDown = 30
+				// spawn more grass
+				newX := x + (float64(rand.Intn(3))-1)*10
+				newY := y + (float64(rand.Intn(3))-1)*10
+
+				nearMe := sim.WhoIsNearMe(x, y, 20)
+				for _, o := range nearMe {
+					if o.SpriteType != GrassType {
+						continue
+					}
+					delta := math.Abs(o.X-newX) + math.Abs(o.Y-newY)
+					if delta < 1 {
+						// fmt.Printf("Found matching grass: %v\n", o)
+						continue MainSpriteLoop
+					}
+				}
+
+				go Main_Grass(sim, newX, newY)
+			}
+		} else {
+			spawnCountDown = 30
+		}
+	}
+}

examples/ecosim/main.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"image"
+	"image/color"
+
+	"github.com/GaryBrownEEngr/scratch"
+	"github.com/GaryBrownEEngr/scratch/models"
+	"github.com/GaryBrownEEngr/scratch/sprite"
+)
+
+var (
+	SkyBlue    color.RGBA = color.RGBA{0x87, 0xCE, 0xEB, 0xFF}
+	SandyBrown color.RGBA = color.RGBA{0xD2, 0xB4, 0x8C, 0xFF}
+	LawnGreen  color.RGBA = color.RGBA{0x7C, 0xFC, 0x00, 0xFF}
+)
+
+const (
+	UndefinedType int = iota
+	GrassType
+	BunnyType
+)
+
+func main() {
+	params := scratch.ScratchParams{Width: 1000, Height: 1000, ShowFPS: true}
+	scratch.Start(params, simStartFunc)
+}
+
+func simStartFunc(sim models.Scratch) {
+	// Set the background by making a single pixel image and scaling it be be the entire screen.
+	img := image.NewRGBA(image.Rect(0, 0, 1, 1))
+	img.Set(0, 0, SandyBrown)
+	sim.AddCostume(img, "Background")
+	s := sim.AddSprite("background")
+	s.Costume("Background")
+	s.Z(0)
+	s.Scale(1010)
+	s.Visible(true)
+
+	img = image.NewRGBA(image.Rect(0, 0, 1, 1))
+	img.Set(0, 0, LawnGreen)
+	sim.AddCostume(img, "Grass")
+	sim.AddCostume(sprite.DecodeCodedSprite(sprite.TurtleImage), "Bunny")
+
+	for x := 0; x < 100; x += 10 {
+		go Main_Grass(sim, float64(x), 0)
+	}
+
+	// go Main_Grass(sim, 0, 0)
+	// go Main_Grass(sim, 50, 0)
+
+	go Main_Bunny(sim, 10, 10)
+}