sprite.Turn(ti *spx.TurningInfo)

sprite.go

@@ -699,6 +699,7 @@ func (p *Sprite) Heading() float64 {
 //   Turn(degree)
 //   Turn(spx.Left)
 //   Turn(spx.Right)
+//   Turn(ti *spx.TurningInfo)
 func (p *Sprite) Turn(val interface{}) {
 	if debugInstr {
 		log.Println("Turn", p.name, val)
@@ -711,6 +712,9 @@ func (p *Sprite) Turn(val interface{}) {
 		delta = float64(v)
 	case float64:
 		delta = v
+	case *TurningInfo:
+		p.doTurnTogether(v) // don't animate
+		return
 	default:
 		panic("Turn: unexpected input")
 	}
@@ -757,6 +761,18 @@ func (p *Sprite) setDirection(dir float64, change bool) {
 	p.direction = normalizeDirection(dir)
 }
 
+func (p *Sprite) doTurnTogether(ti *TurningInfo) {
+	/*
+		x’ = x0 + cos * (x-x0) - sin * (y-y0)
+		y’ = y0 + sin * (x-x0) + cos * (y-y0)
+	*/
+	x0, y0 := ti.Obj.x, ti.Obj.y
+	dir := ti.Dir()
+	sin, cos := math.Sincos(dir * (math.Pi / 180))
+	p.x, p.y = x0+cos*(p.x-x0)+sin*(p.y-y0), y0-sin*(p.x-x0)+cos*(p.y-y0)
+	p.direction = normalizeDirection(p.direction + dir)
+}
+
 // -----------------------------------------------------------------------------
 
 func (p *Sprite) Size() float64 {

test/TurnTogether/Banana.spx

@@ -0,0 +1,3 @@
+Monkey.onTurning ti => {
+	turn ti
+}

test/TurnTogether/Banana2.spx

@@ -0,0 +1,3 @@
+Monkey.onTurning ti => {
+	turn ti.dir
+}

test/TurnTogether/Monkey.spx

@@ -0,0 +1,7 @@
+onKey KeyUp, => {
+	turn -30
+}
+
+onKey KeyDown, => {
+	turn 30
+}

test/TurnTogether/index.gmx

@@ -0,0 +1,7 @@
+var (
+	Banana  Banana
+	Banana2 Banana2
+	Monkey  Monkey
+)
+
+run "res", {Title: "Turn Together (by Go+)"}

test/TurnTogether/res/index.json

@@ -0,0 +1,32 @@
+{
+  "costumes": [
+    {
+      "bitmapResolution": 1,
+      "name": "backdrop1",
+      "path": "../../res/lake.jpg",
+      "x": 240,
+      "y": 180
+    }
+  ],
+  "currentCostumeIndex": 0,
+  "zorder": [
+    {
+      "type": "sprite",
+      "target": "Banana",
+      "x": -100,
+      "y": -21
+    },
+    {
+      "type": "sprite",
+      "target": "Banana2",
+      "x": 80,
+      "y": -81
+    },
+    {
+      "type": "sprite",
+      "target": "Monkey",
+      "x": 0,
+      "y": 50
+    }
+  ]
+}

test/TurnTogether/res/sprites/Banana/index.json

@@ -0,0 +1,16 @@
+{
+  "costumeSet": {
+    "bitmapResolution": 1,
+    "faceRight": 180,
+    "path": "../../../../res/banana.png",
+    "nx": 58
+  },
+  "currentCostumeIndex": 0,
+  "heading": 90,
+  "isDraggable": false,
+  "rotationStyle": "normal",
+  "size": 1,
+  "visible": true,
+  "x": -100,
+  "y": -21
+}

test/TurnTogether/res/sprites/Banana2/index.json

@@ -0,0 +1,16 @@
+{
+  "costumeSet": {
+    "bitmapResolution": 1,
+    "faceRight": 180,
+    "path": "../../../../res/banana.png",
+    "nx": 58
+  },
+  "currentCostumeIndex": 0,
+  "heading": 90,
+  "isDraggable": false,
+  "rotationStyle": "normal",
+  "size": 1,
+  "visible": true,
+  "x": -100,
+  "y": -21
+}

test/TurnTogether/res/sprites/Monkey/index.json

@@ -0,0 +1,16 @@
+{
+  "costumeSet": {
+    "bitmapResolution": 1,
+    "faceRight": 180,
+    "path": "../../../../res/monkey.png",
+    "nx": 96
+  },
+  "currentCostumeIndex": 0,
+  "heading": 90,
+  "isDraggable": false,
+  "rotationStyle": "normal",
+  "size": 1,
+  "visible": true,
+  "x": 100,
+  "y": 50
+}