fixing bug where the hitbox won't change when actor is rescaled, wip issue #34

src/net/torvald/spriteanimation/SpriteAnimation.kt

@@ -130,17 +130,19 @@ class SpriteAnimation(@Transient val parentActor: ActorWBMovable) {
             val region = textureRegion.get(currentFrame, currentRow)
             batch.color = colorFilter
 
+            val scale = parentActor.scale.toFloat()
+
             if (flipHorizontal && flipVertical) {
                 batch.draw(region,
-                        FastMath.floor(posX).toFloat() + (2f * parentActor.hitboxTranslateX * parentActor.scale.toFloat() + parentActor.hitbox.width.toFloat()),
+                        FastMath.floor(posX).toFloat() + (2f * parentActor.hitboxTranslateX * scale + parentActor.hitbox.width.toFloat()),
-                        FastMath.floor(posY).toFloat() + (2f * parentActor.hitboxTranslateY * parentActor.scale.toFloat() + parentActor.hitbox.height.toFloat()),
+                        FastMath.floor(posY).toFloat() + (2f * parentActor.hitboxTranslateY * scale + parentActor.hitbox.height.toFloat()),
                         -FastMath.floor(cellWidth * scale).toFloat(),
                         -FastMath.floor(cellHeight * scale).toFloat()
                 )
             }
             else if (flipHorizontal) {
                 batch.draw(region,
-                        FastMath.floor(posX).toFloat() + (2f * parentActor.hitboxTranslateX * parentActor.scale.toFloat() + parentActor.hitbox.width.toFloat()),
+                        FastMath.floor(posX).toFloat() + (2f * parentActor.hitboxTranslateX * scale + scale * parentActor.hitbox.width.toFloat()),
                         FastMath.floor(posY).toFloat(),
                         -FastMath.floor(cellWidth * scale).toFloat(),
                         FastMath.floor(cellHeight * scale).toFloat()
@@ -149,7 +151,7 @@ class SpriteAnimation(@Transient val parentActor: ActorWBMovable) {
             else if (flipVertical) {
                 batch.draw(region,
                         FastMath.floor(posX).toFloat(),
-                        FastMath.floor(posY).toFloat() + (2f * parentActor.hitboxTranslateY * parentActor.scale.toFloat() + parentActor.hitbox.height.toFloat()),
+                        FastMath.floor(posY).toFloat() + (2f * parentActor.hitboxTranslateY * scale + parentActor.hitbox.height.toFloat()),
                         FastMath.floor(cellWidth * scale).toFloat(),
                         -FastMath.floor(cellHeight * scale).toFloat()
                 )

src/net/torvald/terrarum/gameactors/ActorWBMovable.kt

@@ -132,15 +132,15 @@ open class ActorWBMovable(renderOrder: RenderOrder, val immobileBody: Boolean =
      * Physical properties.
      */
     /** Apparent scale. Use "avBaseScale" for base scale */
-    var scale: Double
+    val scale: Double
         inline get() = (actorValue.getAsDouble(AVKey.SCALE) ?: 1.0) *
                        (actorValue.getAsDouble(AVKey.SCALEBUFF) ?: 1.0)
-        set(value) {
+        /*set(value) {
             val scaleDelta = value - scale
             actorValue[AVKey.SCALE] = value / (actorValue.getAsDouble(AVKey.SCALEBUFF) ?: 1.0)
             // reposition
             translatePosition(-baseHitboxW * scaleDelta / 2, -baseHitboxH * scaleDelta)
-        }
+        }*/
     @Transient val MASS_LOWEST = 0.1 // Kilograms
     /** Apparent mass. Use "avBaseMass" for base mass */
     val mass: Double
@@ -298,6 +298,8 @@ open class ActorWBMovable(renderOrder: RenderOrder, val immobileBody: Boolean =
     }
 
     /**
+     * ONLY FOR INITIAL SETUP
+     *
      * @param w
      * @param h
      * @param tx positive: translate sprite to LEFT.
@@ -318,6 +320,8 @@ open class ActorWBMovable(renderOrder: RenderOrder, val immobileBody: Boolean =
 
 
     /**
+     * ONLY FOR INITIAL SETUP
+     *
      * Set hitbox position from bottom-center point
      * @param x
      * @param y
@@ -330,10 +334,6 @@ open class ActorWBMovable(renderOrder: RenderOrder, val immobileBody: Boolean =
                 baseHitboxH * scale)
     }
 
-    private fun translatePosition(dx: Double, dy: Double) {
-        hitbox.translate(dx, dy)
-    }
-
     // get() methods are moved to update(), too much stray object being created is definitely not good
     val centrePosVector: Vector2 = Vector2(0.0,0.0)
         //get() = Vector2(hitbox.centeredX, hitbox.centeredY)
@@ -363,6 +363,11 @@ open class ActorWBMovable(renderOrder: RenderOrder, val immobileBody: Boolean =
 
     override fun update(delta: Float) {
 
+        // re-scale hitbox
+        // it's just much better to poll them than use perfectly-timed setter because latter simply cannot exist
+        hitbox.canonicalResize(baseHitboxW * scale, baseHitboxH * scale)
+
+
         val oldHitbox = hitbox.clone()
 
         if (isUpdate && !flagDespawn) {

src/net/torvald/terrarum/gameactors/Hitbox.kt

@@ -33,9 +33,21 @@ class Hitbox (x1: Double, y1: Double, width: Double, height: Double, var suppres
         }
     }
 
-    override fun toString(): String {
+
-        return "[$hitboxStart - $hitboxEnd]"
+    val startX: Double
-    }
+        get() = hitboxStart.x
+    val startY: Double
+        get() = hitboxStart.y
+
+    val endX: Double
+        get() = hitboxStart.x + width
+    val endY: Double
+        get() = hitboxStart.y + height
+
+    val centeredX: Double
+        get() = hitboxStart.x + width * 0.5
+    val centeredY: Double
+        get() = hitboxStart.y + height * 0.5
 
     /**
      * @return bottom-centered point of hitbox.
@@ -49,11 +61,6 @@ class Hitbox (x1: Double, y1: Double, width: Double, height: Double, var suppres
     inline val canonicalY: Double
         get() = endY
 
-    val endX: Double
-        get() = hitboxStart.x + width
-    val endY: Double
-        get() = hitboxStart.y + height
-
     /**
      * Set to the point top left
      * @param x1
@@ -111,34 +118,31 @@ class Hitbox (x1: Double, y1: Double, width: Double, height: Double, var suppres
         return this
     }
 
+    /**
+     * For initial setup only. Use CanonicalResize for graceful resizing
+     */
     fun setDimension(w: Double, h: Double): Hitbox {
         width = w
         height = h
         return this
     }
 
+    fun canonicalResize(w: Double, h: Double): Hitbox {
+        // sx_1 + 0.5w_1 = sx_2 + 0.5w_2 // equals because the final point must not move. sx_1: old start-x, sx_2: new start-x which is what we want
+        // sx_2 = sx_1 + 0.5w_1 - 0.5w_2 // move variables to right-hand side to derive final value sx_2
+
+        hitboxStart.set(
+                startX + 0.5 * width - 0.5 * w,
+                startY + height - h
+        )
+        width = w
+        height = h
+        return this
+    }
+
     fun containsPoint(x: Double, y: Double) = (hitboxStart.x - x) in 0.0..width && (hitboxStart.y - y) in 0.0..height
     fun containsPoint(p: Point2d) = containsPoint(p.x, p.y)
 
-    /**
-     * Returns x value of start point
-     * @return top-left point startX
-     */
-    val startX: Double
-        get() = hitboxStart.x
-
-    /**
-     * Returns y value of start point
-     * @return top-left point startY
-     */
-    val startY: Double
-        get() = hitboxStart.y
-
-    val centeredX: Double
-        get() = hitboxStart.x + width * 0.5
-
-    val centeredY: Double
-        get() = hitboxStart.y + height * 0.5
 
     infix fun intersects(position: Point2d) =
             (position.x >= startX && position.x <= startX + width) &&
@@ -162,4 +166,8 @@ class Hitbox (x1: Double, y1: Double, width: Double, height: Double, var suppres
                this.width == other.width &&
                this.height == other.height
     }
+
+    override fun toString(): String {
+        return "[$hitboxStart - $hitboxEnd]"
+    }
 }

src/net/torvald/terrarum/modulebasegame/console/SetScale.kt

@@ -4,6 +4,7 @@ import net.torvald.terrarum.Terrarum
 import net.torvald.terrarum.console.ConsoleCommand
 import net.torvald.terrarum.console.Echo
 import net.torvald.terrarum.console.EchoError
+import net.torvald.terrarum.gameactors.AVKey
 import net.torvald.terrarum.modulebasegame.TerrarumIngame
 import net.torvald.terrarum.gameactors.ActorWBMovable
 
@@ -27,7 +28,8 @@ internal object SetScale : ConsoleCommand {
                     EchoError("Target is not ActorWBMovable")
                 }
                 else {
-                    target.scale = scale
+                    target.actorValue[AVKey.SCALE] = scale
+                    //target.scale = scale
                 }
             }
             catch (e: NumberFormatException) {

src/net/torvald/terrarum/modulebasegame/gameactors/DroppedItem.kt

@@ -2,6 +2,7 @@ package net.torvald.terrarum.modulebasegame.gameactors
 
 import com.badlogic.gdx.graphics.g2d.SpriteBatch
 import net.torvald.terrarum.blockproperties.BlockCodex
+import net.torvald.terrarum.gameactors.AVKey
 import net.torvald.terrarum.gameactors.ActorWBMovable
 import net.torvald.terrarum.gameitem.GameItem
 import net.torvald.terrarum.itemproperties.ItemCodex
@@ -22,7 +23,7 @@ open class DroppedItem(private val item: GameItem) : ActorWBMovable(RenderOrder.
         else
             ItemCodex[item.dynamicID]!!.mass
 
-        scale = ItemCodex[item.dynamicID]!!.scale
+        actorValue[AVKey.SCALE] = ItemCodex[item.dynamicID]!!.scale
     }
 
     override fun update(delta: Float) {

src/net/torvald/terrarum/modulebasegame/gameactors/PlayerBuilderTestSubject1.kt

@@ -44,6 +44,7 @@ object PlayerBuilderTestSubject1 {
         //p.actorValue[AVKey.LUMA] = 1.93
 
         p.actorValue[AVKey.AIRJUMPPOINT] = 0
+        p.actorValue[AVKey.SCALE] = 2.0
 
         return p
     }