Improve buffer reuse logic in UIBufferedComponent and subclasses

Author: Reco1I

src/com/reco1l/andengine/buffered/UIBufferedComponent.kt

@@ -13,10 +13,19 @@ import javax.microedition.khronos.opengles.GL10
  */
 abstract class UIBufferedComponent<T : IBuffer> : UIComponent() {
 
+    override var radius: Float
+        get() = super.radius
+        set(value) {
+            if (super.radius != value) {
+                super.radius = value
+                requestBufferUpdate()
+            }
+        }
+
     /**
      * The buffer itself.
      */
-    open var buffer: T? = null
+    var buffer: T? = null
         set(value) {
             if (field != value) {
                 field?.finalize()
@@ -29,11 +38,6 @@ abstract class UIBufferedComponent<T : IBuffer> : UIComponent() {
      */
     var allowBufferCache = true
 
-    /**
-     * Whether to allow the buffer to be updated dynamically.
-     */
-    var allowBufferDynamicUpdate = true
-
     /**
      * The blend information of the entity.
      */
@@ -70,7 +74,18 @@ abstract class UIBufferedComponent<T : IBuffer> : UIComponent() {
     protected abstract fun generateBufferCacheKey(): String
 
     /**
-     * Called when the buffer needs to be built.
+     * Determines if the current buffer can be reused instead of creating a new one.
+     *
+     * Override this method to implement custom buffer reuse logic based on buffer properties.
+     * Return `true` if the existing buffer is compatible and can be reused, `false` otherwise.
+     *
+     * @param buffer The current buffer to check for reusability
+     * @return `true` if the buffer can be reused, `false` if a new buffer should be created
+     */
+    protected open fun canReuseBuffer(buffer: T): Boolean = false
+
+    /**
+     * Called when a new buffer needs to be created.
      */
     protected abstract fun createBuffer(): T
 
@@ -96,7 +111,8 @@ abstract class UIBufferedComponent<T : IBuffer> : UIComponent() {
         requestBufferUpdate()
     }
 
-    override fun onManagedDraw(gl: GL10, camera: Camera) {
+    override fun onHandleInvalidations() {
+        super.onHandleInvalidations()
 
         // Buffer update is done after invalidations are handled so we can
         // refer the buffer in those invalidations.
@@ -105,34 +121,38 @@ abstract class UIBufferedComponent<T : IBuffer> : UIComponent() {
 
             val cacheKey = generateBufferCacheKey()
 
-            if (bufferCacheKey != cacheKey) {
-
-                if (allowBufferCache) {
-                    val newBuffer = UIEngine.current.resources.getOrStoreBuffer(cacheKey) { createBuffer() }
+            if (allowBufferCache) {
+                if (bufferCacheKey != cacheKey) {
+                    val newBuffer = UIEngine.current.resources.getOrStoreBuffer(cacheKey) {
+                        val currentBuffer = buffer
+                        if (currentBuffer != null && canReuseBuffer(currentBuffer)) {
+                            currentBuffer
+                        } else {
+                            createBuffer()
+                        }
+                    }
 
                     val oldBuffer = buffer
-                    if (oldBuffer != null) {
+                    if (oldBuffer != null && oldBuffer !== newBuffer) {
                         UIEngine.current.resources.unsubscribeFromBuffer(oldBuffer, this)
                     }
 
                     UIEngine.current.resources.subscribeToBuffer(newBuffer, this)
 
                     @Suppress("UNCHECKED_CAST")
                     buffer = newBuffer as T?
-                } else {
-                    if (!allowBufferDynamicUpdate || buffer == null) {
-                        buffer = createBuffer()
-                    }
+                    bufferCacheKey = cacheKey
+                }
+            } else {
+                val currentBuffer = buffer
+                if (currentBuffer == null || !canReuseBuffer(currentBuffer)) {
+                    buffer = createBuffer()
                 }
-
-                bufferCacheKey = cacheKey
             }
 
             onUpdateBuffer()
             buffer?.invalidateOnHardware()
         }
-
-        super.onManagedDraw(gl, camera)
     }
 
     override fun doDraw(gl: GL10, camera: Camera) {

src/com/reco1l/andengine/component/UIComponent.kt

@@ -401,7 +401,7 @@ abstract class UIComponent : Entity(0f, 0f), ITouchArea, IModifierChain {
     /**
      * The corner radius of this component.
      */
-    var radius = 0f
+    open var radius = 0f
         set(value) {
             if (field != value) {
                 field = value

src/com/reco1l/andengine/shape/UIBox.kt

@@ -32,16 +32,23 @@ open class UIBox : UIBufferedComponent<BoxVBO>() {
     var lineWidth = 1f
 
 
+    private val safeRadius
+        get() = radius.coerceAtMost(min(width, height) / 2f).coerceAtLeast(0f)
+
     private val segments
-        get() = if (radius > 0f) calculateArcResolution(radius, radius, 90f) else 0
+        get() = if (safeRadius > 0f) calculateArcResolution(safeRadius, safeRadius, 90f) else 0
 
 
     override fun createBuffer(): BoxVBO {
-        return BoxVBO(radius, segments, paintStyle)
+        return BoxVBO(segments, paintStyle)
+    }
+
+    override fun canReuseBuffer(buffer: BoxVBO): Boolean {
+        return buffer.segments == segments && buffer.paintStyle == paintStyle
     }
 
     override fun generateBufferCacheKey(): String {
-        return "BoxVBO@$width,$height,$radius,$segments,$paintStyle"
+        return "BoxVBO@$width,$height,$segments,$paintStyle"
     }
 
     override fun onUpdateBuffer() {
@@ -58,7 +65,6 @@ open class UIBox : UIBufferedComponent<BoxVBO>() {
 
 
     class BoxVBO(
-        val radius: Float,
         val segments: Int,
         val paintStyle: PaintStyle
     ) : VertexBuffer(
@@ -90,7 +96,7 @@ open class UIBox : UIBufferedComponent<BoxVBO>() {
                 putVertex(position++, width / 2f, height / 2f)
             }
 
-            val radius = radius.coerceAtMost(min(width, height) / 2f).coerceAtLeast(0f)
+            val radius = entity.radius.coerceAtMost(min(width, height) / 2f).coerceAtLeast(0f)
 
             // [1]
             position = addArc(position, radius, radius, -90f, 0f, radius, radius, segments)

src/com/reco1l/andengine/shape/UICircle.kt

@@ -55,6 +55,11 @@ open class UICircle : UIBufferedComponent<CircleVertexBuffer>() {
             }
         }
 
+
+    private val segments
+        get() = calculateArcResolution(width, height)
+
+
     /**
      * Sets the portion of the circle to be drawn starting from the start angle.
      *
@@ -72,12 +77,14 @@ open class UICircle : UIBufferedComponent<CircleVertexBuffer>() {
     }
 
     override fun createBuffer(): CircleVertexBuffer {
-        val segments = calculateArcResolution(width, height)
         return CircleVertexBuffer(segments, paintStyle)
     }
 
+    override fun canReuseBuffer(buffer: CircleVertexBuffer): Boolean {
+        return buffer.segments == segments && buffer.paintStyle == paintStyle
+    }
+
     override fun generateBufferCacheKey(): String {
-        val segments = calculateArcResolution(width, height)
         return "CircleVBO@$segments,$paintStyle"
     }
 
@@ -126,13 +133,5 @@ open class UICircle : UIBufferedComponent<CircleVertexBuffer>() {
             return max(3, segments)
         }
 
-        @Deprecated(
-            message = "Use calculateArcResolution instead",
-            replaceWith = ReplaceWith("calculateArcResolution(width, height, maximumAngle)")
-        )
-        fun approximateSegments(width: Float, height: Float, maximumAngle: Float = 360f): Int {
-            return calculateArcResolution(width, height, maximumAngle)
-        }
-
     }
 }

src/com/reco1l/andengine/shape/UILine.kt

@@ -44,6 +44,10 @@ class UILine : UIBufferedComponent<LineVertexBuffer>() {
         return LineVertexBuffer()
     }
 
+    override fun canReuseBuffer(buffer: LineVertexBuffer): Boolean {
+        return true
+    }
+
     override fun generateBufferCacheKey(): String {
         return "LineVBO@$fromPoint,$toPoint"
     }

src/com/reco1l/andengine/shape/UITriangle.kt

@@ -27,6 +27,10 @@ open class UITriangle : UIBufferedComponent<TriangleVBO>() {
         return TriangleVBO()
     }
 
+    override fun canReuseBuffer(buffer: TriangleVBO): Boolean {
+        return true
+    }
+
     override fun generateBufferCacheKey(): String {
         return "TriangleVBO@$width,$height"
     }

src/com/reco1l/andengine/sprite/UISprite.kt

@@ -122,6 +122,10 @@ open class UISprite(textureRegion: TextureRegion? = null) : UIBufferedComponent<
         return SpriteVBO()
     }
 
+    override fun canReuseBuffer(buffer: SpriteVBO): Boolean {
+        return true
+    }
+
     override fun generateBufferCacheKey(): String {
         return "SpriteVBO@$width,$height,$scaleType"
     }

src/com/reco1l/andengine/text/FontAwesomeIcon.kt

@@ -107,6 +107,10 @@ open class FontAwesomeIcon(icon: Int) : UIBufferedComponent<CompoundBuffer>() {
         return CompoundBuffer(IconTextureBuffer(), IconVertexBuffer())
     }
 
+    override fun canReuseBuffer(buffer: CompoundBuffer): Boolean {
+        return true
+    }
+
     override fun generateBufferCacheKey(): String {
         return "IconVBO@$iconSize,$iconVariant,$icon"
     }

src/com/reco1l/andengine/text/UIText.kt

@@ -296,6 +296,12 @@ open class UIText : UIBufferedComponent<CompoundBuffer>() {
         return UITextCompoundBuffer(capacity)
     }
 
+    override fun canReuseBuffer(buffer: CompoundBuffer): Boolean {
+        val capacity = nextPowerOfTwo(currentLength)
+        val vertexBuffer = buffer.getFirstOf<TextVertexBuffer>()
+        return vertexBuffer.vertexCount == capacity * VERTICES_PER_CHARACTER
+    }
+
     override fun generateBufferCacheKey(): String {
         val capacity = nextPowerOfTwo(currentLength)
         return "UITextVBO@$capacity,$fontSize,$fontFamily"

src/com/reco1l/andengine/text/UITextureText.kt

@@ -136,6 +136,10 @@ open class UITextureText(val characters: MutableMap<Char, TextureRegion>) : UIBu
         return TextureTextVertexBuffer()
     }
 
+    override fun canReuseBuffer(buffer: TextureTextVertexBuffer): Boolean {
+        return true
+    }
+
     override fun generateBufferCacheKey(): String {
         return "TextureTextVBO@${textureRegions.size}"
     }