From 9add30e5824fda220cae6b6a9b8e53344a9d3512 Mon Sep 17 00:00:00 2001
From: huangdarwin <huangdarwin@google.com>
Date: Wed, 29 Nov 2023 04:27:22 -0800
Subject: [PATCH] Effect: Use Bitmap generation ID to detect changes.

This is much simpler than using protected methods that signal updates in
bitmaps.

PiperOrigin-RevId: 586295312
---
 .../androidx/media3/effect/BitmapOverlay.java   | 17 ++++-------------
 .../androidx/media3/effect/DrawableOverlay.java | 13 +------------
 .../androidx/media3/effect/TextOverlay.java     | 14 +-------------
 3 files changed, 6 insertions(+), 38 deletions(-)

diff --git a/libraries/effect/src/main/java/androidx/media3/effect/BitmapOverlay.java b/libraries/effect/src/main/java/androidx/media3/effect/BitmapOverlay.java
index af7ef92799..fb0f4f2674 100644
--- a/libraries/effect/src/main/java/androidx/media3/effect/BitmapOverlay.java
+++ b/libraries/effect/src/main/java/androidx/media3/effect/BitmapOverlay.java
@@ -44,7 +44,7 @@ public abstract class BitmapOverlay extends TextureOverlay {
   private final float[] flipVerticallyMatrix;
 
   private int lastTextureId;
-  private boolean hasUpdatedBitmapReference;
+  private int lastBitmapGenerationId;
   private @Nullable Bitmap lastBitmap;
 
   /* package */ BitmapOverlay() {
@@ -75,22 +75,13 @@ public abstract class BitmapOverlay extends TextureOverlay {
     return new Size(checkNotNull(lastBitmap).getWidth(), checkNotNull(lastBitmap).getHeight());
   }
 
-  /**
-   * Returns whether the cached bitmap overlay should be updated using the latest {@linkplain
-   * #getBitmap bitmap}.
-   */
-  protected boolean shouldInvalidateCache() {
-    // Bitmap#sameAs() is documented as a slow method. Therefore, only use a reference comparison by
-    // default, instead of the deeper comparison done in sameAs.
-    return hasUpdatedBitmapReference;
-  }
-
   @Override
   public int getTextureId(long presentationTimeUs) throws VideoFrameProcessingException {
     Bitmap bitmap = getBitmap(presentationTimeUs);
-    hasUpdatedBitmapReference = bitmap != lastBitmap;
-    if (shouldInvalidateCache()) {
+    int generationId = bitmap.getGenerationId();
+    if (bitmap != lastBitmap || generationId != lastBitmapGenerationId) {
       lastBitmap = bitmap;
+      lastBitmapGenerationId = generationId;
       try {
         if (lastTextureId == C.INDEX_UNSET) {
           lastTextureId = GlUtil.generateTexture();
diff --git a/libraries/effect/src/main/java/androidx/media3/effect/DrawableOverlay.java b/libraries/effect/src/main/java/androidx/media3/effect/DrawableOverlay.java
index 3bdfd29097..f5c44fa420 100644
--- a/libraries/effect/src/main/java/androidx/media3/effect/DrawableOverlay.java
+++ b/libraries/effect/src/main/java/androidx/media3/effect/DrawableOverlay.java
@@ -33,7 +33,6 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
  */
 @UnstableApi
 public abstract class DrawableOverlay extends BitmapOverlay {
-  private boolean hasUpdatedDrawable;
   private @MonotonicNonNull Bitmap lastBitmap;
   private @MonotonicNonNull Drawable lastDrawable;
 
@@ -47,22 +46,12 @@ public abstract class DrawableOverlay extends BitmapOverlay {
    */
   public abstract Drawable getDrawable(long presentationTimeUs);
 
-  /**
-   * Returns whether the cached drawable overlay should be updated using the latest {@linkplain
-   * #getDrawable drawable}
-   */
-  @Override
-  protected final boolean shouldInvalidateCache() {
-    return hasUpdatedDrawable;
-  }
-
   @Override
   public Bitmap getBitmap(long presentationTimeUs) {
     Drawable overlayDrawable = getDrawable(presentationTimeUs);
     // TODO(b/227625365): Drawable doesn't implement the equals method, so investigate other methods
     //   of detecting the need to redraw the bitmap.
-    hasUpdatedDrawable = !overlayDrawable.equals(lastDrawable);
-    if (shouldInvalidateCache()) {
+    if (!overlayDrawable.equals(lastDrawable)) {
       lastDrawable = overlayDrawable;
       if (lastBitmap == null
           || lastBitmap.getWidth() != lastDrawable.getIntrinsicWidth()
diff --git a/libraries/effect/src/main/java/androidx/media3/effect/TextOverlay.java b/libraries/effect/src/main/java/androidx/media3/effect/TextOverlay.java
index 50730ac9ac..d806f0ad20 100644
--- a/libraries/effect/src/main/java/androidx/media3/effect/TextOverlay.java
+++ b/libraries/effect/src/main/java/androidx/media3/effect/TextOverlay.java
@@ -80,8 +80,6 @@ public abstract class TextOverlay extends BitmapOverlay {
 
   public static final int TEXT_SIZE_PIXELS = 100;
 
-  private boolean hasUpdatedText;
-
   private @MonotonicNonNull Bitmap lastBitmap;
   private @MonotonicNonNull SpannableString lastText;
 
@@ -92,20 +90,10 @@ public abstract class TextOverlay extends BitmapOverlay {
    */
   public abstract SpannableString getText(long presentationTimeUs);
 
-  /**
-   * Returns whether the cached text overlay should be updated using the latest {@linkplain #getText
-   * text}
-   */
-  @Override
-  protected final boolean shouldInvalidateCache() {
-    return hasUpdatedText;
-  }
-
   @Override
   public Bitmap getBitmap(long presentationTimeUs) {
     SpannableString overlayText = getText(presentationTimeUs);
-    hasUpdatedText = !overlayText.equals(lastText);
-    if (shouldInvalidateCache()) {
+    if (!overlayText.equals(lastText)) {
       lastText = overlayText;
       TextPaint textPaint = new TextPaint();
       textPaint.setTextSize(TEXT_SIZE_PIXELS);