Fix a bug in SurfaceTexture::setBufferCount.

We need to reset mCurrentTexture and mLastQueued in setBufferCount
because it frees all of the buffers associated with the buffer slots.

Change-Id: Ie2f834ec1c07ce7a4ab9b2b5fc5fe8c294010c60

2 files changed, 7 insertions, 2 deletions

diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index ff92e08..cbc15d8 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -113,8 +113,11 @@ private:
     int mBufferCount;
 
     // mCurrentTexture is the buffer slot index of the buffer that is currently
-    // bound to the OpenGL texture. A value of INVALID_BUFFER_SLOT, indicating
-    // that no buffer is currently bound to the texture.
+    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
+    // indicating that no buffer slot is currently bound to the texture. Note,
+    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
+    // that no buffer is bound to the texture. A call to setBufferCount will
+    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
     int mCurrentTexture;
 
     // mLastQueued is the buffer slot index of the most recently enqueued buffer.
diff --git a/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index 10f309a..11a48d9 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -55,6 +55,8 @@ status_t SurfaceTexture::setBufferCount(int bufferCount) {
     Mutex::Autolock lock(mMutex);
     freeAllBuffers();
     mBufferCount = bufferCount;
+    mCurrentTexture = INVALID_BUFFER_SLOT;
+    mLastQueued = INVALID_BUFFER_SLOT;
     return OK;
 }