2 files changed, 19 insertions, 2 deletions
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index 2b31462..62c3a4a 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -188,6 +188,11 @@ private:
 
     status_t setBufferCountServerLocked(int bufferCount);
 
+    // computeCurrentTransformMatrix computes the transform matrix for the
+    // current texture.  It uses mCurrentTransform and the current GraphicBuffer
+    // to compute this matrix and stores it in mCurrentTransformMatrix.
+    void computeCurrentTransformMatrix();
+
     enum { INVALID_BUFFER_SLOT = -1 };
 
     struct BufferSlot {
@@ -322,6 +327,11 @@ private:
     // gets set to mLastQueuedTransform each time updateTexImage is called.
     uint32_t mCurrentTransform;
 
+    // mCurrentTransformMatrix is the transform matrix for the current texture.
+    // It gets computed by computeTransformMatrix each time updateTexImage is
+    // called.
+    float mCurrentTransformMatrix[16];
+
     // mCurrentTimestamp is the timestamp for the current texture. It
     // gets set to mLastQueuedTimestamp each time updateTexImage is called.
     int64_t mCurrentTimestamp;
@@ -362,6 +372,7 @@ private:
     // variables of SurfaceTexture objects. It must be locked whenever the
     // member variables are accessed.
     mutable Mutex mMutex;
+
 };
 
 // ----------------------------------------------------------------------------
diff --git a/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index ee97dcf..2cda4c8 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -96,6 +96,7 @@ SurfaceTexture::SurfaceTexture(GLuint tex) :
     sp<ISurfaceComposer> composer(ComposerService::getComposerService());
     mGraphicBufferAlloc = composer->createGraphicBufferAlloc();
     mNextCrop.makeInvalid();
+    memcpy(mCurrentTransformMatrix, mtxIdentity, sizeof(mCurrentTransformMatrix));
 }
 
 SurfaceTexture::~SurfaceTexture() {
@@ -547,6 +548,7 @@ status_t SurfaceTexture::updateTexImage() {
         mCurrentCrop = mSlots[buf].mCrop;
         mCurrentTransform = mSlots[buf].mTransform;
         mCurrentTimestamp = mSlots[buf].mTimestamp;
+        computeCurrentTransformMatrix();
         mDequeueCondition.signal();
     } else {
         // We always bind the texture even if we don't update its contents.
@@ -596,8 +598,12 @@ GLenum SurfaceTexture::getCurrentTextureTarget() const {
 }
 
 void SurfaceTexture::getTransformMatrix(float mtx[16]) {
-    LOGV("SurfaceTexture::getTransformMatrix");
     Mutex::Autolock lock(mMutex);
+    memcpy(mtx, mCurrentTransformMatrix, sizeof(mCurrentTransformMatrix));
+}
+
+void SurfaceTexture::computeCurrentTransformMatrix() {
+    LOGV("SurfaceTexture::computeCurrentTransformMatrix");
 
     float xform[16];
     for (int i = 0; i < 16; i++) {
@@ -684,7 +690,7 @@ void SurfaceTexture::getTransformMatrix(float mtx[16]) {
     // coordinate of 0, so SurfaceTexture must behave the same way.  We don't
     // want to expose this to applications, however, so we must add an
     // additional vertical flip to the transform after all the other transforms.
-    mtxMul(mtx, mtxFlipV, mtxBeforeFlipV);
+    mtxMul(mCurrentTransformMatrix, mtxFlipV, mtxBeforeFlipV);
 }
 
 nsecs_t SurfaceTexture::getTimestamp() {