Implement crop & transform for SurfaceTexture.
This change adds support for the setCrop and setTransform methods of the
SurfaceTexture C++ class. The crop and transform for the current
texture will be accessed by applications as a single texture coordinate
transform matrix.
Change-Id: I6482bf96f680e5c175364e848936db3908d6c8f8
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index cbc15d8..09cf2a2 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -70,6 +70,26 @@
// target texture belongs is bound to the calling thread.
status_t updateTexImage();
+ // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
+ // associated with the texture image set by the most recent call to
+ // updateTexImage.
+ //
+ // This transform matrix maps 2D homogeneous texture coordinates of the form
+ // (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
+ // coordinate that should be used to sample that location from the texture.
+ // Sampling the texture outside of the range of this transform is undefined.
+ //
+ // This transform is necessary to compensate for transforms that the stream
+ // content producer may implicitly apply to the content. By forcing users of
+ // a SurfaceTexture to apply this transform we avoid performing an extra
+ // copy of the data that would be needed to hide the transform from the
+ // user.
+ //
+ // The matrix is stored in column-major order so that it may be passed
+ // directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
+ // functions.
+ void getTransformMatrix(float mtx[16]);
+
private:
// freeAllBuffers frees the resources (both GraphicBuffer and EGLImage) for
@@ -120,11 +140,37 @@
// reset mCurrentTexture to INVALID_BUFFER_SLOT.
int mCurrentTexture;
+ // mCurrentCrop is the crop rectangle that applies to the current texture.
+ // It gets set to mLastQueuedCrop each time updateTexImage is called.
+ Rect mCurrentCrop;
+
+ // mCurrentTransform is the transform identifier for the current texture. It
+ // gets set to mLastQueuedTransform each time updateTexImage is called.
+ uint32_t mCurrentTransform;
+
// mLastQueued is the buffer slot index of the most recently enqueued buffer.
// At construction time it is initialized to INVALID_BUFFER_SLOT, and is
// updated each time queueBuffer is called.
int mLastQueued;
+ // mLastQueuedCrop is the crop rectangle for the buffer that was most
+ // recently queued. This gets set to mNextCrop each time queueBuffer gets
+ // called.
+ Rect mLastQueuedCrop;
+
+ // mLastQueuedTransform is the transform identifier for the buffer that was
+ // most recently queued. This gets set to mNextTransform each time
+ // queueBuffer gets called.
+ uint32_t mLastQueuedTransform;
+
+ // mNextCrop is the crop rectangle that will be used for the next buffer
+ // that gets queued. It is set by calling setCrop.
+ Rect mNextCrop;
+
+ // mNextTransform is the transform identifier that will be used for the next
+ // buffer that gets queued. It is set by calling setTransform.
+ uint32_t mNextTransform;
+
// mTexName is the name of the OpenGL texture to which streamed images will
// be bound when updateTexImage is called. It is set at construction time
// changed with a call to setTexName.