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.
diff --git a/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index 11a48d9..28f3dc2 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -34,6 +34,46 @@
namespace android {
+// Transform matrices
+static float mtxIdentity[16] = {
+ 1, 0, 0, 0,
+ 0, 1, 0, 0,
+ 0, 0, 1, 0,
+ 0, 0, 0, 1,
+};
+static float mtxFlipH[16] = {
+ -1, 0, 0, 0,
+ 0, 1, 0, 0,
+ 0, 0, 1, 0,
+ 1, 0, 0, 1,
+};
+static float mtxFlipV[16] = {
+ 1, 0, 0, 0,
+ 0, -1, 0, 0,
+ 0, 0, 1, 0,
+ 0, 1, 0, 1,
+};
+static float mtxRot90[16] = {
+ 0, 1, 0, 0,
+ -1, 0, 0, 0,
+ 0, 0, 1, 0,
+ 1, 0, 0, 1,
+};
+static float mtxRot180[16] = {
+ -1, 0, 0, 0,
+ 0, -1, 0, 0,
+ 0, 0, 1, 0,
+ 1, 1, 0, 1,
+};
+static float mtxRot270[16] = {
+ 0, -1, 0, 0,
+ 1, 0, 0, 0,
+ 0, 0, 1, 0,
+ 0, 1, 0, 1,
+};
+
+static void mtxMul(float out[16], const float a[16], const float b[16]);
+
SurfaceTexture::SurfaceTexture(GLuint tex) :
mBufferCount(MIN_BUFFER_SLOTS), mCurrentTexture(INVALID_BUFFER_SLOT),
mLastQueued(INVALID_BUFFER_SLOT), mTexName(tex) {
@@ -121,6 +161,8 @@
}
mSlots[buf].mOwnedByClient = false;
mLastQueued = buf;
+ mLastQueuedCrop = mNextCrop;
+ mLastQueuedTransform = mNextTransform;
return OK;
}
@@ -138,17 +180,17 @@
mSlots[buf].mOwnedByClient = false;
}
-status_t SurfaceTexture::setCrop(const Rect& reg) {
+status_t SurfaceTexture::setCrop(const Rect& crop) {
LOGV("SurfaceTexture::setCrop");
Mutex::Autolock lock(mMutex);
- // XXX: How should we handle crops?
+ mNextCrop = crop;
return OK;
}
status_t SurfaceTexture::setTransform(uint32_t transform) {
LOGV("SurfaceTexture::setTransform");
Mutex::Autolock lock(mMutex);
- // XXX: How should we handle transforms?
+ mNextTransform = transform;
return OK;
}
@@ -162,8 +204,12 @@
// Initially both mCurrentTexture and mLastQueued are INVALID_BUFFER_SLOT,
// so this check will fail until a buffer gets queued.
if (mCurrentTexture != mLastQueued) {
- // XXX: Figure out the right target.
+ // Update the SurfaceTexture state.
mCurrentTexture = mLastQueued;
+ mCurrentCrop = mLastQueuedCrop;
+ mCurrentTransform = mLastQueuedTransform;
+
+ // Update the GL texture object.
EGLImageKHR image = mSlots[mCurrentTexture].mEglImage;
if (image == EGL_NO_IMAGE_KHR) {
EGLDisplay dpy = eglGetCurrentDisplay();
@@ -183,6 +229,49 @@
return OK;
}
+void SurfaceTexture::getTransformMatrix(float mtx[16]) {
+ LOGV("SurfaceTexture::updateTexImage");
+ Mutex::Autolock lock(mMutex);
+
+ float* xform = mtxIdentity;
+ switch (mCurrentTransform) {
+ case 0:
+ xform = mtxIdentity;
+ break;
+ case NATIVE_WINDOW_TRANSFORM_FLIP_H:
+ xform = mtxFlipH;
+ break;
+ case NATIVE_WINDOW_TRANSFORM_FLIP_V:
+ xform = mtxFlipV;
+ break;
+ case NATIVE_WINDOW_TRANSFORM_ROT_90:
+ xform = mtxRot90;
+ break;
+ case NATIVE_WINDOW_TRANSFORM_ROT_180:
+ xform = mtxRot180;
+ break;
+ case NATIVE_WINDOW_TRANSFORM_ROT_270:
+ xform = mtxRot270;
+ break;
+ default:
+ LOGE("getTransformMatrix: unknown transform: %d", mCurrentTransform);
+ }
+
+ sp<GraphicBuffer>& buf(mSlots[mCurrentTexture].mGraphicBuffer);
+ float tx = float(mCurrentCrop.left) / float(buf->getWidth());
+ float ty = float(mCurrentCrop.bottom) / float(buf->getHeight());
+ float sx = float(mCurrentCrop.width()) / float(buf->getWidth());
+ float sy = float(mCurrentCrop.height()) / float(buf->getHeight());
+ float crop[16] = {
+ sx, 0, 0, sx*tx,
+ 0, sy, 0, sy*ty,
+ 0, 0, 1, 0,
+ 0, 0, 0, 1,
+ };
+
+ mtxMul(mtx, crop, xform);
+}
+
void SurfaceTexture::freeAllBuffers() {
for (int i = 0; i < NUM_BUFFER_SLOTS; i++) {
mSlots[i].mGraphicBuffer = 0;
@@ -214,4 +303,26 @@
return image;
}
+static void mtxMul(float out[16], const float a[16], const float b[16]) {
+ out[0] = a[0]*b[0] + a[4]*b[1] + a[8]*b[2] + a[12]*b[3];
+ out[1] = a[1]*b[0] + a[5]*b[1] + a[9]*b[2] + a[13]*b[3];
+ out[2] = a[2]*b[0] + a[6]*b[1] + a[10]*b[2] + a[14]*b[3];
+ out[3] = a[3]*b[0] + a[7]*b[1] + a[11]*b[2] + a[15]*b[3];
+
+ out[4] = a[0]*b[4] + a[4]*b[5] + a[8]*b[6] + a[12]*b[7];
+ out[5] = a[1]*b[4] + a[5]*b[5] + a[9]*b[6] + a[13]*b[7];
+ out[6] = a[2]*b[4] + a[6]*b[5] + a[10]*b[6] + a[14]*b[7];
+ out[7] = a[3]*b[4] + a[7]*b[5] + a[11]*b[6] + a[15]*b[7];
+
+ out[8] = a[0]*b[8] + a[4]*b[9] + a[8]*b[10] + a[12]*b[11];
+ out[9] = a[1]*b[8] + a[5]*b[9] + a[9]*b[10] + a[13]*b[11];
+ out[10] = a[2]*b[8] + a[6]*b[9] + a[10]*b[10] + a[14]*b[11];
+ out[11] = a[3]*b[8] + a[7]*b[9] + a[11]*b[10] + a[15]*b[11];
+
+ out[12] = a[0]*b[12] + a[4]*b[13] + a[8]*b[14] + a[12]*b[15];
+ out[13] = a[1]*b[12] + a[5]*b[13] + a[9]*b[14] + a[13]*b[15];
+ out[14] = a[2]*b[12] + a[6]*b[13] + a[10]*b[14] + a[14]*b[15];
+ out[15] = a[3]*b[12] + a[7]*b[13] + a[11]*b[14] + a[15]*b[15];
+}
+
}; // namespace android