在 Jelly Bean 中,是否可以从相机预览填充的 SurfaceTexture 中创建 Renderscript 分配?我正在从 Android 源代码树中构建我的应用程序,所以我可以使用 @hide API,例如 Allocation.setSurfaceTexture()。但是我想避免使用 RS Graphics 已弃用的 API。这里的类似问题没有得到完全回答,也不是 JB 特有的。
尝试以下代码时遇到以下问题:
- 进入 Renderscript 的数据始终为零
- 要重复调用 onFrameAvailable 回调,我必须 updateTexImage(),因为当我调用 Allocation.ioReceive() 时,它在第一次之后不再被回调,并且 logcat 中有一个“无效的 EGLDisplay”。然而我认为 ioReceive() 是要走的路——它在内部也是 updateTexImage()。
- 支持的分配类型包括 RGBA8888 但不包括 NV21(这是相机预览格式),RS 代码将如何处理以这种方式格式化的数据?
(我知道我正在使用的设备确实支持请求的 VGA 分辨率)。
public class SampleRSCPCActivity extends Activity implements SurfaceTexture.OnFrameAvailableListener {
final static int DO_KERNEL = 0;
private static final String TAG="SAMPLERSCP";
private static Camera mCamera;
private Camera.Parameters mParams;
private int mFrameWidth, mFrameHeight;
private static SurfaceTexture mST;
private RenderScript mRS;
private Allocation mInAllocation;
private Allocation mOutAllocation;
private ScriptC_mono mScript;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i(TAG, "onCreate()");
createGUI();
createCamera();
createRSEnvironment();
}
public void onPause() {
Log.i(TAG, "onPause");
mCamera.stopPreview();
mCamera.release();
mCamera = null;
super.onPause();
}
private void createCamera() {
mCamera = Camera.open();
mParams = mCamera.getParameters();
mFrameWidth = 640;
mFrameHeight = 480;
mParams.setPreviewSize(mFrameWidth, mFrameHeight);
mParams.setPreviewFormat(ImageFormat.NV21);
mCamera.setParameters(mParams);
}
private void createRSEnvironment () {
mRS = RenderScript.create(this);
mScript = new ScriptC_mono(mRS, getResources(), R.raw.mono);
Type.Builder b = new Type.Builder(mRS, Element.U8(mRS));
int usage = Allocation.USAGE_SCRIPT | Allocation.USAGE_IO_INPUT;
mInAllocation = Allocation.createTyped(mRS, b.setX(mFrameWidth).setY(mFrameHeight).create(), usage);
mOutAllocation = Allocation.createTyped(mRS, b.setX(mFrameWidth).setY(mFrameHeight).create());
Log.i(TAG, "Getting SurfaceTexture from input Allocation");
mST = mInAllocation.getSurfaceTexture();
mST.setOnFrameAvailableListener(this);
try {
Log.i(TAG, "Setting SurfaceTexture for camera preview");
mCamera.setPreviewTexture(mST);
Log.i(TAG, "Starting preview");
mCamera.startPreview();
} catch (IOException e) {
Log.e(TAG, "Oops, something got wrong with setting the camera preview texture");
}
}
private void createGUI() {
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
}
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == DO_KERNEL)
Log.i(TAG, "Calling RS kernel");
mST.updateTexImage();
// mInAllocation.ioReceive();
mScript.forEach_root(mInAllocation, mOutAllocation);
Log.i(TAG, "Finishing RS");
mRS.finish();
Log.i(TAG, "Ok");
}
};
public void onFrameAvailable(SurfaceTexture st) {
Log.i(TAG, "onFrameAvailable callback");
handler.sendEmptyMessage(DO_KERNEL);
}
}
RS 代码相当简单,只是尝试检测非空数据:
void root(const uchar *v_in, uchar *v_out, uint32_t x, uint32_t y) {
if (*v_in != 0)
rsDebug("input data non null !", *v_in);
*v_out = (x / 640) * 255;
}