ARCore相机似乎不支持takePicture。
https://developers.google.com/ar/reference/java/com/google/ar/core/Camera有人知道如何在ARCore中拍照吗？
3个回答
9
我假设您指的是相机所拍摄到的图像和增强现实物体的图片。在高层次上，您需要获取写入外部存储的许可以保存照片，从OpenGL复制帧，然后将其保存为png格式（例如）。以下是具体步骤：
将
接下来，向
在
最后一步是将按钮添加到
将
WRITE_EXTERNAL_STORAGE 权限添加到 AndroidManifest.xml 文件中。 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
然后将CameraPermissionHelper更改为迭代遍历相机和写入外部存储权限，以确保它们已被授予。
private static final String REQUIRED_PERMISSIONS[] = {
Manifest.permission.WRITE_EXTERNAL_STORAGE,
Manifest.permission.CAMERA
};
/**
* Check to see we have the necessary permissions for this app.
*/
public static boolean hasCameraPermission(Activity activity) {
for (String p : REQUIRED_PERMISSIONS) {
if (ContextCompat.checkSelfPermission(activity, p) !=
PackageManager.PERMISSION_GRANTED) {
return false;
}
}
return true;
}
/**
* Check to see we have the necessary permissions for this app,
* and ask for them if we don't.
*/
public static void requestCameraPermission(Activity activity) {
ActivityCompat.requestPermissions(activity, REQUIRED_PERMISSIONS,
CAMERA_PERMISSION_CODE);
}
/**
* Check to see if we need to show the rationale for this permission.
*/
public static boolean shouldShowRequestPermissionRationale(Activity activity) {
for (String p : REQUIRED_PERMISSIONS) {
if (ActivityCompat.shouldShowRequestPermissionRationale(activity, p)) {
return true;
}
}
return false;
}
接下来，向
HelloARActivity添加几个字段来跟踪帧的尺寸和布尔值以指示何时保存图片。 private int mWidth;
private int mHeight;
private boolean capturePicture = false;
在onSurfaceChanged()中设置宽度和高度。
public void onSurfaceChanged(GL10 gl, int width, int height) {
mDisplayRotationHelper.onSurfaceChanged(width, height);
GLES20.glViewport(0, 0, width, height);
mWidth = width;
mHeight = height;
}
在
onDrawFrame()的底部，添加一个检查捕获标志的步骤。这应该在所有其他绘图操作之后进行。 if (capturePicture) {
capturePicture = false;
SavePicture();
}
然后为按钮添加onClick方法以拍摄照片，并添加实际代码保存图像：
public void onSavePicture(View view) {
// Here just a set a flag so we can copy
// the image from the onDrawFrame() method.
// This is required for OpenGL so we are on the rendering thread.
this.capturePicture = true;
}
/**
* Call from the GLThread to save a picture of the current frame.
*/
public void SavePicture() throws IOException {
int pixelData[] = new int[mWidth * mHeight];
// Read the pixels from the current GL frame.
IntBuffer buf = IntBuffer.wrap(pixelData);
buf.position(0);
GLES20.glReadPixels(0, 0, mWidth, mHeight,
GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, buf);
// Create a file in the Pictures/HelloAR album.
final File out = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES) + "/HelloAR", "Img" +
Long.toHexString(System.currentTimeMillis()) + ".png");
// Make sure the directory exists
if (!out.getParentFile().exists()) {
out.getParentFile().mkdirs();
}
// Convert the pixel data from RGBA to what Android wants, ARGB.
int bitmapData[] = new int[pixelData.length];
for (int i = 0; i < mHeight; i++) {
for (int j = 0; j < mWidth; j++) {
int p = pixelData[i * mWidth + j];
int b = (p & 0x00ff0000) >> 16;
int r = (p & 0x000000ff) << 16;
int ga = p & 0xff00ff00;
bitmapData[(mHeight - i - 1) * mWidth + j] = ga | r | b;
}
}
// Create a bitmap.
Bitmap bmp = Bitmap.createBitmap(bitmapData,
mWidth, mHeight, Bitmap.Config.ARGB_8888);
// Write it to disk.
FileOutputStream fos = new FileOutputStream(out);
bmp.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.flush();
fos.close();
runOnUiThread(new Runnable() {
@Override
public void run() {
showSnackbarMessage("Wrote " + out.getName(), false);
}
});
}
最后一步是将按钮添加到
activity_main.xml布局的末尾。<Button
android:id="@+id/fboRecord_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignStart="@+id/surfaceview"
android:layout_alignTop="@+id/surfaceview"
android:onClick="onSavePicture"
android:text="Snap"
tools:ignore="OnClick"/>
- Clayton Wilkinson
1
1新代码没有onSurfaceChanged函数，如果额外编写，则永远不会被调用。 - Maveňツ
5
获取图像缓冲区
在最新的ARCore SDK中，我们可以通过公共类Frame访问图像缓冲区。以下是示例代码，可让我们访问图像缓冲区。
private void onSceneUpdate(FrameTime frameTime) {
try {
Frame currentFrame = sceneView.getArFrame();
Image currentImage = currentFrame.acquireCameraImage();
int imageFormat = currentImage.getFormat();
if (imageFormat == ImageFormat.YUV_420_888) {
Log.d("ImageFormat", "Image format is YUV_420_888");
}
}
如果您在回调函数setOnUpdateListener()中注册了
onSceneUpdate()函数，则每次更新都会调用它。图像将采用YUV_420_888格式，但它将具有本机高分辨率相机的全视场。此外，请勿忘记通过调用
currentImage.close()关闭接收到的图像资源。否则，在下一次运行onSceneUpdate时，您将收到一个ResourceExhaustedException异常。
将获取的图像缓冲区写入文件
以下实现将YUV缓冲区转换为压缩后的JPEG字节数组。private static byte[] NV21toJPEG(byte[] nv21, int width, int height) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
YuvImage yuv = new YuvImage(nv21, ImageFormat.NV21, width, height, null);
yuv.compressToJpeg(new Rect(0, 0, width, height), 100, out);
return out.toByteArray();
}
public static void WriteImageInformation(Image image, String path) {
byte[] data = null;
data = NV21toJPEG(YUV_420_888toNV21(image),
image.getWidth(), image.getHeight());
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(path));
bos.write(data);
bos.flush();
bos.close();
}
private static byte[] YUV_420_888toNV21(Image image) {
byte[] nv21;
ByteBuffer yBuffer = image.getPlanes()[0].getBuffer();
ByteBuffer uBuffer = image.getPlanes()[1].getBuffer();
ByteBuffer vBuffer = image.getPlanes()[2].getBuffer();
int ySize = yBuffer.remaining();
int uSize = uBuffer.remaining();
int vSize = vBuffer.remaining();
nv21 = new byte[ySize + uSize + vSize];
//U and V are swapped
yBuffer.get(nv21, 0, ySize);
vBuffer.get(nv21, ySize, vSize);
uBuffer.get(nv21, ySize + vSize, uSize);
return nv21;
}
- nbsrujan
5
缺少方法/类YUV_420_888toNV21。此外，由于onSceneUpdate被不断调用，我们是否应该将图像保存到字段/属性中，并在想要保存图像时调用“WriteImageInformation”？ - MichaelThePotato
1@MichaelThePotato 我已经更新了答案。你可以自行决定何时将更新后的图像缓冲区写入文件。 - nbsrujan
1如何在纵向模式下使用上述代码？AcquireCameraImage方向总是横向(640 x 480)。我需要先旋转图像吗？如果是的话，应该怎么做？ - Kushagra
1@Kushagra ARCore 在横向模式下处理图像。您无法获取纵向模式下的图像。在获取缓冲区后，您可能需要手动旋转图像。 - nbsrujan
1谢谢@nbsrujan，我使用以下代码成功将图像转为纵向：
Image image = Objects.requireNonNull(ArCoreManager.getInstance().getArFrame()).acquireCameraImage();
if (isPortrait()) {
Matrix matrix = new Matrix();
matrix.postRotate(90);
imageBitmap = Bitmap.createBitmap(imageBitmap, 0, 0, image.getWidth(), image.getHeight(), matrix, true);
} - Kushagra2
抱歉回复晚了。您可以使用代码在ARCore中点击图片：
private String generateFilename() {
String date =
new SimpleDateFormat("yyyyMMddHHmmss", java.util.Locale.getDefault()).format(new Date());
return Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES) + File.separator + "Sceneform/" + date + "_screenshot.jpg";
}
private void saveBitmapToDisk(Bitmap bitmap, String filename) throws IOException {
File out = new File(filename);
if (!out.getParentFile().exists()) {
out.getParentFile().mkdirs();
}
try (FileOutputStream outputStream = new FileOutputStream(filename);
ByteArrayOutputStream outputData = new ByteArrayOutputStream()) {
bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputData);
outputData.writeTo(outputStream);
outputStream.flush();
outputStream.close();
} catch (IOException ex) {
throw new IOException("Failed to save bitmap to disk", ex);
}
}
private void takePhoto() {
final String filename = generateFilename();
/*ArSceneView view = fragment.getArSceneView();*/
mSurfaceView = findViewById(R.id.surfaceview);
// Create a bitmap the size of the scene view.
final Bitmap bitmap = Bitmap.createBitmap(mSurfaceView.getWidth(), mSurfaceView.getHeight(),
Bitmap.Config.ARGB_8888);
// Create a handler thread to offload the processing of the image.
final HandlerThread handlerThread = new HandlerThread("PixelCopier");
handlerThread.start();
// Make the request to copy.
PixelCopy.request(mSurfaceView, bitmap, (copyResult) -> {
if (copyResult == PixelCopy.SUCCESS) {
try {
saveBitmapToDisk(bitmap, filename);
} catch (IOException e) {
Toast toast = Toast.makeText(DrawAR.this, e.toString(),
Toast.LENGTH_LONG);
toast.show();
return;
}
Snackbar snackbar = Snackbar.make(findViewById(android.R.id.content),
"Photo saved", Snackbar.LENGTH_LONG);
snackbar.setAction("Open in Photos", v -> {
File photoFile = new File(filename);
Uri photoURI = FileProvider.getUriForFile(DrawAR.this,
DrawAR.this.getPackageName() + ".ar.codelab.name.provider",
photoFile);
Intent intent = new Intent(Intent.ACTION_VIEW, photoURI);
intent.setDataAndType(photoURI, "image/*");
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
startActivity(intent);
});
snackbar.show();
} else {
Log.d("DrawAR", "Failed to copyPixels: " + copyResult);
Toast toast = Toast.makeText(DrawAR.this,
"Failed to copyPixels: " + copyResult, Toast.LENGTH_LONG);
toast.show();
}
handlerThread.quitSafely();
}, new Handler(handlerThread.getLooper()));
}
- kiran nanda
2
1更多细节可以在这里找到：https://codelabs.developers.google.com/codelabs/sceneform-intro/index.html?index=..%2F..io2018#14 - M. Noreikis
为什么生成的图像结果在我放置物体的区域会有白色空间？ - chia yongkang
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