java - 如何并排显示 2 个相机预览？[对于纸板应用]

Question

我正在尝试构建一个并排显示 2 个摄像头 View 的 Cardboard android 应用程序。[就像相机 View 适用于 VRCinema Android 应用一样。]

所以我研究了 GitHub 上的 Cardboard 代码，做了一些修改，到目前为止我能够使用 imageView 并排复制相同的图像。

到目前为止，代码看起来像这样。

AndroidManifest.XML

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.google.vrtoolkit.cardboard.samples.treasurehunt" >

    <uses-permission android:name="android.permission.NFC" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-feature android:name="android.hardware.camera" android:required="false" />
    <uses-feature android:name="android.hardware.camera.autofocus" android:required="false" />
    <uses-feature android:name="android.hardware.camera.front" android:required="false" />


    <uses-sdk android:minSdkVersion="14"/>
    <uses-feature android:glEsVersion="0x00020000" android:required="true" />

    <application
            android:allowBackup="true"
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name" >

        <activity
                android:screenOrientation="landscape"
                android:name=".MainActivity"
                android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

common_ui.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/ui_layout"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >


    <com.google.vrtoolkit.cardboard.CardboardView
        android:id="@+id/cardboard_view"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true" />

    <com.google.vrtoolkit.cardboard.samples.treasurehunt.CardboardOverlayView
        android:id="@+id/overlay"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_centerInParent="true" />



</RelativeLayout>

CardboardOverlayView.java

package com.google.vrtoolkit.cardboard.samples.treasurehunt;

        import android.content.Context;
        import android.graphics.Color;
        import android.graphics.Typeface;
        import android.util.AttributeSet;
        import android.util.TypedValue;
        import android.view.Gravity;
        import android.view.View;
        import android.view.ViewGroup;
        import android.view.animation.AlphaAnimation;
        import android.view.animation.Animation;
        import android.widget.ImageView;
        import android.widget.LinearLayout;
        import android.widget.TextView;

/**
 * Contains two sub-views to provide a simple stereo HUD.
 */
public class CardboardOverlayView extends LinearLayout {
    private static final String TAG = CardboardOverlayView_bkp1.class.getSimpleName();
    private final CardboardOverlayEyeView mLeftView;
    private final CardboardOverlayEyeView mRightView;
    private AlphaAnimation mTextFadeAnimation;

    public CardboardOverlayView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOrientation(HORIZONTAL);

        LayoutParams params = new LayoutParams(
                LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT, 1.0f);
        params.setMargins(0, 0, 0, 0);

        mLeftView = new CardboardOverlayEyeView(context, attrs);
        mLeftView.setLayoutParams(params);
        addView(mLeftView);

        mRightView = new CardboardOverlayEyeView(context, attrs);
        mRightView.setLayoutParams(params);
        addView(mRightView);

        // Set some reasonable defaults.
        setDepthOffset(0.016f);
        setColor(Color.rgb(150, 255, 180));
        setVisibility(View.VISIBLE);

        mTextFadeAnimation = new AlphaAnimation(1.0f, 0.0f);
        mTextFadeAnimation.setDuration(5000);
    }

    public void show3DToast(String message) {
        setText(message);
        setTextAlpha(1f);
        mTextFadeAnimation.setAnimationListener(new EndAnimationListener() {
            @Override
            public void onAnimationEnd(Animation animation) {
                setTextAlpha(0f);
            }
        });
        startAnimation(mTextFadeAnimation);
    }

    public void show3DImage() {
        setImg();

    }

    private abstract class EndAnimationListener implements Animation.AnimationListener {
        @Override public void onAnimationRepeat(Animation animation) {}
        @Override public void onAnimationStart(Animation animation) {}
    }

    private void setDepthOffset(float offset) {
        mLeftView.setOffset(offset);
        mRightView.setOffset(-offset);
    }


    //---------------------------------------------------------------------------------------------
    private void setImg(){
        mLeftView.imageView.setImageResource(R.drawable.mona_lisa);
        mRightView.imageView.setImageResource(R.drawable.mona_lisa);

    }
    //------------------------------------------------------------------------------------------

    private void setText(String text) {
        mLeftView.setText(text);
        mRightView.setText(text);
    }

    private void setTextAlpha(float alpha) {
        mLeftView.setTextViewAlpha(alpha);
        mRightView.setTextViewAlpha(alpha);
    }

    private void setColor(int color) {
        mLeftView.setColor(color);
        mRightView.setColor(color);
    }

    /**
     * A simple view group containing some horizontally centered text underneath a horizontally
     * centered image.
     *
     * This is a helper class for CardboardOverlayView.
     */
    private class CardboardOverlayEyeView extends ViewGroup {
        private final ImageView imageView;
        private final TextView textView;
        private float offset;

        public CardboardOverlayEyeView(Context context, AttributeSet attrs) {
            super(context, attrs);
            imageView = new ImageView(context, attrs);
            imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
            imageView.setAdjustViewBounds(true);  // Preserve aspect ratio.
            addView(imageView);

            textView = new TextView(context, attrs);
            textView.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 14.0f);
            textView.setTypeface(textView.getTypeface(), Typeface.BOLD);
            textView.setGravity(Gravity.CENTER);
            textView.setShadowLayer(3.0f, 0.0f, 0.0f, Color.DKGRAY);
            addView(textView);
        }

        public void setColor(int color) {
            //imageView.setColorFilter(color);
            textView.setTextColor(color);
        }

        public void setText(String text) {
            textView.setText(text);
        }

        public void setTextViewAlpha(float alpha) {
            textView.setAlpha(alpha);
        }

        public void setOffset(float offset) {
            this.offset = offset;
        }

        @Override
        protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
            // Width and height of this ViewGroup.
            final int width = right - left;
            final int height = bottom - top;

            // The size of the image, given as a fraction of the dimension as a ViewGroup. We multiply
            // both width and heading with this number to compute the image's bounding box. Inside the
            // box, the image is the horizontally and vertically centered.
            final float imageSize = 1.0f;

            // The fraction of this ViewGroup's height by which we shift the image off the ViewGroup's
            // center. Positive values shift downwards, negative values shift upwards.
            final float verticalImageOffset = -0.07f;

            // Vertical position of the text, specified in fractions of this ViewGroup's height.
            final float verticalTextPos = 0.52f;

            // Layout ImageView
            float imageMargin = (1.0f - imageSize) / 2.0f;
            float leftMargin = (int) (width * (imageMargin + offset));
            float topMargin = (int) (height * (imageMargin + verticalImageOffset));
            imageView.layout(
                    (int) leftMargin, (int) topMargin,
                    (int) (leftMargin + width * imageSize), (int) (topMargin + height * imageSize));

            // Layout TextView
            leftMargin = offset * width;
            topMargin = height * verticalTextPos;
            textView.layout(
                    (int) leftMargin, (int) topMargin,
                    (int) (leftMargin + width), (int) (topMargin + height * (1.0f - verticalTextPos)));
        }
    }
}

MainActivity.Java

package com.google.vrtoolkit.cardboard.samples.treasurehunt;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.hardware.Camera;
import android.net.Uri;
import android.os.Bundle;
import android.os.Vibrator;
import android.util.Log;
import android.widget.ImageView;
import com.google.vrtoolkit.cardboard.*;
import javax.microedition.khronos.egl.EGLConfig;
import java.nio.FloatBuffer;

/**
 * A Cardboard sample application.
 */
public class MainActivity extends CardboardActivity implements CardboardView.StereoRenderer {


    private static final int CAMERA_REQUEST = 1888;

    private static final String TAG = "MainActivity";
    private static final int CAPTURE_IMAGE_ACTIVITY_REQ = 0;

    Uri fileUri = null;
    ImageView photoImage = null;

    private static final float CAMERA_Z = 0.01f;
    private static final float TIME_DELTA = 0.3f;

    private static final float YAW_LIMIT = 0.12f;
    private static final float PITCH_LIMIT = 0.12f;

    // We keep the light always position just above the user.
    private final float[] mLightPosInWorldSpace = new float[]{0.0f, 2.0f, 0.0f, 1.0f};
    private final float[] mLightPosInEyeSpace = new float[4];

    private static final int COORDS_PER_VERTEX = 3;

    private final WorldLayoutData DATA = new WorldLayoutData();

    private FloatBuffer mFloorVertices;
    private FloatBuffer mFloorColors;
    private FloatBuffer mFloorNormals;

    private FloatBuffer mCubeVertices;
    private FloatBuffer mCubeColors;
    private FloatBuffer mCubeFoundColors;
    private FloatBuffer mCubeNormals;

    private int mGlProgram;
    private int mPositionParam;
    private int mNormalParam;
    private int mColorParam;
    private int mModelViewProjectionParam;
    private int mLightPosParam;
    private int mModelViewParam;
    private int mModelParam;
    private int mIsFloorParam;

    private float[] mModelCube;
    private float[] mCamera;
    private float[] mView;
    private float[] mHeadView;
    private float[] mModelViewProjection;
    private float[] mModelView;

    private float[] mModelFloor;

    private int mScore = 0;
    private float mObjectDistance = 12f;
    private float mFloorDepth = 20f;

    private Vibrator mVibrator;

    private CardboardOverlayView mOverlayView;

    public MainActivity() {
    }

    /**
     * Sets the view to our CardboardView and initializes the transformation matrices we will use
     * to render our scene.
     * //@param savedInstanceState
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.common_ui);
        CardboardView cardboardView = (CardboardView) findViewById(R.id.cardboard_view);
        cardboardView.setRenderer(this);
        setCardboardView(cardboardView);

        mModelCube = new float[16];
        mCamera = new float[16];
        mView = new float[16];
        mModelViewProjection = new float[16];
        mModelView = new float[16];
        mModelFloor = new float[16];
        mHeadView = new float[16];
        mVibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);


        mOverlayView = (CardboardOverlayView) findViewById(R.id.overlay);
        mOverlayView.show3DToast("Pull the magnet when you find an object.");

        mOverlayView.show3DImage();

    }

    @Override
    public void onRendererShutdown(){Log.i(TAG, "onRendererShutdown");
    }

    @Override
    public void onSurfaceChanged(int width, int height) {
        Log.i(TAG, "onSurfaceChanged");
    }

    /**
     * Creates the buffers we use to store information about the 3D world. OpenGL doesn't use Java
     * arrays, but rather needs data in a format it can understand. Hence we use ByteBuffers.
     *
     * @param config The EGL configuration used when creating the surface.
     */
    @Override
    public void onSurfaceCreated(EGLConfig config) {
        Log.i(TAG, "onSurfaceCreated");
    }

    /**
     * Prepares OpenGL ES before we draw a frame.
     *
     * @param headTransform The head transformation in the new frame.
     */
    @Override
    public void onNewFrame(HeadTransform headTransform) {
    }

    /**
     * Draws a frame for an eye. The transformation for that eye (from the camera) is passed in as
     * a parameter.
     *
     * @param transform The transformations to apply to render this eye.
     */
    @Override
    public void onDrawEye(EyeTransform transform) {
    }

    @Override
    public void onFinishFrame(Viewport viewport) {
    }

}

我注意到的要点:

• 我不需要 Intent ，我需要相机预览，以便稍后我可以用它做其他事情，比如拍照。
• 如果我尝试用 surfaceView 替换 imageView，我会在 common_ui.xml 中遇到错误“无法找到呈现问题类:CardboardOverlayView.java”。但是该文件在那里，并且它是一个已知和已报告的错误。
• 我能想到的另一种方法是每秒捕获并保存图像，并用图像更新 2 个 ImageView 。然而我不确定这是否是正确的方法或如何去做。

我还检查了自过去 3 天以来堆栈溢出中可用的所有链接。最接近我的问题的是 Android multuple camera preview - 但它并不能完全解决我的问题。我还浏览了 Android - Camera 文档并了解了他们如何使用 cameraPreview 和 surfaceView。

所以我的问题是，我现在需要做什么才能看到 CameraPreview [或包含 CameraPreview 的 surfaceView] 而不是 Imageview，以便我能够像横向模式下的分屏一样提供实时摄像头画面？

我希望这个问题足够详细。不过，如果您需要任何进一步的信息，尽管问。

Answer 1

基本上，您需要将相机绘制到 OpenGL 纹理中并显示该纹理。

我在这里写了两个版本，可以随意修改代码并添加拉取请求: https://github.com/Sveder/CardboardPassthrough