【Android开发VR实战】三.开发一个寻宝类VR游戏TreasureHunt

转载请注明出处：http://blog.csdn.net/linglongxin24/article/details/53939303

本文出自【DylanAndroid的博客】

---

【Android开发VR实战】三.开发一个寻宝类VR游戏TreasureHunt

VR即Virtual Reality虚拟现实。虚拟现实技术是一种能够创建和体验虚拟世界的计算机仿真系统它利用计算机生成一种模拟环境是一种多源信息融合的交互式的三维动态视景和实体行为的系统仿真使用户沉浸到该环境中。

那么，怎样在Android中去开发VR功能的APP呢？我们利用谷歌提供的开源SDK去实现一个360°全景游戏的功能。

接下来主要是针对谷歌提供的开发VR的SDK中的游戏样例进行翻译。

CardBoard：卡纸板，google早期推出的VR 开发集合，封装改动了Activity。GLSurfaceView 以及 Render等标准类的一层API，当中详细仔细的实现封在so库中。用户使用CardBoard提供的jar包以及so，依照API的规则使用OPENGL实现特定函数就可以开发VR程序

DayDream：白日梦，在CardBoard基础上的专业版，实现了很多其它的VR特性功能，如3D音效，全景视图，全景视频播放。控制器，封装的API和so也对应的增多。API更加有结构模块化。

TreasureHunt游戏场景包含一个平面接地网格和一个浮动 “宝藏”多维数据集。

当用户观看立方体时，立方体将变成金色。 用户能够直接激活Cardboard触发器在其Cardboard查看器上使用触摸触发器，或使用白日梦基于控制器的触发器仿真。 然后激活触发器,点击寻找宝藏，宝藏消失后随机又一次定位立方体。

一.在build.gradle中引入谷歌VR的SDK依赖

    compile 'com.google.vr:sdk-audio:1.10.0'
    compile 'com.google.vr:sdk-base:1.10.0'

二.注意支持的最小SDK

  minSdkVersion 19
  targetSdkVersion 25

三.界面布局文件

<?

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.vr.sdk.base.GvrView
        android:id="@+id/gvr_view"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true" />

</RelativeLayout>

四.绘制TreasureHunt的VR游戏界面代码

    /**
     * 将视图设置为我们的GvrView并初始化我们将用于渲染我们的场景的转换矩阵。

*/
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        initializeGvrView();

        modelCube = new float[16];
        camera = new float[16];
        view = new float[16];
        modelViewProjection = new float[16];
        modelView = new float[16];
        modelFloor = new float[16];
        tempPosition = new float[4];
        // Model first appears directly in front of user.
        modelPosition = new float[]{0.0f, 0.0f, -MAX_MODEL_DISTANCE / 2.0f};
        headRotation = new float[4];
        headView = new float[16];
        vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

        // Initialize 3D audio engine.
        gvrAudioEngine = new GvrAudioEngine(this, GvrAudioEngine.RenderingMode.BINAURAL_HIGH_QUALITY);
    }

    /**
     * 初始化VR显示界面
     */
    public void initializeGvrView() {
        setContentView(R.layout.common_ui);

        GvrView gvrView = (GvrView) findViewById(R.id.gvr_view);
        gvrView.setEGLConfigChooser(8, 8, 8, 8, 16, 8);
        /**设置渲染器**/
        gvrView.setRenderer(this);
        gvrView.setTransitionViewEnabled(true);

        /**使用Daydream耳机启用Cardboard触发反馈。
         * 这是一种使用现有Cardboard触发器API支持Daydream控制器输入进行基本交互的简单方法。**/
        gvrView.enableCardboardTriggerEmulation();

        if (gvrView.setAsyncReprojectionEnabled(true)) {
            /**异步投影，沉浸式，性能模式**/
            AndroidCompat.setSustainedPerformanceMode(this, true);
        }

        setGvrView(gvrView);
    }

    @Override
    public void onPause() {
        gvrAudioEngine.pause();
        super.onPause();
    }

    @Override
    public void onResume() {
        super.onResume();
        gvrAudioEngine.resume();
    }

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

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

    /**
     * 创建用于存储有关3D界面的信息的缓冲区。

* <p>
     * <p>OpenGL不使用Java数组。而是须要能够理解的格式的数据。

因此我们使用ByteBuffers。
     *
     * @param config The EGL configuration used when creating the surface.
     */
    @Override
    public void onSurfaceCreated(EGLConfig config) {
        Log.i(TAG, "onSurfaceCreated");
        GLES20.glClearColor(0.1f, 0.1f, 0.1f, 0.5f); // Dark background so text shows up well.

        ByteBuffer bbVertices = ByteBuffer.allocateDirect(WorldLayoutData.CUBE_COORDS.length * 4);
        bbVertices.order(ByteOrder.nativeOrder());
        cubeVertices = bbVertices.asFloatBuffer();
        cubeVertices.put(WorldLayoutData.CUBE_COORDS);
        cubeVertices.position(0);

        ByteBuffer bbColors = ByteBuffer.allocateDirect(WorldLayoutData.CUBE_COLORS.length * 4);
        bbColors.order(ByteOrder.nativeOrder());
        cubeColors = bbColors.asFloatBuffer();
        cubeColors.put(WorldLayoutData.CUBE_COLORS);
        cubeColors.position(0);

        ByteBuffer bbFoundColors =
                ByteBuffer.allocateDirect(WorldLayoutData.CUBE_FOUND_COLORS.length * 4);
        bbFoundColors.order(ByteOrder.nativeOrder());
        cubeFoundColors = bbFoundColors.asFloatBuffer();
        cubeFoundColors.put(WorldLayoutData.CUBE_FOUND_COLORS);
        cubeFoundColors.position(0);

        ByteBuffer bbNormals = ByteBuffer.allocateDirect(WorldLayoutData.CUBE_NORMALS.length * 4);
        bbNormals.order(ByteOrder.nativeOrder());
        cubeNormals = bbNormals.asFloatBuffer();
        cubeNormals.put(WorldLayoutData.CUBE_NORMALS);
        cubeNormals.position(0);

        // make a floor
        ByteBuffer bbFloorVertices = ByteBuffer.allocateDirect(WorldLayoutData.FLOOR_COORDS.length * 4);
        bbFloorVertices.order(ByteOrder.nativeOrder());
        floorVertices = bbFloorVertices.asFloatBuffer();
        floorVertices.put(WorldLayoutData.FLOOR_COORDS);
        floorVertices.position(0);

        ByteBuffer bbFloorNormals = ByteBuffer.allocateDirect(WorldLayoutData.FLOOR_NORMALS.length * 4);
        bbFloorNormals.order(ByteOrder.nativeOrder());
        floorNormals = bbFloorNormals.asFloatBuffer();
        floorNormals.put(WorldLayoutData.FLOOR_NORMALS);
        floorNormals.position(0);

        ByteBuffer bbFloorColors = ByteBuffer.allocateDirect(WorldLayoutData.FLOOR_COLORS.length * 4);
        bbFloorColors.order(ByteOrder.nativeOrder());
        floorColors = bbFloorColors.asFloatBuffer();
        floorColors.put(WorldLayoutData.FLOOR_COLORS);
        floorColors.position(0);

        int vertexShader = loadGLShader(GLES20.GL_VERTEX_SHADER, R.raw.light_vertex);
        int gridShader = loadGLShader(GLES20.GL_FRAGMENT_SHADER, R.raw.grid_fragment);
        int passthroughShader = loadGLShader(GLES20.GL_FRAGMENT_SHADER, R.raw.passthrough_fragment);

        cubeProgram = GLES20.glCreateProgram();
        GLES20.glAttachShader(cubeProgram, vertexShader);
        GLES20.glAttachShader(cubeProgram, passthroughShader);
        GLES20.glLinkProgram(cubeProgram);
        GLES20.glUseProgram(cubeProgram);

        checkGLError("Cube program");

        cubePositionParam = GLES20.glGetAttribLocation(cubeProgram, "a_Position");
        cubeNormalParam = GLES20.glGetAttribLocation(cubeProgram, "a_Normal");
        cubeColorParam = GLES20.glGetAttribLocation(cubeProgram, "a_Color");

        cubeModelParam = GLES20.glGetUniformLocation(cubeProgram, "u_Model");
        cubeModelViewParam = GLES20.glGetUniformLocation(cubeProgram, "u_MVMatrix");
        cubeModelViewProjectionParam = GLES20.glGetUniformLocation(cubeProgram, "u_MVP");
        cubeLightPosParam = GLES20.glGetUniformLocation(cubeProgram, "u_LightPos");

        checkGLError("Cube program params");

        floorProgram = GLES20.glCreateProgram();
        GLES20.glAttachShader(floorProgram, vertexShader);
        GLES20.glAttachShader(floorProgram, gridShader);
        GLES20.glLinkProgram(floorProgram);
        GLES20.glUseProgram(floorProgram);

        checkGLError("Floor program");

        floorModelParam = GLES20.glGetUniformLocation(floorProgram, "u_Model");
        floorModelViewParam = GLES20.glGetUniformLocation(floorProgram, "u_MVMatrix");
        floorModelViewProjectionParam = GLES20.glGetUniformLocation(floorProgram, "u_MVP");
        floorLightPosParam = GLES20.glGetUniformLocation(floorProgram, "u_LightPos");

        floorPositionParam = GLES20.glGetAttribLocation(floorProgram, "a_Position");
        floorNormalParam = GLES20.glGetAttribLocation(floorProgram, "a_Normal");
        floorColorParam = GLES20.glGetAttribLocation(floorProgram, "a_Color");

        checkGLError("Floor program params");

        Matrix.setIdentityM(modelFloor, 0);
        Matrix.translateM(modelFloor, 0, 0, -floorDepth, 0); // Floor appears below user.

        // Avoid any delays during start-up due to decoding of sound files.
        new Thread(
                new Runnable() {
                    @Override
                    public void run() {
                        // Start spatial audio playback of OBJECT_SOUND_FILE at the model position. The
                        // returned sourceId handle is stored and allows for repositioning the sound object
                        // whenever the cube position changes.
                        gvrAudioEngine.preloadSoundFile(OBJECT_SOUND_FILE);
                        sourceId = gvrAudioEngine.createSoundObject(OBJECT_SOUND_FILE);
                        gvrAudioEngine.setSoundObjectPosition(
                                sourceId, modelPosition[0], modelPosition[1], modelPosition[2]);
                        gvrAudioEngine.playSound(sourceId, true /* looped playback */);
                        // Preload an unspatialized sound to be played on a successful trigger on the cube.
                        gvrAudioEngine.preloadSoundFile(SUCCESS_SOUND_FILE);
                    }
                })
                .start();

        updateModelPosition();

        checkGLError("onSurfaceCreated");
    }

    /**
     * 将保存为资源的原始文本文件转换为OpenGL ES着色器。
     *
     * @param type  The type of shader we will be creating.
     * @param resId The resource ID of the raw text file about to be turned into a shader.
     * @return The shader object handler.
     */
    private int loadGLShader(int type, int resId) {
        String code = readRawTextFile(resId);
        int shader = GLES20.glCreateShader(type);
        GLES20.glShaderSource(shader, code);
        GLES20.glCompileShader(shader);

        // Get the compilation status.
        final int[] compileStatus = new int[1];
        GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compileStatus, 0);

        // If the compilation failed, delete the shader.
        if (compileStatus[0] == 0) {
            Log.e(TAG, "Error compiling shader: " + GLES20.glGetShaderInfoLog(shader));
            GLES20.glDeleteShader(shader);
            shader = 0;
        }

        if (shader == 0) {
            throw new RuntimeException("Error creating shader.");
        }

        return shader;
    }

    /**
     * 检查我们在OpenGL ES中是否有错误，假设有错误查看错误。

*
     * @param label Label to report in case of error.
     */
    private static void checkGLError(String label) {
        int error;
        while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
            Log.e(TAG, label + ": glError " + error);
            throw new RuntimeException(label + ": glError " + error);
        }
    }

    /**
     * 更新立方体的位置。
     */
    protected void updateModelPosition() {
        Matrix.setIdentityM(modelCube, 0);
        Matrix.translateM(modelCube, 0, modelPosition[0], modelPosition[1], modelPosition[2]);

        // Update the sound location to match it with the new cube position.
        if (sourceId != GvrAudioEngine.INVALID_ID) {
            gvrAudioEngine.setSoundObjectPosition(
                    sourceId, modelPosition[0], modelPosition[1], modelPosition[2]);
        }
        checkGLError("updateCubePosition");
    }

    /**
     * 将原始文本文件转换为字符串。
     *
     * @param resId 要转换为着色器的原始文本文件的资源ID。
     * @return 文本文件的上下文。或者在出现错误的情况下为null。
     */
    private String readRawTextFile(int resId) {
        InputStream inputStream = getResources().openRawResource(resId);
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder sb = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line).append("\n");
            }
            reader.close();
            return sb.toString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 在绘制视图之前准备OpenGL ES。

*
     * @param headTransform 新帧中的头变换。
     */
    @Override
    public void onNewFrame(HeadTransform headTransform) {
        setCubeRotation();

        // Build the camera matrix and apply it to the ModelView.
        Matrix.setLookAtM(camera, 0, 0.0f, 0.0f, CAMERA_Z, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);

        headTransform.getHeadView(headView, 0);

        // Update the 3d audio engine with the most recent head rotation.
        headTransform.getQuaternion(headRotation, 0);
        gvrAudioEngine.setHeadRotation(
                headRotation[0], headRotation[1], headRotation[2], headRotation[3]);
        // Regular update call to GVR audio engine.
        gvrAudioEngine.update();

        checkGLError("onReadyToDraw");
    }

    /**
     * 设置立方体旋转矩阵
     */
    protected void setCubeRotation() {
        Matrix.rotateM(modelCube, 0, TIME_DELTA, 0.5f, 0.5f, 1.0f);
    }

    /**
     * 为我们的视野画每一帧图。

*
     * @param eye 视图呈现。 包含全部必需的转换。

*/
    @Override
    public void onDrawEye(Eye eye) {
        GLES20.glEnable(GLES20.GL_DEPTH_TEST);
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);

        checkGLError("colorParam");

        // Apply the eye transformation to the camera.
        Matrix.multiplyMM(view, 0, eye.getEyeView(), 0, camera, 0);

        // Set the position of the light
        Matrix.multiplyMV(lightPosInEyeSpace, 0, view, 0, LIGHT_POS_IN_WORLD_SPACE, 0);

        // Build the ModelView and ModelViewProjection matrices
        // for calculating cube position and light.
        float[] perspective = eye.getPerspective(Z_NEAR, Z_FAR);
        Matrix.multiplyMM(modelView, 0, view, 0, modelCube, 0);
        Matrix.multiplyMM(modelViewProjection, 0, perspective, 0, modelView, 0);
        drawCube();

        // Set modelView for the floor, so we draw floor in the correct location
        Matrix.multiplyMM(modelView, 0, view, 0, modelFloor, 0);
        Matrix.multiplyMM(modelViewProjection, 0, perspective, 0, modelView, 0);
        drawFloor();
    }

    @Override
    public void onFinishFrame(Viewport viewport) {
    }

    /**
     * 绘制立方体。
     * <p>
     * <p>设置了全部的转换矩阵。

简单地将它们传递给着色器。
     */
    public void drawCube() {
        GLES20.glUseProgram(cubeProgram);

        GLES20.glUniform3fv(cubeLightPosParam, 1, lightPosInEyeSpace, 0);

        // Set the Model in the shader, used to calculate lighting
        GLES20.glUniformMatrix4fv(cubeModelParam, 1, false, modelCube, 0);

        // Set the ModelView in the shader, used to calculate lighting
        GLES20.glUniformMatrix4fv(cubeModelViewParam, 1, false, modelView, 0);

        // Set the position of the cube
        GLES20.glVertexAttribPointer(
                cubePositionParam, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, 0, cubeVertices);

        // Set the ModelViewProjection matrix in the shader.
        GLES20.glUniformMatrix4fv(cubeModelViewProjectionParam, 1, false, modelViewProjection, 0);

        // Set the normal positions of the cube, again for shading
        GLES20.glVertexAttribPointer(cubeNormalParam, 3, GLES20.GL_FLOAT, false, 0, cubeNormals);
        GLES20.glVertexAttribPointer(cubeColorParam, 4, GLES20.GL_FLOAT, false, 0,
                isLookingAtObject() ? cubeFoundColors : cubeColors);

        // Enable vertex arrays
        GLES20.glEnableVertexAttribArray(cubePositionParam);
        GLES20.glEnableVertexAttribArray(cubeNormalParam);
        GLES20.glEnableVertexAttribArray(cubeColorParam);

        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 36);

        // Disable vertex arrays
        GLES20.glDisableVertexAttribArray(cubePositionParam);
        GLES20.glDisableVertexAttribArray(cubeNormalParam);
        GLES20.glDisableVertexAttribArray(cubeColorParam);

        checkGLError("Drawing cube");
    }

    /**
     * 画地板。
     * <p>
     * <p>这将底层的数据馈入着色器。

注意。这不会输入关于灯的位置的数据，因此。假设我们重写我们的代码来绘制地板。照明可能
     * 看起来非常奇怪。

*/
    public void drawFloor() {
        GLES20.glUseProgram(floorProgram);

        // Set ModelView, MVP, position, normals, and color.
        GLES20.glUniform3fv(floorLightPosParam, 1, lightPosInEyeSpace, 0);
        GLES20.glUniformMatrix4fv(floorModelParam, 1, false, modelFloor, 0);
        GLES20.glUniformMatrix4fv(floorModelViewParam, 1, false, modelView, 0);
        GLES20.glUniformMatrix4fv(floorModelViewProjectionParam, 1, false, modelViewProjection, 0);
        GLES20.glVertexAttribPointer(
                floorPositionParam, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, 0, floorVertices);
        GLES20.glVertexAttribPointer(floorNormalParam, 3, GLES20.GL_FLOAT, false, 0, floorNormals);
        GLES20.glVertexAttribPointer(floorColorParam, 4, GLES20.GL_FLOAT, false, 0, floorColors);

        GLES20.glEnableVertexAttribArray(floorPositionParam);
        GLES20.glEnableVertexAttribArray(floorNormalParam);
        GLES20.glEnableVertexAttribArray(floorColorParam);

        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 24);

        GLES20.glDisableVertexAttribArray(floorPositionParam);
        GLES20.glDisableVertexAttribArray(floorNormalParam);
        GLES20.glDisableVertexAttribArray(floorColorParam);

        checkGLError("drawing floor");
    }

    /**
     * 当点击或拉动Cardboard触发器时调用。
     */
    @Override
    public void onCardboardTrigger() {
        Log.i(TAG, "onCardboardTrigger");

        if (isLookingAtObject()) {
            successSourceId = gvrAudioEngine.createStereoSound(SUCCESS_SOUND_FILE);
            gvrAudioEngine.playSound(successSourceId, false /* looping disabled */);
            hideObject();
        }

        // Always give user feedback.
        vibrator.vibrate(50);
    }

    /**
     * 方法作用：隐藏物体即为对象找到一个新的随机位置。
     * <p>
     * 方法说明：我们将环绕Y轴旋转它，使它看不见，然后向上或向下一点点。
     */
    protected void hideObject() {
        float[] rotationMatrix = new float[16];
        float[] posVec = new float[4];

        // First rotate in XZ plane, between 90 and 270 deg away, and scale so that we vary
        // the object's distance from the user.
        float angleXZ = (float) Math.random() * 180 + 90;
        Matrix.setRotateM(rotationMatrix, 0, angleXZ, 0f, 1f, 0f);
        float oldObjectDistance = objectDistance;
        objectDistance =
                (float) Math.random() * (MAX_MODEL_DISTANCE - MIN_MODEL_DISTANCE) + MIN_MODEL_DISTANCE;
        float objectScalingFactor = objectDistance / oldObjectDistance;
        Matrix.scaleM(rotationMatrix, 0, objectScalingFactor, objectScalingFactor, objectScalingFactor);
        Matrix.multiplyMV(posVec, 0, rotationMatrix, 0, modelCube, 12);

        float angleY = (float) Math.random() * 80 - 40; // Angle in Y plane, between -40 and 40.
        angleY = (float) Math.toRadians(angleY);
        float newY = (float) Math.tan(angleY) * objectDistance;

        modelPosition[0] = posVec[0];
        modelPosition[1] = newY;
        modelPosition[2] = posVec[2];

        updateModelPosition();
    }

    /**
     * 通过计算对象在眼睛空间中的位置来检查用户是否正在查看对象。
     *
     * @return 假设用户正在查看对象。则为true。
     */
    private boolean isLookingAtObject() {
        // Convert object space to camera space. Use the headView from onNewFrame.
        Matrix.multiplyMM(modelView, 0, headView, 0, modelCube, 0);
        Matrix.multiplyMV(tempPosition, 0, modelView, 0, POS_MATRIX_MULTIPLY_VEC, 0);

        float pitch = (float) Math.atan2(tempPosition[1], -tempPosition[2]);
        float yaw = (float) Math.atan2(tempPosition[0], -tempPosition[2]);

        return Math.abs(pitch) < PITCH_LIMIT && Math.abs(yaw) < YAW_LIMIT;
    }

五.GitHub