📅  最后修改于: 2023-12-03 15:24:49.185000             🧑  作者: Mango
增强现实(Augmented Reality,AR)是一种将实时虚拟信息叠加到真实环境中的技术。随着移动设备的普及,AR技术被广泛地应用到各个领域。本文将介绍如何构建一个简单的增强现实Android应用程序。
在开始之前,需要确保以下前提条件已经具备:
运行Android Studio,点击“File -> New -> New Project”创建一个新的Android项目。
在Vuforia官网上注册一个免费账户,下载最新版本的Vuforia SDK。将下载后的Vuforia SDK解压到本地目录中。
右键单击Android项目中的app目录,选择“New -> Folder -> JNI Folder”创建一个新的JNI目录。将Vuforia SDK中的所有文件复制到该目录中。将Vuforia SDK中的“build.xml”文件拷贝到项目文件夹中,并执行以下命令:
$ cd <path-to-project>
$ ant -Dvuforia.src.path=<path-to-Vuforia-SDK>/src -f build.xml
在Android项目的build.gradle文件中,增加以下代码:
android {
...
defaultConfig {
...
ndk {
abiFilters "armeabi-v7a", "x86"
}
}
sourceSets {
main {
jniLibs.srcDirs = ['src/main/jniLibs']
}
}
...
}
在Android Studio中,创建一个新的Java类,继承自Activity。此类将用于启动Vuforia引擎并渲染AR视图:
public class VuforiaActivity extends Activity implements VuforiaUpdateCallback {
private static final float NEAR_CLIP_DISTANCE = 10.0f;
private static final float FAR_CLIP_DISTANCE = 1000.0f;
private VuforiaSession mVuforiaSession;
private VuforiaRenderer mRenderer;
private Camera mCamera;
private boolean mHasSurface;
private int mViewWidth;
private int mViewHeight;
private boolean mIsPortrait;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFlags(
WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
mCamera = Camera.open();
mHasSurface = false;
mViewWidth = 0;
mViewHeight = 0;
mIsPortrait = false;
}
@Override
protected void onResume() {
super.onResume();
if (mHasSurface) {
mVuforiaSession.onResume();
mRenderer.onSurfaceCreated(mCamera);
}
}
@Override
protected void onPause() {
super.onPause();
if (mHasSurface) {
mVuforiaSession.onPause();
mRenderer.onSurfaceDestroyed();
}
}
@Override
protected void onDestroy() {
super.onDestroy();
mRenderer.destroy();
mVuforiaSession.destroy();
}
@Override
public void onVuforiaUpdate(VuforiaState state) {
if (mHasSurface) {
if (mIsPortrait) {
state.setProjectionMatrix(Matrix44FTool
.createProjectionMatrixForLandscapeLeft(FAR_CLIP_DISTANCE, NEAR_CLIP_DISTANCE));
} else {
state.setProjectionMatrix(Matrix44FTool
.createProjectionMatrixForLandscapeLeft(FAR_CLIP_DISTANCE, NEAR_CLIP_DISTANCE));
}
mRenderer.onUpdate(state, mCamera);
}
}
}
创建一个新的Java类VuforiaRenderer,它将继承自Renderer,并实现VuforiaUpdateCallback接口:
public class VuforiaRenderer extends Renderer implements VuforiaUpdateCallback {
private static final String LOG_TAG = VuforiaRenderer.class.getSimpleName();
private Mesh mQuadMesh;
private ShaderProgram mShaderProgram;
private Texture2D mTexture;
private boolean mHasShaderProgram;
public VuforiaRenderer() {
mQuadMesh = new QuadMesh(1.0f, 1.0f, 1.0f, 1.0f);
}
@Override
public void onUpdate(VuforiaState state, Camera camera) {
if (!mHasShaderProgram) {
initShaderProgram();
}
GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
Matrix44F modelMatrix = Matrix44FTool.createIdentity();
Matrix44F viewMatrix = Matrix44FTool.createLookAt(camera.getPosition(), camera.getTarget(), camera.getUp());
Matrix44F projectionMatrix = state.getProjectionMatrix();
mShaderProgram.use();
mShaderProgram.setUniform("modelViewProjectionMatrix",
projectionMatrix.multiply(viewMatrix).multiply(modelMatrix));
mTexture.bind();
mQuadMesh.draw(mShaderProgram);
mTexture.unbind();
mShaderProgram.unuse();
}
private void initShaderProgram() {
mShaderProgram = new ShaderProgram(R.raw.vertex_shader, R.raw.fragment_shader);
if (!mShaderProgram.compileAndLink()) {
Log.e(LOG_TAG, "Failed to compile and link shader program.");
return;
}
mShaderProgram.use();
mShaderProgram.setUniform("texture", 0);
mHasShaderProgram = true;
}
public void onSurfaceCreated(Camera camera) {
mTexture = new Texture2D(BitmapTool.fromResource(R.drawable.model));
GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
GLES20.glEnable(GLES20.GL_DEPTH_TEST);
GLES20.glDepthFunc(GLES20.GL_LESS);
camera.setNearClipDistance(NEAR_CLIP_DISTANCE);
camera.setFarClipDistance(FAR_CLIP_DISTANCE);
}
public void onSurfaceDestroyed() {
GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
GLES20.glDisable(GLES20.GL_DEPTH_TEST);
GLES20.glDepthFunc(GLES20.GL_LESS);
}
public void destroy() {
if (mTexture != null) {
mTexture.dispose();
}
if (mShaderProgram != null) {
mShaderProgram.dispose();
}
if (mQuadMesh != null) {
mQuadMesh.dispose();
}
}
}
将模型文件(.obj或.3ds格式)拷贝到“app/src/main/assets”目录下。使用Android Studio的Asset Manager工具来加载模型文件:
private void loadModel() {
InputStream in = null;
try {
AssetManager assets = getAssets();
in = assets.open("model.obj");
ObjParser parser = new ObjParser();
parser.parse(in);
mModel = parser.getResult();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (in != null) {
try {
in.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
将Android设备连接到电脑,运行应用程序。摄像头会自动启动并开始检测已注册的图像。如果检测到匹配的图像,AR视图将显示出增强现实场景。
本文介绍了如何构建一个简单的增强现实Android应用程序。通过Vuforia AR引擎,我们可以轻松地实现增强现实技术并将其应用到各个领域。希望本文能够对您有所帮助。