java - 当我尝试创建 Opengl ES 环境时，我的应用程序不断崩溃

Question

我正在遵循有关如何使用图形创建您自己的 Open GL ES 环境的 Android 教程。除了教程似乎跳过了他们假设我们知道要包含的代码之外，我在让我的应用程序保持打开状态而没有错误消息“不幸的是，MyApp 已停止”五秒后遇到了问题应用程序打开。我不相信这是三角形类造成的，因为我注释掉了三角形对象并尝试再次运行它，但同样的事情发生了。我还包含了应包含在 list 中的必要代码。

这是我的代码(Open GL ES 代码位于虚线之间):

    public class MainActivity extends ActionBarActivity {

private GLSurfaceView mGLView;
private GLSurfaceView.Renderer MyRenderer;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mGLView=new MyGLSurfaceView(this);
    setContentView(mGLView);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container,
                false);
        return rootView;
    }
}

//....................................................................................................
class MyGLSurfaceView extends GLSurfaceView{

    public MyGLSurfaceView(Context context){
        super(context);
        MyRenderer=new MyGlRenderer();
        setRenderer(MyRenderer);
        setEGLContextClientVersion(2);
        setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
    }
}

//Triangle mTriangle;

public class MyGlRenderer implements GLSurfaceView.Renderer{
    @Override
    public void onSurfaceCreated(GL10 unused, EGLConfig config){
        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

        //mTriangle= new Triangle();
    }
    @Override
    public void onDrawFrame(GL10 unused){

        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
        //mTriangle.draw();
    }
    @Override
    public void onSurfaceChanged(GL10 unused, int width, int height){
        GLES20.glViewport(0,0,width,height);
    }

}

public class Triangle{

    private FloatBuffer vertexBuffer;
    static final int COORDS_PER_VERTEX=3;
    float triangleCoords[]={
        0.0f, 0.622008459f, 0.0f,//top
        -0.5f, -0.311004243f, 0.0f, //bottom left
        0.5f, -0.311004242f,0.0f//bottom right
    };

    int mProgram;
    float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };

    private final String vertexShaderCode =
            "attribute vec4 vPosition;" +
            "void main() {" +
            "  gl_Position = vPosition;" +
            "}";

        private final String fragmentShaderCode =
            "precision mediump float;" +
            "uniform vec4 vColor;" +
            "void main() {" +
            "  gl_FragColor = vColor;" +
            "}";

    public Triangle(){
        ByteBuffer bb=ByteBuffer.allocateDirect(
                triangleCoords.length*4);
        bb.order(ByteOrder.nativeOrder());
        vertexBuffer=bb.asFloatBuffer();
        vertexBuffer.put(triangleCoords);
        vertexBuffer.position(0);

        int vertexShader=loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
        int fragmentShader=loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);

        mProgram=GLES20.glCreateProgram();
        GLES20.glAttachShader(mProgram, vertexShader);
        GLES20.glAttachShader(mProgram, fragmentShader);
        GLES20.glLinkProgram(mProgram);

    }

    public int loadShader(int type, String shaderCode){
        int shader=GLES20.glCreateShader(type);
        GLES20.glShaderSource(shader, shaderCode);
        GLES20.glCompileShader(shader);
        return shader;
    }

    static final int vertexStride = COORDS_PER_VERTEX * 3;
    static final int vertexCount = 3;


    public void draw(){
        GLES20.glUseProgram(mProgram);
        int mPositionHandle= GLES20.glGetAttribLocation(mProgram, "vPosition");
        GLES20.glEnableVertexAttribArray(mPositionHandle);
        GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
                                     GLES20.GL_FLOAT, false,
                                      vertexStride, vertexBuffer);
        int mColorHandle=GLES20.glGetUniformLocation(mProgram,"vColor");
        GLES20.glUniform4fv(mColorHandle, 1, color,0);
        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
        GLES20.glDisableVertexAttribArray(mPositionHandle);
    }
}
//....................................................................................................
    }

这是日志行为，供任何需要它的人使用:

06-23 11:44:30.385: D/ActivityThread(27794): setTargetHeapUtilization:0.25 06-23 11:44:30.385: D/ActivityThread(27794): setTargetHeapIdealFree:8388608 06-23 11:44:30.385: D/ActivityThread(27794): setTargetHeapConcurrentStart:2097152 06-23 11:44:30.535: W/dalvikvm(27794): threadid=1: thread exiting with uncaught exception (group=0x40ee7438) 06-23 11:44:30.535: E/AndroidRuntime(27794): FATAL EXCEPTION: main 06-23 11:44:30.535: E/AndroidRuntime(27794): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapp5/com.example.myapp5.MainActivity}: java.lang.IllegalStateException: setRenderer has already been called for this instance. 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.ActivityThread.access$700(ActivityThread.java:143) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.os.Handler.dispatchMessage(Handler.java:99) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.os.Looper.loop(Looper.java:137) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.ActivityThread.main(ActivityThread.java:4953) 06-23 11:44:30.535: E/AndroidRuntime(27794): at java.lang.reflect.Method.invokeNative(Native Method) 06-23 11:44:30.535: E/AndroidRuntime(27794): at java.lang.reflect.Method.invoke(Method.java:511) 06-23 11:44:30.535: E/AndroidRuntime(27794): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1004) 06-23 11:44:30.535: E/AndroidRuntime(27794): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:771) 06-23 11:44:30.535: E/AndroidRuntime(27794): at dalvik.system.NativeStart.main(Native Method) 06-23 11:44:30.535: E/AndroidRuntime(27794): Caused by: java.lang.IllegalStateException: setRenderer has already been called for this instance. 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.opengl.GLSurfaceView.checkRenderThreadState(GLSurfaceView.java:1810) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.opengl.GLSurfaceView.setEGLContextClientVersion(GLSurfaceView.java:472) 06-23 11:44:30.535: E/AndroidRuntime(27794): at com.example.myapp5.MainActivity$MyGLSurfaceView.(MainActivity.java:80) 06-23 11:44:30.535: E/AndroidRuntime(27794): at com.example.myapp5.MainActivity.onCreate(MainActivity.java:31) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.Activity.performCreate(Activity.java:5160) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) 06-23 11:44:30.535: E/AndroidRuntime(27794): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074) 06-23 11:44:30.535: E/AndroidRuntime(27794): ... 11 more

Answer 1

setEGLContextClientVersion() 需要在 setRenderer() 之前调用，如文档中所述:http://developer.android.com/reference/android/opengl/GLSurfaceView.html#setEGLContextClientVersion(int) .

在您复制的堆栈跟踪中还有一个提示，表明这是您的问题:

java.lang.IllegalStateException: setRenderer has already been called for this instance.