Android openGL渲染器返回空指針異常

Question

我正在創建一個使用GL10的應用程序，它由三個類組成，

A類擴展了Activity。 B類實現渲染器。 C類延伸活動。

C類包含3D立方體的數據，B類是渲染器，A類顯示它。

要顯示它，我使用在類A中的以下方法，

GLCubeRenderer ourSurface = new GLCubeRenderer(); 

public void onCreate(Bundle savedInstanceState){ 
    super.onCreate(savedInstanceState); 



    GLSurfaceView glSurfaceView = 
     (GLSurfaceView) findViewById(R.id.ourCube); 
    glSurfaceView.setRenderer(ourSurface); 
    setContentView(R.layout.cubelayout); 

} 

和XML是：

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

<com.mastermind.GLCubeRenderer 
    android:id="@+id/ourCube" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    /> 


</RelativeLayout> 

的問題是，在用於類A中的線'的Java代碼glSurfaceView.setRenderer（ourSurface）;」返回一個空指針異常。

B類（渲染器）的代碼：

private GLCube cube = new GLCube(); 
static Context context; 
public static float xAngle; 

public static float yAngle; 

final float[] ambient = { 0.1f, 1, 1, 1 }; 
final float[] position = { 45, 20, 0, 1 }; 
final float[] direction = { 0, -1, 0 }; 

public GLCubeRenderer() { 
    cube = new GLCube(); 



} 

@Override 
public void onSurfaceCreated(GL10 gl, EGLConfig config) { 
    // TODO Auto-generated method stub 
    gl.glDisable(GL10.GL_DITHER); 
    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST); 
    gl.glEnable(GL10.GL_LIGHT1); 
    gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_DIFFUSE, ambient, 0); 
    gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_POSITION, position, 0); 
    gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_SPOT_DIRECTION, direction, 0); 
    gl.glLightf(GL10.GL_LIGHT1, GL10.GL_SPOT_CUTOFF, 30.0f); 
    gl.glClearColor(.0f, 0, .0f, 0); 
    gl.glClearDepthf(1f); 


} 

@Override 
public void onDrawFrame(GL10 gl) { 
    // TODO Auto-generated method stub 
    gl.glDisable(GL10.GL_DITHER); 
    gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); 

    gl.glMatrixMode(GL10.GL_MODELVIEW); 
    gl.glLoadIdentity(); 
    GLU.gluLookAt(gl, 0, 0, -5, 0, 0, 0, 0, 2, 0); 

    gl.glRotatef(xAngle, 0, xAngle, 0); 
    // gl.glRotatef(yAngle, yAngle, 0, yAngle); 

    gl.glActiveTexture(GL10.GL_TEXTURE0); 
    gl.glTexEnvx(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,  GL10.GL_MODULATE); 
    gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT); 
    gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT); 

    cube.draw(gl); 
} 



@Override 
public void onSurfaceChanged(GL10 gl, int width, int height) { 
    // TODO Auto-generated method stub 
    gl.glViewport(0, 0, width, height); 
    float ratio = (float) width/height; 
    gl.glMatrixMode(GL10.GL_PROJECTION); 
    gl.glLoadIdentity(); 
    gl.glFrustumf(-ratio, ratio, -1, 1f, 1, 25); 

} 

和類C代碼：

private float vertices[] = { 
     1, 1, -1, // p0-top front right 
     1, -1, -1, // p1-bottom front right 
     -1, -1, -1, // p2-bottom front left 
     -1, 1, -1, // p3-front top left 
     1, 1, 1, // p4-top back right 
     1, -1, 1, // p5-bottom back right 
     -1, -1, 1, // p6-bottom back left 
     -1, 1, 1 // p7-front back left 

}; 

// Buffer for our vertices 
private FloatBuffer vertBuff; 

// Index for our points e.g. p0 = 0f, 1f, in vert Index 
private short[] pIndex = { 
     3, 4, 0, 
     0, 4, 1, 
     3, 0, 1, 
     3, 7, 4, 
     7, 6, 4, 
     7, 3, 6, 
     3, 1, 2, 
     1, 6, 2, 
     6, 3, 2, 
     1, 4, 5, 
     5, 6, 1, 
     6, 5, 4 
     }; 

// Buffer for points index 
private ShortBuffer pBuff; 

// Triangle constructor 
public GLCube() { 

    // Construction of vertices 
    // byte buffer for vertices 
    ByteBuffer bBuff = ByteBuffer.allocateDirect(vertices.length * 4); 
    bBuff.order(ByteOrder.nativeOrder()); 
    vertBuff = bBuff.asFloatBuffer(); 
    vertBuff.put(vertices); 
    vertBuff.position(0); 

    // Construction of points 
    // point byte buffer 
    ByteBuffer pointByteBuff = ByteBuffer.allocateDirect(pIndex.length * 2); 
    pointByteBuff.order(ByteOrder.nativeOrder()); 
    pBuff = pointByteBuff.asShortBuffer(); 
    pBuff.put(pIndex); 
    pBuff.position(0); 
} 



public void draw(GL10 gl) { 

    gl.glFrontFace(GL10.GL_CW); 
    gl.glEnable(GL10.GL_CULL_FACE); 
    gl.glCullFace(GL10.GL_BACK); 
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); 
    gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff); 
    gl.glDrawElements(GL10.GL_TRIANGLES, pIndex.length, GL10.GL_UNSIGNED_SHORT, pBuff); 
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); 
    gl.glDisable(GL10.GL_CULL_FACE); 
} 

赦免問題的長度，但沒有人有任何解決方案？

Answer 1

我不明白，你把XML定義爲GLCubeRenderer，它和我們的表面一樣。

GLSurfaceView glSurfaceView = 
    (GLSurfaceView) findViewById(R.id.ourCube); 

和

<com.mastermind.GLCubeRenderer 
    android:id="@+id/ourCube" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    /> 

話又說回來越來越ourCube的參考保持時將其轉換爲GLSurfaceView。

GLCubeRenderer是否擴展了GLSurfaceView？在這種情況下，你是否試圖將此Surfaceview的渲染器設置爲同一類的實例？

我想你可能會在這裏混淆課程。