使用gluUnProject输出值不正确...为什么?

时间:2011-11-07 15:58:42

标签: android opengl-es

我有一个简单的Square with openGL es 1和Android 1.5。广场被画在屏幕的中央。

我希望当用户按下屏幕或在屏幕上移动手指时,方块会移动到该位置。为了做到这一点,我尝试使用GLuUnProject,我试图获得与用手指触摸的窗口XY坐标匹配的opengl坐标(将多边形转换为将来的多边形),并且我正在写入坐标logcat中。

我接收的坐标不是真正的坐标,是错误的坐标。例如,此logcat表示屏幕右侧的水平移动:

11-07 15:54:37.221: DEBUG/XXXXXXXXX(213): X: -0.003236022
11-07 15:54:37.221: DEBUG/XXXXXXXXX(213): Y: -0.047979668
11-07 15:54:37.241: DEBUG/XXXXXXXXX(213): X: -0.003236022
11-07 15:54:37.251: DEBUG/XXXXXXXXX(213): Y: -0.047807075
11-07 15:54:39.110: DEBUG/XXXXXXXXX(213): X: 0.03469036
11-07 15:54:39.110: DEBUG/XXXXXXXXX(213): Y: 0.04418271
11-07 15:54:43.021: DEBUG/XXXXXXXXX(213): X: -0.029469538
11-07 15:54:43.021: DEBUG/XXXXXXXXX(213): Y: -0.034172554
11-07 15:54:43.051: DEBUG/XXXXXXXXX(213): X: -0.026708115
11-07 15:54:43.051: DEBUG/XXXXXXXXX(213): Y: -0.034172554
11-07 15:54:43.081: DEBUG/XXXXXXXXX(213): X: -0.018596433
11-07 15:54:43.081: DEBUG/XXXXXXXXX(213): Y: -0.034172554
11-07 15:54:43.111: DEBUG/XXXXXXXXX(213): X: -0.013073588
11-07 15:54:43.111: DEBUG/XXXXXXXXX(213): Y: -0.034172554
11-07 15:54:43.141: DEBUG/XXXXXXXXX(213): X: -0.0039263717
11-07 15:54:43.141: DEBUG/XXXXXXXXX(213): Y: -0.033999965
11-07 15:54:43.162: DEBUG/XXXXXXXXX(213): X: -0.0011649576
11-07 15:54:43.162: DEBUG/XXXXXXXXX(213): Y: -0.033827372
11-07 15:54:43.191: DEBUG/XXXXXXXXX(213): X: 7.335304E-4
11-07 15:54:43.191: DEBUG/XXXXXXXXX(213): Y: -0.033654787

这是源代码:

public class MySurfaceView extends GLSurfaceView implements Renderer {  
private float INITIAL_Z = -35.0f;   
private Context context;
private Square square;
private float xrot;                 //X Rotation
private float yrot;                 //Y Rotation
private float zrot;                 //Z Rotation    
private float z = INITIAL_Z;            //Profundidad en el eje Z
private float x = 0.0f;             //eje X
private float y = 0.0f;             //eje Y

private MatrixGrabber mg = new MatrixGrabber(); //create the matrix grabber object in your initialization code    
byte horizontal=-1; //0: LEFT  1:CENTER  2:RIGHT
byte vertical=-1; //0: TOP  1:CENTER  2:BOTTOM
float startX=-1;
float startY=-1;
float xMovement=0.0f;
float yMovement=0.0f;
private boolean movement_mode=false;

public MySurfaceView(Context context, Bitmap image, int width, byte horizontal, byte vertical) {
    super(context);
    this.context = context;
    setEGLConfigChooser(8, 8, 8, 8, 16, 0); //fondo transparente
    getHolder().setFormat(PixelFormat.TRANSLUCENT); //fondo transparente
    //Transformamos esta clase en renderizadora
    this.setRenderer(this);
    //Request focus, para que los botones reaccionen
    this.requestFocus();
    this.setFocusableInTouchMode(true);
    square = new Square(image);
    this.horizontal=horizontal;
    this.vertical=vertical;
}

public void onSurfaceCreated(GL10 gl, EGLConfig config) {
    MyGl=gl;
    gl.glDisable(GL10.GL_DITHER);               //dithering OFF
    gl.glEnable(GL10.GL_TEXTURE_2D);            //Texture Mapping ON
    gl.glShadeModel(GL10.GL_SMOOTH);            //Smooth Shading 
    gl.glClearDepthf(1.0f);                     //Depth Buffer Setup
    gl.glEnable(GL10.GL_DEPTH_TEST);            //Depth Testing ON
    gl.glDepthFunc(GL10.GL_LEQUAL);
    gl.glClearColor(0,0,0,0); //fondo transparente
    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);         
    //Cargamos la textura del cubo.
    square.loadGLTexture(gl, this.context);     
}

public void onDrawFrame(GL10 gl) {
    //Limpiamos pantalla y Depth Buffer
    gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
    gl.glLoadIdentity();
    //Dibujado
    gl.glTranslatef(x, y, z);           //Move z units into the screen
    //gl.glScalef(0.8f, 0.8f, 0.8f);            //Escalamos para que quepa en la pantalla
    //Rotamos sobre los ejes.
    gl.glRotatef(xrot, 1.0f, 0.0f, 0.0f);   //X
    gl.glRotatef(yrot, 0.0f, 1.0f, 0.0f);   //Y
    gl.glRotatef(zrot, 0.0f, 0.0f, 1.0f);   //Z
    //Dibujamos el cuadrado
    square.draw(gl);    
    mg.getCurrentProjection(gl);
    mg.getCurrentModelView(gl);

}

//si el surface cambia, resetea la vista, imagino que esto pasa cuando cambias de modo portrait/landscape o sacas el teclado físico en móviles tipo Droid.
public void onSurfaceChanged(GL10 gl, int width, int height) {
    if(height == 0) {                       
        height = 1;                         
    }
    gl.glViewport(0, 0, width, height);     //Reset Viewport
    gl.glMatrixMode(GL10.GL_PROJECTION);    //Select Projection Matrix
    gl.glLoadIdentity();                    //Reset Projection Matrix
    //Aspect Ratio de la ventana
    GLU.gluPerspective(gl, 45.0f, (float)width / (float)height, 0.1f, 100.0f);
    gl.glMatrixMode(GL10.GL_MODELVIEW);     //Select Modelview Matrix
    gl.glLoadIdentity();                    //Reset Modelview Matrix
}

public boolean onTouchEvent(MotionEvent event) {
    float [] outputCoords=getOpenGLCoords(event.getX(), event.getY(), 0);
    x=(outputCoords[0]/outputCoords[3]);
    y=(outputCoords[1]/outputCoords[3]);
    //z=outputCoords[2]/outputCoords[3];
    Log.d("XXXXXXXXX", "X: "+x);
    Log.d("XXXXXXXXX", "Y: "+y);        
    return true; //El evento ha sido manejado
}

public float[] getOpenGLCoords(float xWin,float yWin,float zWin)
{
    int screenW=SectionManager.instance.getDisplayWidth();
    int screenH=SectionManager.instance.getDisplayHeight();
    //CODE FOR TRANSLATING FROM SCREEN COORDINATES TO OPENGL COORDINATES
    float [] modelMatrix = new float[16];
    float [] projMatrix = new float[16];
    modelMatrix=mg.mModelView;
    projMatrix=mg.mProjection;          
    int [] mView = new int[4];
    mView[0] = 0;
    mView[1] = 0;
    mView[2] = screenW; //width
    mView[3] = screenH; //height
    float [] outputCoords = new float[4];
    GLU.gluUnProject(xWin, ((float)screenH)-yWin, zWin, modelMatrix, 0, projMatrix, 0, mView, 0, outputCoords, 0);
    return outputCoords;
}
}

1 个答案:

答案 0 :(得分:1)

你的价值观似乎很合理。你会得到一个越来越大的x值(绝对值递减的负值)和保持大致相同的y值,这对应于向右移动(假设转换中没有任何非零旋转)管道)。

由于4.7的z平移和-4.8的近似值,得到的0.1 z坐标也是合理的。有了这样的z平移和45度的视野,你得到的x和y值确实应该非常小(我认为大约在[-1,1]左右)。

所以我认为你的代码就像它应该的那样工作。你期望的坐标是什么?请不要对像素的顺序说些什么。