Distorted Android

  private static float[] mTmpMatrix = new float[16];

  private static float[] mTmpResult = new float[4];

  private static float[] mTmpPoint  = new float[4];

  private static float mMinX,mMaxX,mMinY,mMaxY;

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void magnifyDir()

    {

    Matrix.multiplyMV(mTmpResult,0,mTmpMatrix,0,mTmpPoint,0);

    float nx = mTmpResult[0]/mTmpResult[3];

    float ny = mTmpResult[1]/mTmpResult[3];

    if( nx<mMinX ) mMinX = nx;

    if( nx>mMaxX ) mMaxX = nx;

    if( ny<mMinY ) mMinY = ny;

    if( ny>mMaxY ) mMaxY = ny;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

// return a float which describes how much larger an object must be so that it appears to be (about)

// 'marginInPixels' pixels larger in each direction. Used in Postprocessing.

  float magnify(DistortedOutputSurface projection, float halfX, float halfY, float halfZ, float marginInPixels)

    {

    mMinX = Integer.MAX_VALUE;

    mMaxX = Integer.MIN_VALUE;

    mMinY = Integer.MAX_VALUE;

    mMaxY = Integer.MIN_VALUE;

    mTmpPoint[3] = 1.0f;

    Matrix.multiplyMM(mTmpMatrix, 0, projection.mProjectionMatrix, 0, mViewMatrix, 0);

    mTmpPoint[0] = +halfX; mTmpPoint[1] = +halfY; mTmpPoint[2] = +halfZ; magnifyDir();

    mTmpPoint[0] = +halfX; mTmpPoint[1] = +halfY; mTmpPoint[2] = -halfZ; magnifyDir();

    mTmpPoint[0] = +halfX; mTmpPoint[1] = -halfY; mTmpPoint[2] = +halfZ; magnifyDir();

    mTmpPoint[0] = +halfX; mTmpPoint[1] = -halfY; mTmpPoint[2] = -halfZ; magnifyDir();

    mTmpPoint[0] = -halfX; mTmpPoint[1] = +halfY; mTmpPoint[2] = +halfZ; magnifyDir();

    mTmpPoint[0] = -halfX; mTmpPoint[1] = +halfY; mTmpPoint[2] = -halfZ; magnifyDir();

    mTmpPoint[0] = -halfX; mTmpPoint[1] = -halfY; mTmpPoint[2] = +halfZ; magnifyDir();

    mTmpPoint[0] = -halfX; mTmpPoint[1] = -halfY; mTmpPoint[2] = -halfZ; magnifyDir();

    float xLenInPixels = projection.mWidth *(mMaxX-mMinX)/2;

    float yLenInPixels = projection.mHeight*(mMaxY-mMinY)/2;

    // already margin / min(xLen,yLen) is the size of the halo.

    // Here we need a bit more because we are marking not only the halo, but a little bit around

    // it as well so that the (blur for example) will be smooth on the edges. Thus the 2.0f.

    //

    // mMipmap ( 1.0 , 0.5, 0.25, 0.125 ) - we need to make the size of the halo independent

    // of postprocessing effect quality.

    return projection.mMipmap*2.0f*marginInPixels/( xLenInPixels>yLenInPixels ? yLenInPixels:xLenInPixels );

    }