Opengl ES Android-围绕自身旋转相机

Question

I am developing a terrain generation app on android with Opengl ES, and I am having problems rotating the camera around itself ( the FPS effect to make it clear). what I am doing is to move the view with Matrix.setLookAtM and then rotating the view after translating it to the origin.This is a snippet of the code:

    Matrix.setLookAtM(mViewMatrix, 0, xrot, eyeY, yrot, xrot, lookY, yrot,0.0f, 1.0f, 0.0f); 

    Matrix.translateM(mViewMatrix,0,-xrot,0f,-yrot);
    Matrix.rotateM(mViewMatrix, 0, mAngleX+mAngleY, 0.0f, 1.0f,0.0f);
    Matrix.translateM(mViewMatrix,0,xrot,0f,yrot);

where xrot , yrot , mAngleX+mAngleY are input from the touchscreen. This code works only in the origin, but when you move it rotates around the y axis of the world and not the camera one. I guess I am not doing it right but I didn't find a way to do it that works anywhere.

Answer 1

I found a way to do it:

    Matrix.setIdentityM(mCurrentRotation, 0);
    Matrix.rotateM(mCurrentRotation, 0, mAngleY+mAngleX, 0.0f,1.0f, 0.0f);
    Matrix.rotateM(mCurrentRotation, 0, mAngleX, 0.0f,0.0f, 1.0f);
    mAngleX = 0.0f;
    mAngleY = 0.0f;

    Matrix.multiplyMM(mTemporaryMatrix, 0, mCurrentRotation, 0, mAccumulatedRotation, 0);

    System.arraycopy(mTemporaryMatrix, 0, mAccumulatedRotation, 0, 16);
    Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0);
    // multiply the rotation just for model*view
    Matrix.multiplyMM(mMVPMatrix, 0, mTemporaryMatrix, 0, mMVPMatrix, 0);
    //than add projection as usual
    Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0);

Where mTemporaryMatrix, mCurrentRotation,mAccumulatedRotation, are matrices to calculate total rotation, keep frame rotation and store the whole rotation of the camera, respectively. This solution works for rotation but it doesn't make the camera move in the direction it is pointing.