matrixgrabber.java

android 例子中的确良ApiDemos。很有代表意义

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.graphics.spritetext;

import javax.microedition.khronos.opengles.GL10;

class MatrixGrabber {
    public MatrixGrabber() {
        mModelView = new float[16];
        mProjection = new float[16];
    }

    /**
     * Record the current modelView and projection matrix state.
     * Has the side effect of setting the current matrix state to GL_MODELVIEW
     * @param gl
     */
    public void getCurrentState(GL10 gl) {
        getCurrentProjection(gl);
        getCurrentModelView(gl);
    }

    /**
     * Record the current modelView matrix state. Has the side effect of
     * setting the current matrix state to GL_MODELVIEW
     * @param gl
     */
    public void getCurrentModelView(GL10 gl) {
        getMatrix(gl, GL10.GL_MODELVIEW, mModelView);
    }

    /**
     * Record the current projection matrix state. Has the side effect of
     * setting the current matrix state to GL_PROJECTION
     * @param gl
     */
    public void getCurrentProjection(GL10 gl) {
        getMatrix(gl, GL10.GL_PROJECTION, mProjection);
    }

    private void getMatrix(GL10 gl, int mode, float[] mat) {
        MatrixTrackingGL gl2 = (MatrixTrackingGL) gl;
        gl2.glMatrixMode(mode);
        gl2.getMatrix(mat, 0);
    }

    public float[] mModelView;
    public float[] mProjection;
}