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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.apis.graphics.spritetext;
     18 
     19 import android.opengl.Matrix;
     20 
     21 import javax.microedition.khronos.opengles.GL10;
     22 
     23 /**
     24  * A utility that projects
     25  *
     26  */
     27 class Projector {
     28     public Projector() {
     29         mMVP = new float[16];
     30         mV = new float[4];
     31         mGrabber = new MatrixGrabber();
     32     }
     33 
     34     public void setCurrentView(int x, int y, int width, int height) {
     35         mX = x;
     36         mY = y;
     37         mViewWidth = width;
     38         mViewHeight = height;
     39     }
     40 
     41     public void project(float[] obj, int objOffset, float[] win, int winOffset) {
     42         if (!mMVPComputed) {
     43             Matrix.multiplyMM(mMVP, 0, mGrabber.mProjection, 0, mGrabber.mModelView, 0);
     44             mMVPComputed = true;
     45         }
     46 
     47         Matrix.multiplyMV(mV, 0, mMVP, 0, obj, objOffset);
     48 
     49         float rw = 1.0f / mV[3];
     50 
     51         win[winOffset] = mX + mViewWidth * (mV[0] * rw + 1.0f) * 0.5f;
     52         win[winOffset + 1] = mY + mViewHeight * (mV[1] * rw + 1.0f) * 0.5f;
     53         win[winOffset + 2] = (mV[2] * rw + 1.0f) * 0.5f;
     54     }
     55 
     56     /**
     57      * Get the current projection matrix. Has the side-effect of
     58      * setting current matrix mode to GL_PROJECTION
     59      * @param gl
     60      */
     61     public void getCurrentProjection(GL10 gl) {
     62         mGrabber.getCurrentProjection(gl);
     63         mMVPComputed = false;
     64     }
     65 
     66     /**
     67      * Get the current model view matrix. Has the side-effect of
     68      * setting current matrix mode to GL_MODELVIEW
     69      * @param gl
     70      */
     71     public void getCurrentModelView(GL10 gl) {
     72         mGrabber.getCurrentModelView(gl);
     73         mMVPComputed = false;
     74     }
     75 
     76     private MatrixGrabber mGrabber;
     77     private boolean mMVPComputed;
     78     private float[] mMVP;
     79     private float[] mV;
     80     private int mX;
     81     private int mY;
     82     private int mViewWidth;
     83     private int mViewHeight;
     84 }
     85