Android Opengl es 写字 笔记

转载自：http://blog.csdn.net/li6185377/article/details/7255809

由于Opengl 本身是没有DrawString 这种函数的 所以我们要实现最简单的办法         字写在图片上  在把图片转为Texture 进行绘图

下面是我封装好的类

 package ljh.opengl.command;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Vector;
 import ljh.opengl.GLEx;
 import ljh.opengl.LColor;
 import ljh.opengl.LTexture;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Bitmap.Config;
 import android.graphics.Paint;

 public class GLFont {

          //要打印的字  字体大小  字的信息   最大宽度
     public static Bitmap getImage(String str, int fontsize, Paint paint,
             int maxWidth) {

         String[] text = StringFormat(str, maxWidth, fontsize);
         int[] count = getLinesMaxLength(text);
         Bitmap bitmap = Bitmap.createBitmap(count[0] * (fontsize / 2)
                 + count[1] * fontsize +5, (text.length) * fontsize,
                 Config.ARGB_8888);
         Canvas canvas = new Canvas(bitmap);
         paint.setTextSize(fontsize);
         for (int i = 0; i < text.length; i++) {
             canvas.drawText(text[i], 0, (i+1) * fontsize -3, paint);
         }
         return bitmap;
     }
         //具体的方法  还好我们前面实现了DrawTexture 我们这边就不用多写一次了
     public static void drawString(GLEx gl, String str, float x, float y,Paint paint,int maxWidth) {

         if(str==null||str.trim()=="")
             return;
         String key = str.trim().toLowerCase();
         LTexture texture = data.get(key);
         if(texture==null)
         {
             Bitmap bitmap = getImage(str, (int)paint.getTextSize(), paint, maxWidth);
             texture = new LTexture(bitmap);
             data.put(key, texture);
         }
         gl.drawTexture(texture, x, y);
     }
         //保存着写过的字的纹理 当渲染到一定次数 还没使用的将被销毁
     public static HashMap<String, LTexture> data = new HashMap<String, LTexture>();
         //保存要销毁的纹理
     private static ArrayList<String> UnusedList = new ArrayList<String>();

         //渲染线程没运行一次 次函数运行一次
         public static void update()
     {

          for(String key:data.keySet())
          {
              LTexture texture = data.get(key);
              if(texture.isUnused())
              {
                  UnusedList.add(key);
              }
              else
              {
                  texture.addUnused();
              }
          }
          for(String key:UnusedList)
          {
              GLEx.glex.delete(data.remove(key));
          }
          UnusedList.clear();
     }
     /**
      * 返回字数最多的那个行中中英文的数量
      *
      * @param lines
      * @return int[0] 英文的数量 int[1] 中文的数量
      */
     public static int[] getLinesMaxLength(String[] lines) {
         int max = 0, index = 0;
         for (int i = 0; i < lines.length; i++) {
             if (max < lines[i].getBytes().length) {
                 max = lines[i].getBytes().length;
                 index = i;
             }
         }
         int[] count = new int[2];
         for (int i = 0; i < lines[index].length(); i++) {
             if (lines[index].charAt(i) > 255) {
                 count[1]++;
             } else {
                 count[0]++;
             }
         }
         return count;
     }
         //对String 进行分段
     public static String[] StringFormat(String text, int maxWidth, int fontSize) {

         String[] result = null;
         Vector<String> tempR = new Vector<String>();
         int lines = 0;
         int len = text.length();
         int index0 = 0;
         int index1 = 0;
         boolean wrap;
         while (true) {
             int widthes = 0;
             wrap = false;
             for (index0 = index1; index1 < len; index1++) {
                 if (text.charAt(index1) == '\n') {
                     index1++;
                     wrap = true;
                     break;
                 }
                 widthes = fontSize + widthes;
                 if (widthes > maxWidth) {
                     break;
                 }
             }
             lines++;
             if (wrap) {
                 tempR.addElement(text.substring(index0, index1 - 1));
             } else {
                 tempR.addElement(text.substring(index0, index1));
             }
             if (index1 >= len) {
                 break;
             }
         }
         result = new String[lines];
         tempR.copyInto(result);
         return result;
     }

 }