FPS：即幀 /秒(frames per second)的縮寫，也稱為幀速率。是指1秒鐘時間里刷新的圖片的幀數，也可以理解為圖形處理器每秒鐘能夠刷新幾次。如果具體到手機上就是指每秒鐘能夠 播放（或者錄制）多少格畫面。同時越高的幀速率可以得到更流暢、更逼真的動畫。每秒鐘幀數(fps)越多，所顯示的動作就會越流暢。
在絕大多數圖形程序中（以游戲類為典型），執行效率都以FPS作為評估標準。
由于目前JAVA方面缺少相關用例，故完成功能如下圖(在本機測試中，最大fps設定為500，實際達到FPS效率在IDE中280左右，單獨運行380左右，受系統配置等因素影響)：
代碼如下：
（請變更文件后綴為jar）
FPS相關操作代碼如下：
package org.test;
import java.text.DecimalFormat;
/**
* <p>Title: LoonFramework</p>
* <p>Description:</p>
* <p>Copyright: Copyright (c) 2007</p>
* <p>Company: LoonFramework</p>
* @author chenpeng
* @email：ceponline@yahoo.com.cn
* @version 0.1
*/
public class FPSListen {
//設定動畫的FPS楨數，此數值越高,動畫速度越快。
public static final int FPS = 500;
// 換算為運行周期
public static final long PERIOD = (long) (1.0 / FPS * 1000000000); // 單位: ns(納秒)
// FPS最大間隔時間，換算為1s = 10^9ns
public static long FPS_MAX_INTERVAL = 1000000000L; // 單位: ns
// 實際的FPS數值
private double nowFPS = 0.0;
// FPS累計用間距時間
private long interval = 0L; // in ns
private long time;
//運行楨累計
private long frameCount = 0;
//格式化小數位數
private DecimalFormat df = new DecimalFormat("0.0");
//開啟opengl
public void opengl(){
System.setProperty("sun.java2d.opengl", "True");
System.setProperty("sun.java2d.translaccel", "True");
}
/**
* 制造FPS數據
*
*/
public void makeFPS() {
frameCount++;
interval += PERIOD;
//當實際間隔符合時間時。
if (interval >= FPS_MAX_INTERVAL) {
//nanoTime()返回最準確的可用系統計時器的當前值，以毫微秒為單位
long timeNow = System.nanoTime();
// 獲得到目前為止的時間距離
long realTime = timeNow - time; // 單位: ns
//換算為實際的fps數值
nowFPS = ((double) frameCount / realTime) * FPS_MAX_INTERVAL;
//變更數值
frameCount = 0L;
interval = 0L;
time = timeNow;
}
}
public long getFrameCount() {
return frameCount;
}
public void setFrameCount(long frameCount) {
this.frameCount = frameCount;
}
public long getInterval() {
return interval;
}
public void setInterval(long interval) {
this.interval = interval;
}
public double getNowFPS() {
return nowFPS;
}
public void setNowFPS(double nowFPS) {
this.nowFPS = nowFPS;
}
public long getTime() {
return time;
}
public void setTime(long time) {
this.time = time;
}
public String getFPS(){
return df.format(nowFPS);
}
}
球體類代碼如下：
package org.test;
import java.awt.Color;
import java.awt.Graphics;
/**
* <p>Title: LoonFramework</p>
* <p>Description:</p>
* <p>Copyright: Copyright (c) 2007</p>
* <p>Company: LoonFramework</p>
* @author chenpeng
* @email：ceponline@yahoo.com.cn
* @version 0.1
*/
public class Ball {
private static final int SIZE = 10;
private int x, y;
protected int vx, vy;
public Ball(int x, int y, int vx, int vy) {
this.x = x;
this.y = y;
this.vx = vx;
this.vy = vy;
}
public void move() {
x += vx;
y += vy;
if (x < 0 || x > BallPanel.WIDTH - SIZE) {
vx = -vx;
}
if (y < 0 || y > BallPanel.HEIGHT - SIZE) {
vy = -vy;
}
}
public void draw(Graphics g) {
g.setColor(Color.RED);
g.fillOval(x, y, SIZE, SIZE);
}
}
FPS及球體處理用代碼如下：
package org.test;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Panel;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.util.Random;
/**
* <p>
* Title: LoonFramework
* </p>
* <p>
* Description:以JAVA獲取FPS用演示程序及隨機生成亂數球體。(更優化代碼內置于loonframework-game框架中)
* </p>
* <p>
* Copyright: Copyright (c) 2007
* </p>
* <p>
* Company: LoonFramework
* </p>
*
* @author chenpeng
* @email：ceponline@yahoo.com.cn
* @version 0.1
*/
public class BallPanel extends Panel implements Runnable {
/**
*
*/
private static final long serialVersionUID = 1L;
public static final int WIDTH = 360;
public static final int HEIGHT = 360;
// 設定最大球體數量
private static final int NUM_BALLS = 50;
// 定義球體數組
private Ball[] ball;
// 運行狀態
private volatile boolean running = false;
private Thread gameLoop;
// 緩存用圖形
private Graphics bg;
private Image screen = null;
// 生成隨機數
private Random rand;
// fps監聽
private FPSListen fps = null;
public BallPanel() {
setPreferredSize(new Dimension(WIDTH, HEIGHT));
screen = new BufferedImage(WIDTH, HEIGHT, 1);
bg = screen.getGraphics();
fps = new FPSListen();
//fps.opengl();
// 以當前毫秒生成隨機數
rand = new Random(System.currentTimeMillis());
ball = new Ball[NUM_BALLS];
// 初始化球體參數
for (int i = 0; i < NUM_BALLS; i++) {
int x = rand.nextInt(WIDTH);
int y = rand.nextInt(HEIGHT);
int vx = rand.nextInt(10);
int vy = rand.nextInt(10);
ball[i] = new Ball(x, y, vx, vy);
}
}
// 加入Notify
public void addNotify() {
super.addNotify();
// 判斷循環條件是否成立
if (gameLoop == null || !running) {
gameLoop = new Thread(this);
gameLoop.start();
}
}
/**
* 進行線程運作。
*/
public void run() {
long beforeTime, afterTime, timeDiff, sleepTime;
long overSleepTime = 0L;
int noDelays = 0;
// 獲得精確納秒時間
beforeTime = System.nanoTime();
fps.setTime(beforeTime);
running = true;
while (running) {
gameUpdate();
repaint();
afterTime = System.nanoTime();
timeDiff = afterTime - beforeTime;
// 換算間隔時間
sleepTime = (FPSListen.PERIOD - timeDiff) - overSleepTime;
if (sleepTime > 0) {
// 制造延遲
try {
Thread.sleep(sleepTime / 1000000L); // nano->ms
} catch (InterruptedException e) {
}
// 獲得延遲時間
overSleepTime = (System.nanoTime() - afterTime) - sleepTime;
} else {
// 重新計算
overSleepTime = 0L;
// 判斷noDelays值
if (++noDelays >= 16) {
Thread.yield(); // 令線程讓步
noDelays = 0;
}
}
// 重新獲得beforeTime
beforeTime = System.nanoTime();
// 制造FPS結果
fps.makeFPS();
}
}
/**
* 變更球體軌跡
*
*/
private void gameUpdate() {
for (int i = 0; i < NUM_BALLS; i++) {
ball[i].move();
}
}
/**
* 變更圖形
*/
public void update(Graphics g) {
paint(g);
}
/**
* 顯示圖形
*/
public void paint(Graphics g) {
// 設定背景為白色，并清空圖形
bg.setColor(Color.WHITE);
bg.fillRect(0, 0, WIDTH, HEIGHT);
// FPS數值顯示
bg.setColor(Color.BLUE);
bg.drawString("FPS: " + fps.getFPS(), 4, 16);
// 分別繪制相應球體
for (int i = 0; i < NUM_BALLS; i++) {
ball[i].draw(bg);
}
g.drawImage(screen, 0, 0, this);
g.dispose();
}
public static void main(String[] args) {
Frame frm = new Frame();
frm.setTitle("Java FPS速度測試(由Loonframework框架提供)");
frm.setSize(WIDTH, HEIGHT+20);
frm.setResizable(false);
frm.add(new BallPanel());
frm.setVisible(true);
frm.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
}
}
在絕大多數圖形程序中（以游戲類為典型），執行效率都以FPS作為評估標準。
由于目前JAVA方面缺少相關用例，故完成功能如下圖(在本機測試中，最大fps設定為500，實際達到FPS效率在IDE中280左右，單獨運行380左右，受系統配置等因素影響)：
代碼如下：
（請變更文件后綴為jar）FPS相關操作代碼如下：
package org.test;import java.text.DecimalFormat;/**
* <p>Title: LoonFramework</p> * <p>Description:</p> * <p>Copyright: Copyright (c) 2007</p> * <p>Company: LoonFramework</p> * @author chenpeng * @email：ceponline@yahoo.com.cn * @version 0.1 */public class FPSListen { //設定動畫的FPS楨數，此數值越高,動畫速度越快。 public static final int FPS = 500; // 換算為運行周期 public static final long PERIOD = (long) (1.0 / FPS * 1000000000); // 單位: ns(納秒) // FPS最大間隔時間，換算為1s = 10^9ns public static long FPS_MAX_INTERVAL = 1000000000L; // 單位: ns // 實際的FPS數值 private double nowFPS = 0.0; // FPS累計用間距時間 private long interval = 0L; // in ns private long time; //運行楨累計 private long frameCount = 0; //格式化小數位數 private DecimalFormat df = new DecimalFormat("0.0"); //開啟opengl public void opengl(){
System.setProperty("sun.java2d.opengl", "True"); System.setProperty("sun.java2d.translaccel", "True"); } /** * 制造FPS數據 * */ public void makeFPS() { frameCount++; interval += PERIOD; //當實際間隔符合時間時。 if (interval >= FPS_MAX_INTERVAL) { //nanoTime()返回最準確的可用系統計時器的當前值，以毫微秒為單位 long timeNow = System.nanoTime(); // 獲得到目前為止的時間距離 long realTime = timeNow - time; // 單位: ns //換算為實際的fps數值 nowFPS = ((double) frameCount / realTime) * FPS_MAX_INTERVAL; //變更數值 frameCount = 0L; interval = 0L; time = timeNow; } } public long getFrameCount() { return frameCount; } public void setFrameCount(long frameCount) { this.frameCount = frameCount; } public long getInterval() { return interval; } public void setInterval(long interval) { this.interval = interval; } public double getNowFPS() { return nowFPS; } public void setNowFPS(double nowFPS) { this.nowFPS = nowFPS; } public long getTime() { return time; } public void setTime(long time) { this.time = time; } public String getFPS(){ return df.format(nowFPS); }}球體類代碼如下：
package org.test;import java.awt.Color;import java.awt.Graphics;/** * <p>Title: LoonFramework</p> * <p>Description:</p> * <p>Copyright: Copyright (c) 2007</p> * <p>Company: LoonFramework</p> * @author chenpeng * @email：ceponline@yahoo.com.cn * @version 0.1 */public class Ball { private static final int SIZE = 10; private int x, y; protected int vx, vy; public Ball(int x, int y, int vx, int vy) { this.x = x; this.y = y; this.vx = vx; this.vy = vy; } public void move() { x += vx; y += vy; if (x < 0 || x > BallPanel.WIDTH - SIZE) { vx = -vx; } if (y < 0 || y > BallPanel.HEIGHT - SIZE) { vy = -vy; } } public void draw(Graphics g) { g.setColor(Color.RED); g.fillOval(x, y, SIZE, SIZE); } }FPS及球體處理用代碼如下：
package org.test;import java.awt.Color;import java.awt.Dimension;import java.awt.Frame;import java.awt.Graphics;import java.awt.Image;import java.awt.Panel;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import java.awt.image.BufferedImage;import java.util.Random;/** * <p> * Title: LoonFramework * </p> * <p> * Description:以JAVA獲取FPS用演示程序及隨機生成亂數球體。(更優化代碼內置于loonframework-game框架中) * </p> * <p> * Copyright: Copyright (c) 2007 * </p> * <p> * Company: LoonFramework * </p> * * @author chenpeng * @email：ceponline@yahoo.com.cn * @version 0.1 */public class BallPanel extends Panel implements Runnable { /** * */ private static final long serialVersionUID = 1L; public static final int WIDTH = 360; public static final int HEIGHT = 360; // 設定最大球體數量 private static final int NUM_BALLS = 50; // 定義球體數組 private Ball[] ball; // 運行狀態 private volatile boolean running = false; private Thread gameLoop; // 緩存用圖形 private Graphics bg; private Image screen = null; // 生成隨機數 private Random rand; // fps監聽 private FPSListen fps = null; public BallPanel() { setPreferredSize(new Dimension(WIDTH, HEIGHT)); screen = new BufferedImage(WIDTH, HEIGHT, 1); bg = screen.getGraphics(); fps = new FPSListen(); //fps.opengl(); // 以當前毫秒生成隨機數 rand = new Random(System.currentTimeMillis()); ball = new Ball[NUM_BALLS]; // 初始化球體參數 for (int i = 0; i < NUM_BALLS; i++) { int x = rand.nextInt(WIDTH); int y = rand.nextInt(HEIGHT); int vx = rand.nextInt(10); int vy = rand.nextInt(10); ball[i] = new Ball(x, y, vx, vy); } } // 加入Notify public void addNotify() { super.addNotify(); // 判斷循環條件是否成立 if (gameLoop == null || !running) { gameLoop = new Thread(this); gameLoop.start(); } } /** * 進行線程運作。 */ public void run() { long beforeTime, afterTime, timeDiff, sleepTime; long overSleepTime = 0L; int noDelays = 0; // 獲得精確納秒時間 beforeTime = System.nanoTime(); fps.setTime(beforeTime); running = true; while (running) { gameUpdate(); repaint(); afterTime = System.nanoTime(); timeDiff = afterTime - beforeTime; // 換算間隔時間 sleepTime = (FPSListen.PERIOD - timeDiff) - overSleepTime; if (sleepTime > 0) { // 制造延遲 try { Thread.sleep(sleepTime / 1000000L); // nano->ms } catch (InterruptedException e) { } // 獲得延遲時間 overSleepTime = (System.nanoTime() - afterTime) - sleepTime; } else { // 重新計算 overSleepTime = 0L; // 判斷noDelays值 if (++noDelays >= 16) { Thread.yield(); // 令線程讓步 noDelays = 0; } } // 重新獲得beforeTime beforeTime = System.nanoTime(); // 制造FPS結果 fps.makeFPS(); } } /** * 變更球體軌跡 * */ private void gameUpdate() { for (int i = 0; i < NUM_BALLS; i++) { ball[i].move(); } } /** * 變更圖形 */ public void update(Graphics g) { paint(g); } /** * 顯示圖形 */ public void paint(Graphics g) { // 設定背景為白色，并清空圖形 bg.setColor(Color.WHITE); bg.fillRect(0, 0, WIDTH, HEIGHT); // FPS數值顯示 bg.setColor(Color.BLUE); bg.drawString("FPS: " + fps.getFPS(), 4, 16); // 分別繪制相應球體 for (int i = 0; i < NUM_BALLS; i++) { ball[i].draw(bg); } g.drawImage(screen, 0, 0, this); g.dispose(); } public static void main(String[] args) { Frame frm = new Frame(); frm.setTitle("Java FPS速度測試(由Loonframework框架提供)"); frm.setSize(WIDTH, HEIGHT+20); frm.setResizable(false); frm.add(new BallPanel()); frm.setVisible(true); frm.addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e){ System.exit(0); } }); }}
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