rendering speeds

[javatypo]

i made an lwjgl app, which isnt complete yet… but i made like a paddle and a “ball”, the ball moves around the screen and the paddle is controled with arrows. i have not yet added collision detection…

but i was wondering how to speed up the rendering process?

The ball sort of jerks around… and i am a newbie at this so any help would be cool…

heres my code if u want to c what im doing.

import org.lwjgl.*;
import org.lwjgl.opengl.*;
import org.lwjgl.input.*;

public class Test {
      
      static GL gl;
      static GLU glu;
      
      // for paddle      
      static float xPos;
      
      // for bouncing thing
      static int x,xspeed = 2;
      static int y,yspeed = 2;
      static int width;
      static int height;
      
      public static void main(String argv[]) throws Exception {
            // Choose a Display Mode
            DisplayMode[] modes = Display.getAvailableDisplayModes();
            for (int i=0; i<modes.length; i++) {
                  if (modes[i].width == 800 &&
                        modes[i].height == 600 &&
                        modes[i].bpp == 32) {
                              
                        Display.create(modes[i],true);
                        break;
                  }
            }
            
            xPos = Display.getWidth()/2;
            
            x = (Display.getWidth()-5)/2;
            y = (Display.getHeight()-5)/2;
            width = 10;
            height = 10;
            
            init();
            render();
      }
      
      public static void init() throws Exception {
            // init keyboard
            Keyboard.create();
            
            // init gl and glu
            gl = new GL();
            glu = new GLU(gl);
            gl.create();
            
            // set timers
            Sys.setTime(0);
            Sys.setProcessPriority(Sys.HIGH_PRIORITY);
            
            // init matrices
            gl.matrixMode(GL.PROJECTION);
            gl.loadIdentity();
            glu.ortho2D(0, Display.getWidth(), 0, Display.getHeight());
            gl.matrixMode(GL.MODELVIEW);
            gl.loadIdentity();
            gl.viewport(0,0, Display.getWidth(),Display.getHeight());
      }
      
      public static void render() {
            gl.clearColor(0,0,0,0);
            for (;;) {
                  gl.clear(GL.COLOR_BUFFER_BIT);
                  gl.pushMatrix();
                  gl.translatef(xPos, 10.0f, 0.0f);
                  gl.rotatef(5.0f,0.0f,1.0f,0.0f);
                  gl.begin(GL.QUADS);
                  {
                        gl.color3f(1.0f,0.0f,0.0f);
                        gl.vertex2i(-50,5);
                        gl.vertex2i(-50,30);
                        gl.color3f(0.0f,0.0f,1.0f);
                        gl.vertex2i(50,30);
                        gl.vertex2i(50,5);
                  }
                  gl.end();
                  gl.popMatrix();
                  
                  gl.pushMatrix();
                  gl.translatef(0, 0, 0);
                  gl.begin(GL.QUADS);
                  {
                        gl.color3f(0,149,219);
                        gl.vertex2i(x,y);
                        gl.vertex2i(x,(y+10));
                        gl.color3f(219,149,0);
                        gl.vertex2i((x+10),(y+10));
                        gl.vertex2i((x+10),y);
                  }
                  gl.end();
                  gl.popMatrix();
                        
                  gl.swapBuffers();
                  
                  updateBall();
                  checkKeys();
            }      
      }
      
      public static void updateBall() {
            if (((x+xspeed) > Display.getWidth())) xspeed *= -1;
            if (((x+xspeed) < 0)) xspeed *= -1;
            if (((y+yspeed) > Display.getHeight())) yspeed *= -1;
            if (((y+yspeed) < 0)) yspeed *= -1;
            
            x += xspeed;
            y += yspeed;
      }
            
      
      public static void checkKeys() {
            Keyboard.poll();
            
            if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)) {
                  Keyboard.destroy();
                  gl.destroy();
                  Display.destroy();
                  System.exit(0);
            }
            
            if (Keyboard.isKeyDown(Keyboard.KEY_LEFT)) {
                  if ((xPos-50.0f) - 5.0f < 0) return;
                  xPos-=5.0f;
            }
            
            if (Keyboard.isKeyDown(Keyboard.KEY_RIGHT)) {
                  if ((xPos+50.0f) + 5.0f > Display.getWidth()) return;
                  xPos+=5.0f;
            }
      }
}

[cfmdobbie]

Your bat is probably not going to change its geometry over the course of a game, so you could place it into a display list. If you change the ball drawing routine to translate to (x, y) first that could be in a display list too.

Aside from that, there’s nothing much more to optimize. At least, nothing that would have much effect. Run the game with -Xprof on the command line and pipe the output to a file. Where is the code spending most of it’s time?

A couple of comments:

You’ve probably fixed these already, but you’re got a do-nothing translate in there, and a couple of color3f calls that need their arguments fixed.

You’re using Display.getWidth/getHeight() several times per frame. I don’t know if the JVM can tell those settings aren’t going to change and optimise them, but you can just copy them out into private static final variables to help it along. Probably won’t affect the speed, but hey.

Your checkKeys() methods needs a few changes. At the moment, when one of the sanity checks fail it returns - you really want to just not execute the update instead.

[vrm]

I think you hit the 200 FPS and bnurn oall the CPU time, the jerk is prolly due to the garbage collector.

try to limit FPS :

      /** How many frames per second we want */
      public static final int DESIRED_FPS = 60;
       /** The duration of one frame, in seconds */
      public static final float FRAME_TIME = 1.0f / (float) DESIRED_FPS; 


// in the loop : 
    public boolean loop(float frameTime) {   
        /* if drawGLScene(...) fails, stop the loop */
            long then = Sys.getTime(); 
              

     call your render method here
            
            
        // in place of swaping the buffer by : _gl.swapBuffers();            
            if (!GL.WGL_EXT_swap_control) {
                  float elapsed = 0.0f;
                  frameTime = 0.0f;
                  do {
                        long now = Sys.getTime();
                        elapsed = (float)(now - then) / (float)Sys.getTimerResolution();
                        if (frameTime == 0.0f)
                              frameTime = elapsed;
                        if (elapsed < FRAME_TIME)
                        {
                              try{
                                    Thread.sleep(1);
                              }catch(InterruptedException ie)
                              {
                                    ie.printStackTrace();
                              }
                        }
                  }
                  while (elapsed < FRAME_TIME);
                _gl.swapBuffers();
          } else {
                 long now = Sys.getTime();
                 frameTime = (float)(now - then) / (float)Sys.getTimerResolution();
                 _gl.swapBuffers();
          } 

        input(frameTime);
        return _done;

    }

[oNyx]

limiting the fps would do the trick… well… it would look that way but the problem itself wont disapear this way.

the problem here is that u r using tick based animation (move x units to the left each frame) and that doesnt really work :]

take a look at the ported gametuturials.com tuturial i fixed recently u can find it (and tons of other nice tuts) at chman’s page:

http://chman-area.tuxfamily.org/

http://chman-area.tuxfamily.org/gt/GT10.ZIP

hf

edit:

mh… it still looks like the old one ._o

[oNyx]

ah well… here u go

import org.lwjgl.*;
import org.lwjgl.opengl.*;
import org.lwjgl.input.*;

public class Test {

 static GL gl;
 static GLU glu;

 // for paddle
 static float xPos, paddleSpeed;

 // for bouncing thing
 static float x,xspeed = 2;
 static float y,yspeed = 2;
 static int width;
 static int height;

 static float delta;
 static float ballUPS=150.0f;
 static float paddleUPS=350.0f;

 static long currentTime,frameTime;
 static float g_FrameInterval;

 public static void main(String argv[]) throws Exception {
  // Choose a Display Mode
  DisplayMode[] modes = Display.getAvailableDisplayModes();
  for (int i=0; i<modes.length; i++) {
   if (modes[i].width == 800 &&
    modes[i].height == 600 &&
    modes[i].bpp == 32) {

    Display.create(modes[i],true,"blub");
    break;
   }
  }

  xPos = Display.getWidth()/2;

  x = (Display.getWidth()-5)/2;
  y = (Display.getHeight()-5)/2;
  width = 10;
  height = 10;

  init();
  render();
 }

 public static void init() throws Exception {
  // init keyboard
  Keyboard.create();

  // init gl and glu
  gl = new GL();
  glu = new GLU(gl);
  gl.create();

  // set timers
  Sys.setTime(0);
  Sys.setProcessPriority(Sys.HIGH_PRIORITY);

  // init matrices
  gl.matrixMode(GL.PROJECTION);
  gl.loadIdentity();
  glu.ortho2D(0, Display.getWidth(), 0, Display.getHeight());
  gl.matrixMode(GL.MODELVIEW);
  gl.loadIdentity();
  gl.viewport(0,0, Display.getWidth(),Display.getHeight());

  gl.wglSwapIntervalEXT(0);
 }

 public static void render() {
  gl.clearColor(0,0,0,0);
  for (;;) {
   currentTime = Sys.getTime();
   g_FrameInterval = ((float)(currentTime - frameTime))/Sys.getTimerResolution();
   frameTime = currentTime;

   delta = ballUPS*g_FrameInterval;
   paddleSpeed = paddleUPS * g_FrameInterval;

   gl.clear(GL.COLOR_BUFFER_BIT);
   gl.pushMatrix();
   gl.translatef(xPos, 10.0f, 0.0f);
   gl.rotatef(5.0f,0.0f,1.0f,0.0f);
   gl.begin(GL.QUADS);
   {
    gl.color3f(1.0f,0.0f,0.0f);
    gl.vertex2i(-50,5);
    gl.vertex2i(-50,30);
    gl.color3f(0.0f,0.0f,1.0f);
    gl.vertex2i(50,30);
    gl.vertex2i(50,5);
   }
   gl.end();
   gl.popMatrix();

   gl.pushMatrix();
   gl.translatef(0, 0, 0);
   gl.begin(GL.QUADS);
   {
    gl.color3f(0,149,219);
    gl.vertex2f(x,y);
    gl.vertex2f(x,(y+10));
    gl.color3f(219,149,0);
    gl.vertex2f((x+10),(y+10));
    gl.vertex2f((x+10),y);
   }
   gl.end();
   gl.popMatrix();

   gl.swapBuffers();

   updateBall();
   checkKeys();
  }
 }

 public static void updateBall() {
  if (((x+xspeed) > Display.getWidth())) xspeed *= -1.0f;
  if (((x+xspeed) < 0)) xspeed *= -1.0f;
  if (((y+yspeed) > Display.getHeight())) yspeed *= -1.0f;
  if (((y+yspeed) < 0)) yspeed *= -1.0f;

  x += xspeed * delta;
  y += yspeed * delta;
 }


 public static void checkKeys() {
  Keyboard.poll();

  if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)) {
   Keyboard.destroy();
   gl.destroy();
   Display.destroy();
   System.exit(0);
  }

  if (Keyboard.isKeyDown(Keyboard.KEY_LEFT)) {
   if ((xPos-50.0f) - paddleSpeed < 0) return;
   xPos-=paddleSpeed;
  }

  if (Keyboard.isKeyDown(Keyboard.KEY_RIGHT)) {
   if ((xPos+50.0f) + paddleSpeed > Display.getWidth()) return;
   xPos+=paddleSpeed;
  }
 }
}

-> Display.create(modes[i],true,“blub”);

lwjgl 0.5… remove the “blub” part if u still use 0.4

-> gl.wglSwapIntervalEXT(0);

remove that line if your card doesnt support this extension or use 1 as argument (to enable vsync).

what i did isnt that complicated. instead of movin the stuff x units in each frame i check how many time elapsed since the last frame and multiply the time (in seconds) with the ups(units per second) value to get the distance wich it should have traveled

[Captain-Goatse]

In my terrain renderer, I found the problem was that I was running in a such a tight loop that the GC didn’t have time to do its work. What helped me, was that I caught one of the system threads and made it yield. Actually, you can do it with any thread. I’m pretty sure it is sort of dangerous to catch the system thread and force it to yield. Anyway, it is a possibility if you are absolutely afraid of creating a thread,