What's the difference....

[gdboling]

I'm new to LWJGL so bear with me.

I have 2 programs that are almost identicle except for on small section.  One of them displays the quad.  The other one does not.  

Here is the one that works..

package com.gthought.swing;

import org.lwjgl.DisplayMode;
import org.lwjgl.Display;
import org.lwjgl.input.Keyboard;
import org.lwjgl.opengl.Window;
import org.lwjgl.opengl.GL11;

public class OpenGLWindow
{
    public static void main(String[] args)
    {
        try
        {
            int mode = -1;
            DisplayMode[] modes = Display.getAvailableDisplayModes();
            System.out.println("Found " + modes.length + " display modes");
            for (int i = 0; i < modes.length; i++)
            {
                
                if (modes[i].width == 640 && modes[i].height == 640 && modes[i].bpp == 16)
               {
                   mode = i;
                }
                if (mode != -1)
                {
                    Display.setDisplayMode(modes[mode]);
                }
             }
        }
            catch(Exception e)
            {

            }
        try
        {
            Window.create("Test Window");
        }
        catch(Exception e)
        {

        }

        while(!Window.isCloseRequested())
        {
            Window.update();
            try
            {

                Thread.sleep(100);
            }
            catch(Exception ee)
            {

            }
            render();
            if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE))
            {
                break;
            }
        }

        Window.destroy();
    }

    private static void render()
    {
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);
		GL11.glPushMatrix();
		GL11.glTranslatef(Display.getWidth() / 2, Display.getHeight() / 2, 0.0f);
		GL11.glRotatef(45f, 0, 0, 1.0f);
		GL11.glBegin(GL11.GL_QUADS);
		GL11.glVertex2i(-50, -50);
		GL11.glVertex2i(50, -50);
		GL11.glVertex2i(50, 50);
		GL11.glVertex2i(-50, 50);
		GL11.glEnd();
		GL11.glPopMatrix();

    }
}

This puts the display in full screen mode and I can see my quad.  But I want to work in windowd mode, so I commented out 1 section and changed the Window.create() method like this..

package com.gthought.swing;

import org.lwjgl.DisplayMode;
import org.lwjgl.Display;
import org.lwjgl.input.Keyboard;
import org.lwjgl.opengl.Window;
import org.lwjgl.opengl.GL11;

public class OpenGLWindow
{
    public static void main(String[] args)
    {
        /*
        try
        {
            int mode = -1;
            DisplayMode[] modes = Display.getAvailableDisplayModes();
            System.out.println("Found " + modes.length + " display modes");
            for (int i = 0; i < modes.length; i++)
            {

                if (modes[i].width == 640 && modes[i].height == 640 && modes[i].bpp == 16)
               {
                   mode = i;
                }
                if (mode != -1)
                {
                    Display.setDisplayMode(modes[mode]);
                }
             }
        }
            catch(Exception e)
            {

            }
            */
        try
        {
            Window.create("Test Window", 50, 50, 640, 480, 16, 0, 0, 0, 0);
        }
        catch(Exception e)
        {

        }

        while(!Window.isCloseRequested())
        {
            Window.update();
            try
            {

                Thread.sleep(100);
            }
            catch(Exception ee)
            {

            }
            render();
            if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE))
            {
                break;
            }
        }

        Window.destroy();
    }

    private static void render()
    {
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);
		GL11.glPushMatrix();
		GL11.glTranslatef(Display.getWidth() / 2, Display.getHeight() / 2, 0.0f);
		GL11.glRotatef(45f, 0, 0, 1.0f);
		GL11.glBegin(GL11.GL_QUADS);
		GL11.glVertex2i(-50, -50);
		GL11.glVertex2i(50, -50);
		GL11.glVertex2i(50, 50);
		GL11.glVertex2i(-50, 50);
		GL11.glEnd();
		GL11.glPopMatrix();

    }
}

Now, I get the window to appear just fine.  But I can't see my quad.  Can someone tell me what I am doing wrong?

Thanks.

Gregg

[Fool Running]

I'm not sure without trying it, but it looks like your Window.update() needs to be called after you render in your loop, not before...

hope this helps  

[Fool Running]

something like this:

       while(!Window.isCloseRequested())
        {
            try
            {

                Thread.sleep(100);
            }
            catch(Exception ee)
            {

            }
            render();
            Window.update();

            if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE))
            {
                break;
            }
        }

I'll try it later when I get back from work  :lol:

[princec]

Actually - it doesn't matter where it gets called any more, as it's only called once per loop iteration.

Cas

[Fool Running]

I realized after I posted it that the Window.update() doesn't have to be at the bottom  :oops:  (and I call myself a programmer  :wink: )

anyways....

try changing

     GL11.glTranslatef(Display.getWidth() / 2, Display.getHeight() / 2, 0.0f);

to

     GL11.glTranslatef(Window.getWidth() / 2, Window.getHeight() / 2, 0.0f);

(I was trying this on version 0.8 so I had to play around with it, but I think that was the thing that made it work....  :roll:  )

[lunarknight]

You're code really helped me get started with LWJGL. You should submit it as a getting started code... or maybe make a few modifications and submit it to nehe tutorials!

Things your skeleton/base code taught me...
1)How to change resolution
2)How to go full screen
3)How to draw a polygon/triangle on the screen.

Thanks!~
LK

[lunarknight]

I guess what I don't understand is how to detect what Hz to use.
I want a 800x600 16bit full screen mode, but there's many different Hz values.

[princec]

There is now extremely groovy display mode selector utility class in org.lwjgl.util - have a look in the CVS.

Basically you pass it a bunch of criteria and it tries to pick the display mode that best satisfies your criteria.

Everyone should use it

Cas

[cfmdobbie]

Will do, as soon as it's in a downloadable distro!  Until then I'll use me own little class, presented here for your amusement:

package org.padcroft.clt.util;

import org.lwjgl.DisplayMode ;
import java.util.List ;
import java.util.ArrayList ;
import java.util.Iterator ;
import java.util.Collections ;
import java.util.Comparator ;
import java.lang.reflect.Field ;

/**
 * @author cfmdobbie
 */
public class DisplayModeFilter
{
	// Required DisplayMode settings
	private int width = -1 ;
	private int height = -1 ;
	private int bpp = -1 ;
	private int freq = -1 ;


	// List of sorts to apply to DisplayModes
	private List sortOrder = new ArrayList(10) ;

	// Private Comparator class to sort DisplayModes
	private static class DisplayModeFieldComparator
		implements Comparator
	{
		private final Field field ;
		private final boolean ascending ;

		private DisplayModeFieldComparator(final String fieldName, final boolean ascending)
		{
			try
			{
				field = DisplayMode.class.getField(fieldName) ;
			}
			catch(NoSuchFieldException e)
			{
				throw new AssertionError(e) ;
			}

			this.ascending = ascending ;
		}

		public int compare(Object e1, Object e2)
		{
			DisplayMode dm1 = (DisplayMode)e1 ;
			DisplayMode dm2 = (DisplayMode)e2 ;

			int f1, f2 ;

			try
			{
				f1 = field.getInt(dm1) ;
				f2 = field.getInt(dm2) ;
			}
			catch(IllegalAccessException e)
			{
				throw new AssertionError(e) ;
			}

			if(f1 < f2)
				return (ascending ? -1 : 1) ;
			else if(f1 > f2)
				return (ascending ? 1 : -1) ;
			else
				return 0 ;
		}
	}

	// Comparators
	private static final Comparator WIDTH_ASCENDING = new DisplayModeFieldComparator("width", true) ;
	private static final Comparator HEIGHT_ASCENDING = new DisplayModeFieldComparator("height", true) ;
	private static final Comparator BPP_ASCENDING = new DisplayModeFieldComparator("bpp", true) ;
	private static final Comparator FREQ_ASCENDING = new DisplayModeFieldComparator("freq", true) ;

	private static final Comparator WIDTH_DESCENDING = new DisplayModeFieldComparator("width", false) ;
	private static final Comparator HEIGHT_DESCENDING = new DisplayModeFieldComparator("height", false) ;
	private static final Comparator BPP_DESCENDING = new DisplayModeFieldComparator("bpp", false) ;
	private static final Comparator FREQ_DESCENDING = new DisplayModeFieldComparator("freq", false) ;

	// Constructor
	public DisplayModeFilter()
	{
	}

	// Property setters
	public DisplayModeFilter setWidth(final int width) { this.width = width ; return this ; }
	public DisplayModeFilter setHeight(final int height) { this.height = height ; return this ; }
	public DisplayModeFilter setBpp(final int bpp) { this.bpp = bpp ; return this ; }
	public DisplayModeFilter setFreq(final int freq) { this.freq = freq ; return this ; }

	// Sorting order functions
	public DisplayModeFilter sortByWidthAscending() { sortOrder.add(WIDTH_ASCENDING) ; return this ; }
	public DisplayModeFilter sortByHeightAscending() { sortOrder.add(HEIGHT_ASCENDING) ; return this ; }
	public DisplayModeFilter sortByBppAscending() { sortOrder.add(BPP_ASCENDING) ; return this ; }
	public DisplayModeFilter sortByFreqAscending() { sortOrder.add(FREQ_ASCENDING) ; return this ; }

	public DisplayModeFilter sortByWidthDescending() { sortOrder.add(WIDTH_DESCENDING) ; return this ; }
	public DisplayModeFilter sortByHeightDescending() { sortOrder.add(HEIGHT_DESCENDING) ; return this ; }
	public DisplayModeFilter sortByBppDescending() { sortOrder.add(BPP_DESCENDING) ; return this ; }
	public DisplayModeFilter sortByFreqDescending() { sortOrder.add(FREQ_DESCENDING) ; return this ; }

	// Filter method
	public DisplayMode[] filter(final DisplayMode[] inModes)
	{
		final List filteredModes = new ArrayList(inModes.length) ;

		for(int i = 0 ; i < inModes.length ; i++)
		{
			if(
				(width == -1 || width == inModes[i].width) &&
				(height == -1 || height == inModes[i].height) &&
				(bpp == -1 || bpp == inModes[i].bpp) &&
				(freq == -1 || freq == inModes[i].freq)
			)
			{
				filteredModes.add(inModes[i]) ;
			}
		}

		// Now sort filteredModes according to sort spec
		final Iterator i = sortOrder.iterator() ;
		while(i.hasNext())
		{
			final Comparator comparator = (Comparator)i.next() ;
			Collections.sort(filteredModes, comparator) ;
		}

		// Convert to array, and return
		DisplayMode[] outModes = (DisplayMode[])filteredModes.toArray(new DisplayMode[0]) ;

		return outModes ;
	}
}

Used like this:

DisplayModeFilter filter = new DisplayModeFilter();
filter.setWidth(1024).setHeight(768).setBpp(32);
filter.sortByFreqDescending();
DisplayMode[] modes = Display.getAvailableDisplayModes();
DisplayMode[] filtered = filter.filter(modes);

Rather overkill these days, but back when I first wrote it we were deciding things like alpha and depth buffers on display creation, as well!

[gdboling]

You're code really helped me get started with LWJGL. You should submit it as a getting started code... or maybe make a few modifications and submit it to nehe tutorials!

Things your skeleton/base code taught me...
1)How to change resolution
2)How to go full screen
3)How to draw a polygon/triangle on the screen.

Thanks!~
LK

For some reason I am not getting notified when this thread is updated and I have chosen that option.  Anyway, no problem.  Glad my misunderstanding could help someone.

[gdboling]

I realized after I posted it that the Window.update() doesn't have to be at the bottom  :oops:  (and I call myself a programmer  :wink: )

anyways....

try changing

     GL11.glTranslatef(Display.getWidth() / 2, Display.getHeight() / 2, 0.0f);

to

     GL11.glTranslatef(Window.getWidth() / 2, Window.getHeight() / 2, 0.0f);

(I was trying this on version 0.8 so I had to play around with it, but I think that was the thing that made it work....  :roll:  )

Yes, this seemed to do the trick.  Thanks.