Colour depth for display

[Orangy Tang]

oNyx recently pointed out that Quix doesn't work fullscreen any more. :shock:  With a previous build it worked fine (after I remembered to check for 0Hz display modes as well).

Now I notice that the space invaders demo *does* work for him both windowed and fullscreen, which happens to use the bpp of the current display mode (the desktop I assume?). Other than that my code appears pretty much identical - I allow any bpp, but if two modes have identical size & refresh I favour ones with higher bpp.

In theory this should be ok, as if it fails on the 32 it'll keep trying others and eventually get to a 16bpp one. However it seems to create the display then fail to display anything. Is there anything I can do to detect such a situation?

[oNyx]

Hm. Well, I'm running 800x600x32 therefore I tried changing the resolution before running your game, but it doesn't help :/

If you paste your init code I can toy around with it until I get it running. So far I'm pretty clueless why it doesn't work.

[Orangy Tang]

Cheers, that'd be a good way of figuring this out.

This is a display test thingy I was going to have you try:

package quix;

import java.util.ArrayList;
import java.util.Collections;

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


/**
 * @author John Campbell
 */
public class DisplayTest
{

	
	public static void main(String[] args)
	{
		int method = 1;
		if (args.length == 1)
		{
			String arg1 = args[0];
			
			if (arg1.equals("1"))
				method = 1;
			
			if (arg1.equals("2"))
				method = 2;
			
			if (arg1.equals("3"))
				method = 3;
		}
		
		switch (method)
		{
			case 1:
				createMethodOne();		
				break;
			case 2:
				createMethodTwo();
				break;
			case 3:
				createMethodThree();			
				break;
			default:
				System.exit(-1);
		}
		
		run();
	}
	
	
	/** Identical to QuixGame. */
	private static void createMethodOne()
	{
		System.out.println("Create method ONE.");
		
		try
		{
			createFullscreenDisplay(true, false);
		}
		catch (LWJGLException e)
		{
			System.out.println("No suitable display modes found.");
			System.exit(-1);
		}
	}
	/** Like QuixGame, but limited to desktop colour depth */
	private static void createMethodTwo()
	{
		System.out.println("Create method TWO.");
		try
		{
			createFullscreenDisplay(true, true);
		}
		catch (LWJGLException e)
		{
			System.out.println("No suitable display modes found.");
			System.exit(-1);
		}
	}
	
	/** Copy-paste stright from QuixGame. */
	private static void createFullscreenDisplay(boolean fullscreen, boolean useDesktopColour) throws LWJGLException
	{
		System.out.println("Limiting selection to desktop colours:"+useDesktopColour);
		
		System.out.println("Attempting to create screen display...");
		
		if (fullscreen)
			System.out.println("Running in fullscreen mode.");
		else
			System.out.println("Running in windowed mode.");
		
		// Choose a display mode (monitor setting, dimensions&freq)
		DisplayMode[] modes = Display.getAvailableDisplayModes();
		
		// Find suitable
		ArrayList suitable = new ArrayList();
		for (int i=0; i<modes.length; i++)
		{
			DisplayMode dm = modes[i];
			if (dm.getWidth() == 800 && dm.getHeight() == 600)
			{
				if (dm.getFrequency() == 60 || dm.getFrequency() == 0)
				{
					if (useDesktopColour)
					{
						// Only add if a lower bpp.
						if (dm.getBitsPerPixel() <= Display.getDisplayMode().getBitsPerPixel())
							suitable.add(dm);
					}
					else
					{
						// Just add it.
						suitable.add(dm);
					}
				}
					
			}
		}
		
		if (suitable.size() == 0)
		{
			// No suitable display modes!
			System.out.println("No suitable display modes detected!");
			throw new LWJGLException("No suitable display modes found.");
		}
		
		Collections.sort(suitable, new DisplayModeComparator() );
		
		System.out.println("Suitable display modes by preference:");
		for (int i=0; i<suitable.size(); i++)
		{
			DisplayMode mode = (DisplayMode)suitable.get(i);
			System.out.println("\t"+mode);
		}
		
		DisplayMode usedMode = null;
		for (int i=0; i<suitable.size(); i++)
		{
			try
			{
				usedMode = (DisplayMode)suitable.get(i);
				System.out.println("Trying mode "+usedMode);
				Display.setDisplayMode( usedMode );
				break;
			}
			catch (Exception e)
			{
				// Failed to set display mode
				e.printStackTrace();
			}
		}
		
		
		try
		{
			System.out.println("Creating display");

			Display.setTitle("Quix!");
			Display.setFullscreen(fullscreen);
			Display.create();
			
			if (usedMode.getFrequency() == 60)
				Display.setVSyncEnabled(true);
		}
		catch (LWJGLException e1)
		{
			System.out.println("Could not create display.");
			e1.printStackTrace();
			throw e1;
		}
	}
	
	/** Snagged pretty much direct from the LWJGL space invaders example. */
	private static void createMethodThree()
	{
		System.out.println("Create method THREE.");
		
		// get modes
		DisplayMode[] dm = org.lwjgl.util.Display.getAvailableDisplayModes(
													800, 600, 800, 600, // Min & max res.
													-1, -1,				// Ignore bpp
													60, 60);			// Always 60Hz

		try
		{
			org.lwjgl.util.Display.setDisplayMode(dm, new String[] {
					"width=" + 800,
					"height=" + 600,
					"freq=" + 60,
					"bpp="
							+ org.lwjgl.opengl.Display.getDisplayMode()
									.getBitsPerPixel() });
			
			Display.setFullscreen(true);
			Display.create();
		}
		catch (Exception e)
		{
			System.out.println("Could not set display mode.");
			e.printStackTrace();
			System.exit(-1);
		}
	}
	
	
	
	private static void run()
	{
		boolean gameRunning = true;
		
		while (gameRunning)
		{
			Display.update();

			// The window is in the foreground, so we should play the game 
			update();
				
			// Stabilise the framerate if we haven't got vsync 
			Display.sync(60);

			
			if (Display.isCloseRequested() || Keyboard.isKeyDown(Keyboard.KEY_ESCAPE))
				gameRunning = false;
		}
		
		System.out.println("App.exit");
		Display.destroy();
		System.exit(0);
	}
	
	private static void update()
	{
		GL11.glBegin(GL11.GL_QUADS);
		{
			GL11.glColor3f(1f, 1f, 1f);
			
			int w = Display.getDisplayMode().getWidth();
			int h = Display.getDisplayMode().getHeight();
			
			float x = (float)w * 0.2f;
			float y = (float)h * 0.2f;
			float x2 = (float)w * 0.8f;
			float y2 = (float)h * 0.8f;
			
			GL11.glVertex2f(x, y);
			GL11.glVertex2f(x2, y);
			GL11.glVertex2f(x2, y2);
			GL11.glVertex2f(x, y2);
			
		}
		GL11.glEnd();
	}
}

You probably need the mode sorter as well:

package quix;

import java.util.Comparator;

import org.lwjgl.opengl.DisplayMode;

/**
 * @author John
 */
public class DisplayModeComparator implements Comparator
{
	public int compare(Object obj1, Object obj2)
	{
		if (obj1 instanceof DisplayMode && obj2 instanceof DisplayMode)
		{
			DisplayMode dm1 = (DisplayMode)obj1;
			DisplayMode dm2 = (DisplayMode)obj2;
			
			if (dm1.getFrequency() == dm2.getFrequency())
			{
				// Sort by bpp if freq identical
				if (dm1.getBitsPerPixel() == dm2.getBitsPerPixel())
					return 0;
				else if (dm1.getBitsPerPixel() > dm2.getBitsPerPixel())
					return -1;
				else
					return 1;
				
			}
			else if (dm1.getFrequency() > dm2.getFrequency())
			{
				return -1;
			}
			else 
			{
				return 1;
			}
			
			
		//	if (dm1.bpp > dm2.bpp)
		//		return 1;
		//	else
		//		return 2;
		}
		else
			return 0;
	}
}

Should be fairly self-explanitory. I wish I could give some hints as to what might be the problem but I'm at something of a loss. :oops:

[oNyx]

I tryed all 3 methods and none of em worked. :?

org.lwjgl.examples.Game doesn't work, too.

Ok. That's odd.

I have 3(!) different 0.92 builds here... and I tried em all...

filesize | fullscreen | windowed
880052 ok/ok
883274 ok/ok
835225 b0rked/ok

Nr3 is the one from Matzon (the same you got/used for Quix)... it seems to be slightly broken. With the other builds all 3 display setup methods work flawlessly.

[Orangy Tang]

I guess that points to a problem with the LWJGL build rather than my own code then. Great, now I can pass the blame. :wink: I guess Matzon or someone will know the differences between the builds.

[Matzon]

ehm. No.
The build I made was just from cvs - and *should* be no different from 0.92, except for the allocat method bug.

Apparently something else must also have changed...
This is a fresh dll, please try that:
http://matzon.dk/brian/lwjgl/builds/lwjgl.zip

[oNyx]

Using that dll with the two working builds results in:

UnsatisfiedLinkError: nCreateWindow

Using the dll with that broken lwjgl version works, but fullscreen is still broken there. Hm... :?