A quick search using...

    apt search Xlib.h

Turns up the package libx11-dev but you shouldn&#39;t need this for pure OpenGL programming. What tutorial are you using?

You can add Xlib.h to your system by running the following...

    sudo apt install libx11-dev

Presume he&#39;s using the tutorial from http://www.arcsynthesis.org/gltut/ along with premake4.3 :-) 

&gt; `sudo apt-get install libx11-dev` ................. for `X11/Xlib.h`  
&gt; `sudo apt-get install mesa-common-dev`........ for `GL/glx.h`  
&gt; `sudo apt-get install libglu1-mesa-dev` ..... for `GL/glu.h`  
&gt; `sudo apt-get install libxrandr-dev` ........... for `X11/extensions/Xrandr.h`  
&gt; `sudo apt-get install libxi-dev` ................... for `X11/extensions/XInput.h`  

After which I could build **glsdk_0.4.4** and examples without further issue.

Why not try `find /usr/include/X11 -name Xlib.h` 

If there is a hit, you have Xlib.h 

If not install it using `sudo apt-get install libx11-dev`

and you are good to go :)

I&#39;m new to iPhone and Mac programming (developed for Windows before), and I&#39;ve got a question:

How do I animate the `text` property of an `UILabel` between two numbers, e.g. from **5** to **80** in an Ease-Out style? Is it possible with `CoreAnimation`?
I have been searching on Google for an hour, but I haven&#39;t found anything solving my problem.
What I want: Animate the users money for a simple game. It doesn&#39;t look very nice when it just goes from **50** to **100** or something like that without animation.

Anyone having an idea how to do that?

Thanks!

Animate UILabel text between two numbers?

I have 4 DIV&#39;s right next to each other, and they&#39;re all centered in the middle of the screen. I have 2 words in each div, but I don&#39;t want them at the top, I want them to appear in the bottom right hand corner of the div. How can I do this?

Put text at bottom of div

I&#39;m trying to write a rather trivial program using open gl on linux, but at a compile time it says:


&gt; Compile thumb  : egl &lt;= cuberenderer.c
&gt; In file included from
&gt; /path/include/egl.h:36,
&gt;                  from /path/cuberenderer.c:7:
&gt; /path/include/eglplatform.h:89:22:
&gt; error: X11/Xlib.h: No such file or
&gt; directory
&gt; /path/include/eglplatform.h:90:23:
&gt; error: X11/Xutil.h: No such file or
&gt; directory

I&#39;m totally new to GL and have no idea what&#39;s wrong.

X11/Xlib.h not found in Ubuntu

I'm trying to write a rather trivial program using open gl on linux, but at a compile time it says:
> Compile thumb : egl &#x3C;= cuberenderer.c
> In file included from
> /path/include/egl.h:36,
> from /path/cuberenderer.c:7:
> /path/include/eglplatform.h:89:22:
> error: X11/Xlib.h: No such file or
> directory
> /path/include/eglplatform.h:90:23:
> error: X11/Xutil.h: No such file or
> directory
I'm totally new to GL and have no idea what's wrong.

Now I change my gnome-terminal&#39;s character encoding to &quot;GBK&quot; (default it is UTF-8), but how can I get the value(character encoding) in my Linux?

How to get terminal&#39;s Character Encoding

What would be your suggestion in order to create a single instance application, so that only one process is allowed to run at a time? File lock, mutex or what?

How to create a single instance application in C or C++

How can I do something like `command &gt; file` in a way that it appends to the file, instead of overwriting?

How to append the output to a file?

I am trying to connect minicom to a serial device that is connected via a USB-to-serial adapter. This is a PL2303 and from everything I&#39;ve read no additional drivers are required. The device is recognised as a PL2303.

I&#39;m a beginner at minicom. Is this the correct command to execute? Or do I need to configure something?

    $ sudo minicom --device /dev/ttyUSB0
    minicom: cannot open /dev/ttyUSB0: No such file or directory

    $ sudo lsusb -v

    Bus 002 Device 006: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
    Device Descriptor:
      bLength                18
      bDescriptorType         1

    $ tail /var/log/syslog  #then removed and attached the device.
    Mar 13 23:31:49 ubuntu kernel: [807996.786805] usb 2-1: pl2303 converter now attached to ttyUSB0
    Mar 13 23:34:44 ubuntu kernel: [808172.155129] usb 2-1: USB disconnect, address 7
    Mar 13 23:34:44 ubuntu kernel: [808172.156321] pl2303 ttyUSB0: pl2303 converter now disconnected from ttyUSB0
    Mar 13 23:34:44 ubuntu kernel: [808172.156374] pl2303 2-1:1.0: device disconnected
    Mar 13 23:34:52 ubuntu kernel: [808179.497856] usb 2-1: new full speed USB device using uhci_hcd and address 8
    Mar 13 23:34:52 ubuntu kernel: [808179.785845] pl2303 2-1:1.0: pl2303 converter detected
    Mar 13 23:34:52 ubuntu kernel: [808179.872309] usb 2-1: pl2303 converter now attached to ttyUSB0


How do I connect to a terminal to a serial-to-USB device on Ubuntu 10.10 (Maverick Meerkat)?

Using the `clear` command on the terminal only fools the user into thinking the screen has been cleared...you can still see output from the previous commands when you scroll using the mouse. This makes life difficult when you are drowning in a tsunami of text. 

Various solutions (escape code etc.) which can be found on the Internet are only variations of what the clear command already does.

So how do you clear the contents of a terminal in Linux for real?

Clear a terminal screen for real

How can I perform the following image processing tasks using OpenGL ES 2.0 shaders?

- Colorspace transform ( RGB/YUV/HSL/Lab ) 
- Swirling of the image 
- Converting to a sketch
- Converting to an oil painting

How can I do these image processing tasks using OpenGL ES 2.0 shaders?

I am currently investigating the possibility of rendering vector graphics from an SVG file using OpenGL and OpenGL ES. I intend to target Windows and Android. My ideal solution would be to have a minimal C library that generates a polygon triangulation from a given SVG file. This would then generate standard OpenGL or OpenGL ES calls, and use a display list or vbo for optimization when redrawing. I would simply draw a display list to draw the vector image after translating and rotating, allowing me to mix this with other OpenGL calls.

So far I see that the suggestions are to firstly use QT or Cairo. - This is not an option given that I wish to manage my own OpenGL context without bloated libraries (in the context of what I am trying to achieve). Nor is this suitable for Android.

Second option is to use libraries that render to a texture. While this might be ok for static vector graphics, it&#39;s not an efficient or feasible option for games where scaling and rotations occur frequently.

Thirdly there is the possibility of using OpenVG. There are some opensource implementations of the OpenVG specification (ShivaVG etc), but I am yet to find a library that is capable of generating the appropriate OpenVG calls from a given SVG file at runtime, and I can&#39;t see how to optimize this as we might wish to with a display list or vbo.

All three methods suffer limitations. I think the most promising option is using an OpenVG implementation if no other solution exists. So my question is, are there any libraries out there that do what I want, or close to what I want? If not, is there a good reason why not? And would it be better to attempt to do this from the ground up instead?

Rendering SVG with OpenGL (and OpenGL ES)

I need some help finding information (or an example) of how to use texture compression for Android. I have a lot of PNG&#39;s right now and I need to reduce the amount of memory they take up. I was looking at PVR compression but I can&#39;t figure out how to use this within OpenGL.

Could some point me in the right direction or offer some examples as I cannot find anything.


Android OpenGL Texture Compression

I have implemented some screens using libGDX that would obviously use the `Screen` class provided by the libGDX framework. However, the implementation for these screens works only with pre-defined screen sizes. For example, if the sprite was meant for a 640 x 480 size screen (4:3 Aspect ratio), it won&#39;t work as intended on other screen sizes because the sprites go par the screen boundaries and are not scaled to the screen size at all. Moreover, if simple scaling would have been provided by the libGDX, the issue I am facing would have still been there because that would cause the aspect ratio of the game screen to change.

After researching on internet, I came across a [blog/forum][1] that had discussed the same issue. I have implemented it and so far it is working fine. But I want to confirm whether this is the best option to achieve this or whether there are better alternatives. Below is the code to show how I am dealing with this legitimate problem.

FORUM LINK: http://www.java-gaming.org/index.php?topic=25685.new

	public class SplashScreen implements Screen {

	    // Aspect Ratio maintenance
	    private static final int VIRTUAL_WIDTH = 640;
	    private static final int VIRTUAL_HEIGHT = 480;
	    private static final float ASPECT_RATIO = (float) VIRTUAL_WIDTH / (float) VIRTUAL_HEIGHT;
	    
	    private Camera camera;
	    private Rectangle viewport;
	    // ------end------
	    
	    MainGame TempMainGame;
	    
	    public Texture splashScreen;
	    public TextureRegion splashScreenRegion;
	    public SpriteBatch splashScreenSprite;
	    
	    public SplashScreen(MainGame maingame) {
	        TempMainGame = maingame;
	    }

	    @Override
	    public void dispose() {
	        splashScreenSprite.dispose();
	        splashScreen.dispose();
	    }
	    
	    @Override
	    public void render(float arg0) {
	        //----Aspect Ratio maintenance
	        
	        // update camera
	        camera.update();
	        camera.apply(Gdx.gl10);
	        
	        // set viewport
	        Gdx.gl.glViewport((int) viewport.x, (int) viewport.y,
	        (int) viewport.width, (int) viewport.height);
	        
	        // clear previous frame
	        Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
	        
	        // DRAW EVERYTHING
	        //--maintenance end--
	        
	        splashScreenSprite.begin();
	        splashScreenSprite.disableBlending();
	        splashScreenSprite.draw(splashScreenRegion, 0, 0);
	        splashScreenSprite.end();
	    }
	    
	    @Override
	    public void resize(int width, int height) {
	        //--Aspect Ratio Maintenance--
	        // calculate new viewport
	        float aspectRatio = (float)width/(float)height;
	        float scale = 1f;
	        Vector2 crop = new Vector2(0f, 0f);
	        
	        if(aspectRatio &gt; ASPECT_RATIO) {
	            scale = (float) height / (float) VIRTUAL_HEIGHT;
	            crop.x = (width - VIRTUAL_WIDTH * scale) / 2f;
	        } else if(aspectRatio &lt; ASPECT_RATIO) {
	            scale = (float) width / (float) VIRTUAL_WIDTH;
	            crop.y = (height - VIRTUAL_HEIGHT * scale) / 2f;
	        } else {
	            scale = (float) width / (float) VIRTUAL_WIDTH;
	        }
	        
	        float w = (float) VIRTUAL_WIDTH * scale;
	        float h = (float) VIRTUAL_HEIGHT * scale;
	        viewport = new Rectangle(crop.x, crop.y, w, h);
	        //Maintenance ends here--
	    }
	    
	    @Override
	    public void show() {
	        camera = new OrthographicCamera(VIRTUAL_WIDTH, VIRTUAL_HEIGHT); //Aspect Ratio Maintenance
	        
	        splashScreen = new Texture(Gdx.files.internal(&quot;images/splashScreen.png&quot;));
	        splashScreenRegion = new TextureRegion(splashScreen, 0, 0, 640, 480);
	        splashScreenSprite = new SpriteBatch();
	        
	        if(Assets.load()) {
	            this.dispose();
	            TempMainGame.setScreen(TempMainGame.mainmenu);
	        }
	    }
	}

**UPDATE:** I recently came to know that libGDX has some of its own functionality to maintain aspect ratios which I would like to discuss here. While searching the aspect ratio issue across the internet, I came across several forums/developers who had this problem of &quot;How to maintain the aspect ratio on different screen sizes?&quot; One of the solutions that really worked for me was posted above.

Later on when I proceeded with implementing the `touchDown()` methods for the screen, I found that due to scaling on resize, the co-ordinates on which I had implemented `touchDown()` would change by a great amount. After working with some code to translate the co-ordinates in accordance with the screen resize, I reduced this amount to a great extent but I wasn&#39;t successful to maintain them with pin point accuracy. For example, if I had implemented `touchDown()` on a texture, resizing the screen would shift the touchListener on the texture region some pixels to the right or left, depending on the resize and this was obviously undesired.

Later on I came to know that the stage class has its own native functionality to maintain the aspect ratio (`boolean stretch = false`). Now that I have implemented my screen by using the stage class, the aspect ratio is maintained well by it. However on resize or different screen sizes, the black area that is generated always appears on the right side of the screen; that is the screen is not centered which makes it quite ugly if the black area is substantially large. 

Can any community member help me out to resolve this problem?


  [1]: http://www.java-gaming.org/index.php?topic=25685.new

How to deal with different aspect ratios in libGDX?

Is there any faster way to access the frame buffer than using glReadPixels? I would need read-only access to a small rectangular rendering area in the frame buffer to process the data further in CPU. Performance is important because I have to perform this operation repeatedly. I have searched the web and found some approach like using Pixel Buffer Object and glMapBuffer but it seems that OpenGL ES 2.0 does not support them. 

Faster alternative to glReadPixels in iPhone OpenGL ES 2.0

I am having some difficulty compiling a C++ program that I&#39;ve written.

This program is very simple and, to the best of my knowledge, conforms to all the rules set forth in the C++ Standard.  I&#39;ve read over the entirety of ISO/IEC 14882:2003 twice to be sure.

The program is as follows:

![enter image description here][1]

Here is the output I received when trying to compile this program with Visual C++ 2010:
    
    c:\dev&gt;cl /nologo helloworld.png
    cl : Command line warning D9024 : unrecognized source file type &#39;helloworld.png&#39;, object file assumed
    helloworld.png : fatal error LNK1107: invalid or corrupt file: cannot read at 0x5172

Dismayed, I tried g++ 4.5.2, but it was equally unhelpful:

    c:\dev&gt;g++ helloworld.png
    helloworld.png: file not recognized: File format not recognized
    collect2: ld returned 1 exit status

I figured that Clang (version 3.0 trunk 127530) must work, since it is so highly praised for its standards conformance.  Unfortunately, it didn&#39;t even give me one of its pretty, highlighted error messages:

    c:\dev&gt;clang++ helloworld.png
    helloworld.png: file not recognized: File format not recognized
    collect2: ld returned 1 exit status
    clang++: error: linker (via gcc) command failed with exit code 1 (use -v to see invocation)

To be honest, I don&#39;t really know what any of these error message mean.

Many other C++ programs have source files with a _.cpp_ extension, so I thought perhaps I needed to rename my file.  I changed its name to _helloworld.cpp_, but that didn&#39;t help.  I think there is a very serious bug in Clang because when I tried using it to compile the renamed program, it flipped out, printed &quot;84 warnings and 20 errors generated.&quot; and made my computer beep a lot!

What have I done wrong here?  Have I missed some critical part of the C++ Standard?  Or are all three compilers really just so broken that they can&#39;t compile this simple program?  

  [1]: http://i.stack.imgur.com/JQXWL.png

Why is this program erroneously rejected by three C++ compilers?

Under what situation is it possible for GCC to **not** throw an &quot;undefined reference&quot; link error message when trying to call made-up functions?

For example, a situation in which this C code is compiled and linked by GCC:

    void function()
    {
        made_up_function_name();
        return;
    }

...even though `made_up_function_name` is not present **anywhere** in the code (not headers, source files, declarations, nor any third party library).

Can that kind of code be accepted and compiled by GCC under certain conditions, without touching the actual code? If so, which?

Thanks.

EDIT: no previous declarations or mentions to `made_up_function_name` are present anywhere else. Meaning that a `grep -R` of the whole filesystem will **only** show that exact single line of code.

Can GCC not complain about undefined references?

I have a member function that is defined as follows:
    
    Value JSONDeserializer::ParseValue(TDR type, const json_string&amp; valueString);

When I compile the source, I get:

&gt; error: extra qualification &#39;JSONDeserializer::&#39; on member &#39;ParseValue&#39;

What is this? How do I remove this error?


extra qualification error in C++

I&#39;m getting the error:

&gt;Extension methods must be defined in a non-generic static class

On the line:

    public class LinqHelper

Here is the helper class, based on Mark Gavells code.  I&#39;m really confused as to what this error means as I am sure it was working fine when I left it on Friday!

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Linq.Expressions;
    using System.Reflection;
    
    /// &lt;summary&gt;
    /// Helper methods for link
    /// &lt;/summary&gt;
    public class LinqHelper
    {
        public static IOrderedQueryable&lt;T&gt; OrderBy&lt;T&gt;(this IQueryable&lt;T&gt; source, string property)
        {
            return ApplyOrder&lt;T&gt;(source, property, &quot;OrderBy&quot;);
        }
        public static IOrderedQueryable&lt;T&gt; OrderByDescending&lt;T&gt;(this IQueryable&lt;T&gt; source, string property)
        {
            return ApplyOrder&lt;T&gt;(source, property, &quot;OrderByDescending&quot;);
        }
        public static IOrderedQueryable&lt;T&gt; ThenBy&lt;T&gt;(this IOrderedQueryable&lt;T&gt; source, string property)
        {
            return ApplyOrder&lt;T&gt;(source, property, &quot;ThenBy&quot;);
        }
        public static IOrderedQueryable&lt;T&gt; ThenByDescending&lt;T&gt;(this IOrderedQueryable&lt;T&gt; source, string property)
        {
            return ApplyOrder&lt;T&gt;(source, property, &quot;ThenByDescending&quot;);
        }
        static IOrderedQueryable&lt;T&gt; ApplyOrder&lt;T&gt;(IQueryable&lt;T&gt; source, string property, string methodName)
        {
            string[] props = property.Split(&#39;.&#39;);
            Type type = typeof(T);
            ParameterExpression arg = Expression.Parameter(type, &quot;x&quot;);
            Expression expr = arg;
            foreach (string prop in props)
            {
                // use reflection (not ComponentModel) to mirror LINQ
                PropertyInfo pi = type.GetProperty(prop);
                expr = Expression.Property(expr, pi);
                type = pi.PropertyType;
            }
            Type delegateType = typeof(Func&lt;,&gt;).MakeGenericType(typeof(T), type);
            LambdaExpression lambda = Expression.Lambda(delegateType, expr, arg);
    
            object result = typeof(Queryable).GetMethods().Single(
                    method =&gt; method.Name == methodName
                            &amp;&amp; method.IsGenericMethodDefinition
                            &amp;&amp; method.GetGenericArguments().Length == 2
                            &amp;&amp; method.GetParameters().Length == 2)
                    .MakeGenericMethod(typeof(T), type)
                    .Invoke(null, new object[] { source, lambda });
            return (IOrderedQueryable&lt;T&gt;)result;
        }
    }



Extension methods must be defined in a non-generic static class

When compiling this code, I get the error &quot;initializer element is not a compile-time constant&quot;. Can anyone explain why?

    #import &quot;PreferencesController.h&quot;
    
    @implementation PreferencesController
    
    - (id)init
    {
        self = [super init];
        if (self) {
            // Initialization code here.
        }
        
        return self;
    }
    
    
    NSImage* imageSegment = [[NSImage alloc] initWithContentsOfFile:@&quot;/User/asd.jpg&quot;];//error here



Content Type	Original Author	Original Content on Stackoverflow
Question	Denys S.	View Question on Stackoverflow
Solution 1 - Linux	Andrew White	View Answer on Stackoverflow
Solution 2 - Linux	Bob Smith	View Answer on Stackoverflow
Solution 3 - Linux	Zohaib Amanzai	View Answer on Stackoverflow

X11/Xlib.h not found in Ubuntu

Linux Problem Overview

Linux Solutions

Solution 1 - Linux

Solution 2 - Linux

Solution 3 - Linux

Put text at bottom of div

Animate UILabel text between two numbers?

Attributions