SDL File Loading When Running from Visual C++'s Debugger

I was testing some texture loading code on Visual C++ 2005 and 2008. The code compiled fine, but when I ran it from Visual C++'s debugger, it crashed every time. The code crashed because the program could not find my image file so it could not read the file and load the image. But the code ran file when I ran it from Windows Explorer. Why could my image file be found when I ran my program from Windows Explorer, but not from Visual C++'s debugger?

The reason was that Visual C++'s debugger uses a different working directory. Windows normally sets the working directory to the same directory as the executable file, which is where I had my image file. But Visual C++'s debugger sets the working directory to the directory containing the project file. Where is the project file? When you create a Visual C++ project, Visual C++ creates a folder that has the same name as the project name. Inside this folder is a second folder that has the same name as the project name. The project file resides in the second folder. The second folder is where the image file needed to be to debug my program. Moving my image file to the second folder fixed the crashing problem inside the Visual C++ debugger.

If you're using Visual C++ to write a game and you want to run the game inside the debugger, make sure your game's files are in the same directory as the project file.

Setting Up SDL with Visual C++ 2008 Express

Microsoft recently released Visual Studio Express. I wanted to see if my SDL setup instructions for Visual C++ 2005 Express (PDF) worked with Visual C++ 2008 Express so I installed Visual C++ 2008 Express and went through my instructions. The good news is Microsoft did not make a lot of changes in Visual C++ 2008 Express so most of the instructions still apply. There are two differences.

Visual C++ 2008 Express Contains the Win32 SDK

Unlike Visual C++ 2005 Express, Visual C++ 2008 Express ships with the Windows Platform SDK, also known as the Win32 SDK. Visual C++ 2008 Express's Win32 SDK support means you don't have to install the SDK separately, and you don't have to modify any files to get Win32 support.

 

If you're running Visual C++ 2008 Express, you can skip over the Installing the Windows Platform SDK, Updating the Visual C++ Properties File, and Updating the Application Wizard's Settings File sections in my instructions.

The Path to the Win32 SDK is Slightly Different

In the section Telling Visual C++ Where to Find Your SDL Headers and Libraries, I said the path to the Win32 SDK was the following path:

C:\Program Files\Microsoft Platform SDK

If you install Visual C++ 2008 Express, you'll find the Win32 SDK at the following path:

C:\Program Files\Microsoft SDKs\Windows\v6.0A

The v6.0A is the Win32 SDK version. If you're reading this in the future, the version number may change.

Changing SDL's Working Directory on Mac OS X

The Mac OS X version of SDL sets the working directory to the directory containing the application bundle. This default behavior makes loading images and sounds more difficult because the images and sounds most likely reside in the application bundle's Resources folder. What would be nice would be to set the working directory to the Resources folder. How do you do this?

You change the working directory by modifying the method -setupWorkingDirectory: in the file SDLMain.m. You'll want to change the code in SDLMain.m in SDL's Xcode templates so your changes take effect for any new SDL projects you create. Just to be safe, you should comment out the original code or save a copy of it so you can go back to the original if things go wrong. Enter the following code in the -setupWorkingDirectory: method:

NSString *resourcePath = [[NSBundle mainBundle] resourcePath];
[[NSFileManager defaultManager] 
changeCurrentDirectoryPath:resourcePath];

Thanks to Keith Bauer, aka OneSadCookie, for the source code to change the working directory.

Setting up Visual C++ on Windows Vista

I have instructions on setting up Visual C++ 2005 Express for SDL and OpenGL on my OpenGL 2D book site. I based those instructions on what I had to do to set up Visual C++ on my brother's computer running Windows XP. When I used the instructions to set up Visual C++ on my Windows Vista virtual machine, a major problem occurred. Visual C++ crashed every time I tried to add an existing file to a project. The crashes occurred because I hadn't installed the necessary service packs.

There are two service packs you must install for Visual C++ to work with Vista. The first is Visual C++ 2005 Express Service Pack 1. The second is Visual Studio 2005 Service Pack 1 Update for Windows Vista. Both of these service packs can be downloaded at Microsoft's developer site.

SDL 1.2.12

The latest version of SDL, 1.2.12, is available to download from the SDL website. Anyone using Mac OS X and supporting joysticks in their game should download the update because it fixes a joystick calibration bug. When starting a game, SDL would record joystick axis events when the joystick was not moved, causing movement in the game with no joystick movement. The only way to stop the unwanted movement was to move the joystick up, down, left, and right. The 1.2.12 update eliminates the unwanted movement, making joysticks work the way you would expect on Mac OS X.

Setting Up SDL for Eclipse on Mac OS X

I got an email from someone who was having trouble setting up SDL on Eclipse. I have never used Eclipse so I could not provide him much help. He eventually found a solution and emailed it to me so I could share it with you.

There are four things you have to do to get SDL working with Eclipse on Mac OS X in addition to what I outlined in my SDL tutorial. First, you must copy the files SDLMain.h and SDLMain.m to the same directory as your SDL program. My interpretation of this statement is if you create an Eclipse project and add your source code files to the project folder, you must also add SDLMain.h and SDLMain.m to the project folder.

Second, you must add the directory where your SDL headers reside to the Directories setting for the GCC C++ compiler. Your headers most likely reside in the following directory:

/Library/Frameworks/SDL.framework/Headers

Third, you must add linker flags for the Cocoa and SDL frameworks as well as the path to the SDLMain.m file.

-framework Cocoa
-framework SDL
/Path/To/YourProject/SDLMain.m

Fourth, you must change the following line of code in SDLMain.m:

#import "SDL.h"

to the following:

#include SDL/SDL.h

Put less than and greater than signs around the SDL/SDL.h. For some reason I can't get those characters to show up in the blog.