Game Development and WinROTT

by Codewiz51 2. February 2010 18:48

In order to work on the current releases of WinROTT, you need to be familiar with GameDev.Net, and the circa 1999-2000 articles.  I've found the series Game Programming Genesis by Joseph Farrell to be informative.  Part IV : Introduction to DirectX is helpful for understanding older versions of DirectX and why developers may have followed a particular path that no longer makes sense.  You also need a solid understanding of COM when working with older versions of DirectX, the components tend to be most accessible via COM/ActiveX interfaces.

Good luck with your game programming.  And remember to visit GameDev for the latest development techniques.

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Changes to WinROTT

by Codewiz51 22. December 2009 09:34

Birger has made some nice changes to WinROTT, called WinROTTAPI.  I've downloaded the source and I am checking out how I might integrate Birger's changes into my branch of the game.  Many thanks to Birger for this work.

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Back to hobbyist programming...

by Codewiz51 2. February 2009 19:56

Finally, I can get back to the projects I love. I managed to complete the conversion of some software to work with Vista. The install package required quite a bit of modifcation as well. (UAC is definitely an abomination. There has to be a better way to implement it.)

There's a new WinROTT release 10.  I haven't made any progress converting to modern DirectX code. I am still trying to decipher the documentation and the scheme WinROTT uses to display graphics. To be honest, I am somewhat bewildered by all that is going on with DirectX. Maybe I'll start to click with it soon.

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An Interesting Warning in C and C++

by Codewiz51 8. January 2009 18:47

While working on WinROTT, I have come across a couple of warnings that may actually be serious bugs. One warning is C4309: 'initializing' : truncation of constant value.

This appears to be innocuous. But maybe it's not.

The following statement generates a C4309 warning:

signed char tx = 0x80;

The value of tx is -128 after this declaration and initalization occurs.

Let's assume this is followed by:

// value of tp is 128
unsigned char tp = 0x80;
bool tc = tx == tp;

What's the value of tc? You might think it is true. But in reality, the comparison is -128 == 128 which is false.

This may be a contrived example. But consider when you are working in a normal c++ program, where the type may be hidden:

// header file (.h)
#define SF_BAT      0x80

// Forward only linked list
typedef struct  statestruct
    byte                rotate;
    short               shapenum;    // a shapenum of -1 means get from ob->temp1
    short               tictime;
    void                (*think) (void *);
    signed char      condition;     // GH originally signed char
                                             // Caused 0x80 to be assigned as -128
    struct statestruct    *next;    // Link to next struct
} statetype;

// implementation file (.cpp)
// C4309 warning occurs here
statetype s_batblast4 = {FALSE,BATBLAST4,3,T_Projectile,SF_BAT,&s_batblast1};

// Here's where the execution problem occurs
// This comparison will always return false
if (s_batblast4->condition == SF_BAT)
    // Do something here

The moral is, don't ignore warnings. They may not be harmless. In this case, changing condition to unsigned char is the correct fix.

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WinROTT and the modexlib.cpp implementation

by Codewiz51 18. December 2008 08:06

I spent the evening studying the modexlib and tracing code execution paths. I need to understand how WinROTT is addressing video memory so that I can begin the translation to Direct3D 9. The learning curve is steep. I haven't looked at video memory layouts in 15 years and I have no recollection of ModeX VGA modes.

I am working on the idea that WinROTT will render to a texture which can then be bit blitted to video memory. I've got a rendering framework put together from several examples in the Direct3D 9 SDK, but the physical format WinROTT is using for video buffers is very different from the format needed for a texture.

At the moment, the task is well defined:

  1. Learn Direct3D 9
  2. Understand how WinROTT is addressing video memory (i.e. how is it drawing graphics?)
  3. Translate the existing WinROTT video routines to something Direct3D 9 can understand

I'm also still in the process of performing code cleanup and modernization. I'm working on some aspects of the code that can utilize threading to improve performance.

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Programming | WinROTT


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