• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.

Archived

This topic is now archived and is closed to further replies.

nihlist

Input bool types to scripts and asBSTR construction

4 posts in this topic

Hi Andreas, I have been playing with AngelScript for a few days, trying to integrate it with a finite state machine character manager I am putting together. Its nice and compact, was easily wrapped in a C++ wrapper class that does the setup etc, perhaps I can share this if anyone is interested... Anyways, I am having trouble with bool data types, one of the first test cases I am putting together. Assume I have a class (apologies if this doesn't compile, I am typing this in directly, the state machine is somewhat more complex):
class Foo
{
  public:
     Foo();
     Foo(bool newData);
     ~Foo();
     bool getData();

  private:
     bool data;
};
  
With an implementation:
Foo::Foo()
{
  data = false;
}

Foo::Foo(bool newData)
{
  data = newData;
}

~Foo::Foo()
{
}

bool Foo::getData()
{
   return data;
}
  
Pretty useless by itself. If I register the class Foo in the engine and the getData() method as well and pass a pointer to a constructed Foo like such in a script method:
// Start Script

void test(Foo * foo)
{
  if (foo->getData())
  { 
     debug("foo->getData() was true");
  }
  else
  {
     debug("foo->getData() was false");
  }
}

// End Script
  
Where debug is a registered funtion that takes a asBSTR and pipes it to cout on the C++ side It always outputs: foo->getData() was true Even when I set the data value to false. I also tried: if (foo->getData() == true) ... and (foo->getData() == false) ... with no joy. I debugged this further and saw that your bool data type from the dll has: false = 0 true = 255 where MSVC++ 6.0 has false = 0 true = 1 I tried comparing the input bool with an int but the script engine trickily gave me a type conflict message. Thats as far as I got debugging it, any help would be appreciated. Additionally, does anyone know how to create a asBSTR in C++ code to send through to the engine, I know how to use the ones returned, am aware of the dll methods to allocate space for them but can find no examples on how to create a asBSTR from a const char * from the C++ side. Cheers, nihlist To understand recursion you must first understand recursion [edited by - nihlist on March 10, 2004 7:55:20 AM]
0

Share this post


Link to post
Share on other sites
I did some debugging, and as it happens you stumbled upon a bug or perhaps a design flaw in AngelScript. MSVC C++ treats the bool type as a 1 byte boolean type, whereas AngelScript treats it as a 4 byte boolean type. When C++ returns the boolean value it does so in the lower 8 bits of EAX, leaving the higher 24 bits with their previous value, meaning that EAX will almost always be different from 0.

Fortunately this is quite easy to fix (changing the AngelScript type to 1 byte as well, should fix the problem), and the next release will have this fix.

In the sample code, available from the angelscript page, there are some functions that return bstrs to the script. Example:

asBSTR bstrFormatInt(int number)
{
acCString str;
str.Format("%d", number);

// We must allocate a new bstr that the script engine will free afterwards
asBSTR bstr = asBStrAlloc(str.GetLength());

memcpy(bstr, str, str.GetLength());

return bstr;
}

Remember that if you receive a bstr by value in the parameters you are responsible to releasing the memory. Therefore I recommend that you always declare your functions to receive bstrs by reference, it would also avoid an internal copy of the bstr.

www.AngelCode.com - game development and more...
AngelScript - free scripting library
0

Share this post


Link to post
Share on other sites
Hi Andreas,

Thanks for the quick feedback. I am happy for a credit for this one, my name is Josh Passenger.

nihlist

To understand recursion you must first understand recursion
0

Share this post


Link to post
Share on other sites
Oh and thanks for the tips on the asBSTR, I hunted high and low but must have missed this one,

nihlist

To understand recursion you must first understand recursion
0

Share this post


Link to post
Share on other sites