• 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.
Sign in to follow this  
Followers 0
noatom

RandNumber problem

5 posts in this topic

So the following if is called every 0.04 seconds,

if( 1 == RangedRandDemo(1,20) ){

}

How is it possible that the above statement be true 20 times in a row,and sometimes,it never is?

My random function is:
int RangedRandDemo( int range_min, int range_max )
{
// Generate random numbers in the half-closed interval
// [range_min, range_max). In other words,
// range_min <= random number < range_max
srand( (unsigned)time( NULL ) );
int i;

int u = (double)rand() / (RAND_MAX + 1) * (range_max - range_min) + range_min;

return u;
}




Can you give me a better one?
0

Share this post


Link to post
Share on other sites
I have run into issues with the random number generator that did require calling srand again, but that is rare. Since it is a pseudo-random number generator, patterns can emerge that may be undesirable. If that happens, calling srand will resolve the issue. Chances are you'll never run into such an issue. That being said, alvaro is correct; srand should not be called every time rand is called.

[edit]
I should note that the RNG I was using at the time was limited to 16-bit signed integers.
0

Share this post


Link to post
Share on other sites
[quote name='iMalc' timestamp='1352104270' post='4997491']
Unless you intentionally wish to repeat a previous random sequence, calling srand again is undesireable.
Re-seeding causes the period of the PRNG to decrease because you jump to a new point within the sequence. That in itself reduces the amount of randomness.
If re-seeding made it seem less random then that was just dumb luck. It can just as easily make things worse.
The problem you had, with seeing a pattern in the output, is correctly solved by using a better PRNG.
[/quote]

I stand corrected. The PRNG was the Macintosh library function, Random. It gave a 16-bit signed output and it was pretty terrible. After a few thousand iterations, the "randomness" would converge to a small sequence of repeating numbers. The only way to resolve this was to reseed the RNG. I've been doing it this way ever since, save for when I switched to using Mersanine twister.

Thanks for the clarification.
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0