• 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
PureSnowX

Comparing pointers?

3 posts in this topic

Lets say I have a method that looks like this:
[CODE]
void handleFooChange( Foo* a, Foo* b)
{
if( a == NULL || b == NULL || a == b )
return;
if( a->deleteFoo() )
delete a;
a = b;
}
[/CODE]
Where Foo is an abstract class/interface that a and b inherits from. Can you compare two pointers like this ( See if they are pointing to the same memory adress i.e the same object )
0

Share this post


Link to post
Share on other sites
Yes, you can.

That code will correctly see if the two pointers both point to the same object.
0

Share this post


Link to post
Share on other sites
You can compare pointers and mentioned before but the last line in your function isn't doing anything.


I expect you wanted to be able to do something like this

[CODE]
Foo *newFoo = new Foo();

handleFooChange(oldFoo, newFoo);

// now oldFoo == newFoo
[/CODE]


but in reality oldFoo is unchanged because it retains its pointer to old object. When you passed oldFoo to the function the pointer is copied into another memory location so when you assign a = b, you change the value of a, but oldFoo is unaffected because it resides in a different place in the memory, even though oldFoo and a both point to the same object.


I don't know if you care about that or not but I thought I would mention that. You could fix this by making the parameters [url="http://markgodwin.blogspot.com/2009/08/c-reference-to-pointer.html"]references to pointers.[/url] Like this.

[CODE]
void handleFooChange( Foo *& a, Foo *& b)
{
if( a == NULL || b == NULL || a == b )
return;
if( a->deleteFoo() )
delete a;
a = b;
}
[/CODE]

Pointer logic be confusing at times so I would personally avoid this situation and try to come up with a solution that doesn't require double pointers, references to pointers, ect. I personally would refactor the code to look like this.

[CODE]
bool didFooChange( Foo* a, Foo* b)
{
if( a == NULL || b == NULL || a == b )
return false;
else
return true;
}

// then use it like this
if (didFooChange(oldFoo, newFoo))
{
delete oldFoo;
oldFoo = newFoo;
}

[/CODE]

That is some of my feedback. Edited by HappyCoder
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