• 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
lemming77

Double and Float based fundamental types (vectors, matrices, etc.) implemented side by side?

6 posts in this topic

Hi,

As I'm sure is standard practice, I have written a library to implement types like vectors, matrices, and so on, and it all works quite nicely. However I have hit a hurdle.

Using D3D9 for graphics, that seems to like having it's data in the form of single precision floats. Which is fair enough. But I'm feeling the need to do some intense physics simulation using double precision. So what I really want is some means of implementing both without duplicating my entire library.

My current implementation lets me switch between Float and Double types before compiling by means of a typedef instruction. But this doesn't quite give me the solution I need, as I'm stuck choosing one over the other.

[source lang="cpp"]// The library is called Util. Not a great name, I know. Here's a small excerpt
// from Util.h. Define DOUBLE before compiling to use the double type.
// Otherwise, use the float type.

#ifdef DOUBLE
typedef double Real;
#define NAMESPACE Maths::Double
#else
typedef float Real;
#define NAMESPACE Maths
#endif

namespace Util {
namespace NAMESPACE {
struct Angle; // Euler angle
struct Matrix; // 4x4 Matrix
struct Quaternion;
struct Vector3;
}
}

// An excerpt from Vector3.h

namespace util {
namespace NAMESPACE {
// Vector3, 3D coordinates
struct Vector3 {
public:
Real x, y, z;

Vector3(); // x=0 y=0 z=0
Vector3(Real); // x=a y=a z=a
Vector3(Real, Real, Real); // x=a y=b z=c
/// ... Etc.
};
}[/source]

Can anyone recommend a means to implement both types into the same library? Preferably while duplicating as little source code as possible.

I'm using Visual C++ 2010 Express. Thanks [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img] Edited by lemming77
0

Share this post


Link to post
Share on other sites
As mentioned above, templates are just the right tool to use for your task.
In particular, class templates -- here's a tutorial with (plenty of) examples: http://cppannotations.sourceforge.net/cppannotations/html/cplusplus21.html#l451
0

Share this post


Link to post
Share on other sites
Templates do seem like a nice solution, although I can't help but wonder whether it's a bit overkill, since there's only the two versions of each I need. :P Are there any other ways I could do this for comparison?
0

Share this post


Link to post
Share on other sites
What's so overkill about it?
Basically, you replace 7 lines of code
[source lang="cpp"]
#ifdef DOUBLE
typedef double Real;
#define NAMESPACE Maths::Double
#else
typedef float Real;
#define NAMESPACE Maths
#endif
[/source]
with one* line of code
[source lang="cpp"]
template <typename Real>
[/source]
-- looks like less of an overkill to what it started as ;-)

* -- sure, you have to do that for each of { struct Angle; struct Matrix; struct Quaternion; struct Vector3; } -- that's still just 4 (< 7) lines of code, though :-)
And you don't need the separate-namespace-per-type complexity anymore, since, say Angle<float> and Angle<double> are unambiguously distinct types.

If for some reason you insist on the implementation that only lets you switch between floating-point types (and nothing else, refusing to compile for other kinds of types) you can easily achieve that with std::enable_if combined with std::is_floating_point:
http://en.cppreference.com/w/cpp/types/enable_if // see the "class A" example
http://en.cppreference.com/w/cpp/types/is_floating_point Edited by Matt-D
2

Share this post


Link to post
Share on other sites
I hadn't thought of it like that. I just assumed that templates came with a huge level of extra functionality which was going to waste.

I've done some experiments, and I think you're right. I really like how the template solution has worked out so far. I want to play around with it some more first, to better get to know it. But it's looking very likely that's the way I'll go!

Thank you for the help! :)
0

Share this post


Link to post
Share on other sites
I'm using bunch of typedefs in addition to templates:
[code]
typedef vector<float,2> vector2f;
typedef vector<float,3> vector3f;
typedef vector<float,4> vector4f;
typedef vector<double,2> vector2d;
typedef vector<double,3> vector3d;
typedef vector<double,4> vector4d;
[/code]
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