Jump to content
  • Advertisement

Archived

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

FLaNK

RM vs IM

This topic is 6151 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I just bought a book ("The Awsome power of Direct3D/DirectX") in the hope of a bit of a DDraw resource.. ofourse its all about Direct3D so I thought I''d give that a shot. Unfortunately it almost solely covers Retained mode. I want to design a simple space shooter (fullscreen) game.. would it be easier to do this in RM or IM.. ie should I buy another book? Thanks

Share this post


Link to post
Share on other sites
Advertisement
Someone explain this concept of Retained mode/Immediate mode to me. I never really understood the difference.


--------------------

Never eat anything bigger than your own head.

Share this post


Link to post
Share on other sites
Retained mode was designed for RAD (Rapid Application Development). Immediate mode was designed for performance. RM fell down because it wasn''t any easier to write than IM (at least from DX5 onwards) so they got rid by DX7 and introduced a set of helper functions for IM called D3DX. D3DX is now tightly integrated into DX8 and is possibly (and this may cause controversy) easier to use than OpenGL now.

Neil

Share this post


Link to post
Share on other sites
Retained Mode was a high level scene graph API which sat on top of the much lower level immediate mode. My understanding is that it was called retained mode because it retained (or remembered) the objects that you had previously set up for it to draw in its own scene graph (an in-memory database of objects). That way you only had to tell it what the scene was made of, it stored the scene, and it worried about how to draw the scene each frame.

In immediate mode, however, you have to do a lot more work, describing the scene, remembering the scene (storing it in your own data structures), and telling DirectX how to draw the scene each frame yourself. Immediate mode generally proved more popular since it offered more flexibility, and gave those clever game programmers more low level control that they expected.

Eventually, Microsoft decided not to take Retained Mode any further. Retained Mode is however still part of the latest versions of DirectX, and should continue to be included since new versions of DirectX do include previous versions of API interfaces.

A few years back when Microsoft talked about the future of DirectX, then codenamed Fahrenheit, they said that it would be more OpenGL-like and support a powerful scene-graph (which I assumed would be the replacement of Retained Mode). So far, I don''t think that a powerful scene graph has been delivered, although Microsoft have wrapped Immediate Mode in a friendlier D3DX Utility library.

It is possible to develop a simple 3D space shooter in RM, I started this over 3 years ago and it still works with Windows 98/DirectX 8, Windows NT4(SP3), and Windows 2000:
http://www.abstractworlds.com/closeapproach
However if I was starting today, I''d probably use the D3DX Utility library.

Share this post


Link to post
Share on other sites

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!