• 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
texel3d

Use 16 bits values instead of 32 bits values

6 posts in this topic

Hi,

 

(Using DirectX 9)

Is it possible and usefull to use 16 bits values instead of 32 bits values for vertexbuffer and/or in hlsl shaders in order to have better performance and/or memory ressources ?

 

I can use D3DFMT_INDEX16 for my index buffer, can i have 16 bits values in by vertexbuffers ?

What about HLSL shaders ?

 

Thanks.

0

Share this post


Link to post
Share on other sites

Yes, you can use 16 bit values in your vertex buffer. And yes, this can be useful as it shrinks the size of your vertex buffer. This of course results in less memory usage, reduces bandwidth needed when sending vertices to the gpu, and also lets more vertices fit into the pre-transform vertex cache. This can result in the vertex shader being run fewer times. In some cases I've seen fairly significant performance improvements from "compressing" vertices like this.

 

As for using 16 bits floats for calculations in your shaders, I don't know enough to say whether this is still useful on today's GPUs.

Edited by phil_t
0

Share this post


Link to post
Share on other sites

Yes, it's possible, using D3DDECLTYPE_FLOAT16_2 or D3DDECLTYPE_FLOAT16_4 in your vertex declaration and the D3DXFLOAT16 struct (optionally with D3DXFloat32To16Array as a helper to set your data).  As well as reduced memory usage (which is not always the key determinant of performance) this can help with aligning odd-sized vertex structs.

0

Share this post


Link to post
Share on other sites

Thanks.

There is not a lot of documentation about D3DDECLTYPE_FLOAT16_2 and D3DDECLTYPE_FLOAT16_4.

Can i use 16 bits in CreateVertexBuffer() ? using which FVF flag ?

 

I can also read Microsoft documentation:

"The most important things with vertex performance is to use a 32-byte vertex, and to maintain good cache ordering."
http://msdn.microsoft.com/en-us/library/windows/desktop/bb173428%28v=vs.85%29.aspx

0

Share this post


Link to post
Share on other sites

Hi.

One thing to remember is the range the 16 byte is less then 32 bytes.

 

got me many years ago on my terrain 16 bytes runs out of range quickly.

0

Share this post


Link to post
Share on other sites

Thanks.

There is not a lot of documentation about D3DDECLTYPE_FLOAT16_2 and D3DDECLTYPE_FLOAT16_4.

Can i use 16 bits in CreateVertexBuffer() ? using which FVF flag ?

 

I can also read Microsoft documentation:

"The most important things with vertex performance is to use a 32-byte vertex, and to maintain good cache ordering."
http://msdn.microsoft.com/en-us/library/windows/desktop/bb173428%28v=vs.85%29.aspx

 

It's not possible to use 16-bit floats with FVF codes; you need to use shaders. Also be aware that converting from 32-bit float to 16-bit float isn't trivial since there's no built-in half type in C++. Also what ankhd said - generally you only want to use 16-bit floats for texture coordinates and maybe normals - elements with a limited range.

1

Share this post


Link to post
Share on other sites

 

Thanks.

There is not a lot of documentation about D3DDECLTYPE_FLOAT16_2 and D3DDECLTYPE_FLOAT16_4.

Can i use 16 bits in CreateVertexBuffer() ? using which FVF flag ?

 

I can also read Microsoft documentation:

"The most important things with vertex performance is to use a 32-byte vertex, and to maintain good cache ordering."
http://msdn.microsoft.com/en-us/library/windows/desktop/bb173428%28v=vs.85%29.aspx

 

It's not possible to use 16-bit floats with FVF codes; you need to use shaders. Also be aware that converting from 32-bit float to 16-bit float isn't trivial since there's no built-in half type in C++. Also what ankhd said - generally you only want to use 16-bit floats for texture coordinates and maybe normals - elements with a limited range.

 

 

The D3DXFLOAT16 type will handle the conversion for you.

 

Also, if the OP is talking about FVF codes in CreateVertexBuffer, but is using vertex declarations for actual drawing, then he's probably not aware that the FVF code in CreateVertexBuffer is only necessary if using the buffer as a destination buffer for the old IDirect3DDevice9::ProcessVertices call (broadly equivalent to compiled vertex arrays in OpenGL).  Otherwise FVF for CreateVertexBuffer can and should be set to 0.  See further: http://msdn.microsoft.com/en-us/library/windows/desktop/bb173428%28v=vs.85%29.aspx.

1

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