Jump to content
  • Advertisement
Sign in to follow this  
Crafter

A question about D3DDECLUSAGE

This topic is 3560 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

There's a paragraph explains D3DDECLUSAGE_POSITION : ------------------------------------------------------------ Position data ranging from (-1,-1) to (1,1). Use D3DDECLUSAGE_POSITION with a usage index of 0 to specify untransformed position for fixed function vertex processing and the n-patch tessellator. Use D3DDECLUSAGE_POSITION with a usage index of 1 to specify untransformed position in the fixed function vertex shader for vertex tweening. ---------------------------------------------------------------------- In DirectX SDK (August 2007) what's the meaning of "Position data ranging from (-1,-1) to (1,1). " ? is the position data in World coordinate? and is it a 3D vector? how could it range from (-1,-1) to (1,1) ??

Share this post


Link to post
Share on other sites
Advertisement
That description seems entirely wrong. You can use any range of values, and typically, yes, they are 3D. Those limits may apply to usage index 1, when using the n-patch tessellator. I have no idea how that system works.

Positions are usually given in object space, which can be moved to world space with the world matrix. This allows you to use the same mesh in multiple locations in the world, or to have the object move without modifying the vertex data.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • 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!