4 replies to this topic

[Jeason]

What is the biggest difference between D3DTOP_ADDSIGNED and D3DTOP_ADD?

When I take multitexture technology, I can get good effect by adding detail texture to base texture with D3DTOP_ADDSIGNED, but not with D3DTOP_ADD.

I can't comprehend it well.

[Jeason]

SOS!

[Madhed]

add signed has a -0.5 bias meaning the texture can brighten or darken the other texture.

IMHO you should ditch the fixed function pipeline which is outdated nowadays.

[Jeason]

Thank you! Madhed.


You are right. I just want to know the technologies which are introduced in the books, so i won't feel confused.

Yes, the detail map has to darken some pixel. So it needs to be signed.

[mhagain]

This is all covered in the SDK help file which should definitely be your first point of reference to supplement anything from books.

D3DTOP_ADDSIGNED
Add the components of the arguments with a - 0.5 bias, making the effective range of values from - 0.5 through 0.5.