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alpha channel in 32 bit surface (DD)

Graphics and GPU Programming Programming

Started by alexmoura November 16, 1999 05:27 AM

4 comments, last by alexmoura 24 years, 7 months ago

Gromit

144

November 14, 1999 11:05 AM

I am not exactly sure on this, however, I believe the bits go like RGBA not ARGB. Also Direct Draw doesn't suppot alpha channel blits yet, you would have to use D3D or write your own bitblt.

(someone could correct me on this as I am not positive.)

William Reiach - Human Extrodinaire

Marlene and Me

Josh Neta

122

November 14, 1999 06:35 PM

D3D uses ARGB textures.

Josh

alexmoura

450

Author

November 15, 1999 04:56 AM

DirectDraw in 32 bit seems to work in ARGB (well, at least ?RGB

. I am filling the bits myself...

Splat

122

November 15, 1999 03:21 PM

Grombit: Nope, you're right. DD doesn't support alpha-blending yet.

alexmoura: I'm pretty sure DD just ignores the high 8 bits in a 32-bit color. So, don't waste you're time wondering why your alpha-masked bitmap is coming in full color

- Splat

alexmoura

450

Author

November 16, 1999 05:27 AM

Hello. I've recentry been trying to blt 32 bit surfaces with alpha channel, to definetely eliminate non blt functions. Needless to say DD seems to ignore all my attempts. Could someone please tell me what do I need to do in order to get an alpha channel working? (with the alpha information in the pixels: ARGB) Thanks!

alexmoura

450

Author

November 16, 1999 05:27 AM

Well, just wanted to thank the answers. I've reverted to lock/unlock and value calculations on pointers, whenever it involves transparency... maybe in DX8?