Sprite

OpenGL OpenGL: Basic Coding
1

Hi,

I want to display a logo on my OpenGL program. My logo is a black BMP with the logo in white. You know what I mean I hope.
Example : a cross-hair in on a black BMP.

My question is :

How can I do to put the alpha value for black at 1.0 for only displaying my logo in white ?

Thanks in advance.

2

Hello

prompte your bitmap to RGBA, and for each pixel p, set p.alpha=1.0 if p is white, otherwise set to 0.0

well, if you want the WHITE to show through. change over 1.0 and 0.0 if you want the reverse.

cheers
jOHn

3

Maybe I’m wrong but if the texture is black with a white logo and you just want the logo to see trhu, u can set the glBlendFunc to GL_ONE_MINUS_SRC_COLOR.

It should work without any picture modifications.

rIO

4

glBlendFunc( GL_ONE, GL_ONE );

5

Gads, yes. I should have thought of that, too. <smacks forhead>