Particle texture that has alpha in rgb channels

OpenGL OpenGL: Basic Coding
1

I’m trying to use particles with the alpha as the rgb channels in my program. Ranging from black (0,0,0) for transparent, to white (1,1,1) for opaque. Can I do this with a blend function or do I need to use a shader?
Thanks.

2

See glBlendFunc. Specifically, the SRC_COLOR blend functions. You can play with this here:

That said you could also write a shader, populate alpha and then use that to do your blending.