Re: [Algorithms] Decals and deferred rendering

[Diogo de A. <dio...@ne...>]

Hi all,

I'm not sure I understood what you and Jeff are recommending, to be
honest...

Clarifying:

I start rendering to the G-Buffer... I have the buffers organized like this:

Rt0.xyz=normal (world space)
Rt0.w=depth (0..1 normalized)
Rt1.xyz=albedo
Rt1.w=ambient intensity
Rt2.x=specular intensity
Rt2.y=specular gloss
Rt2.z=diffuse intensity
Rt2.w=emissive intensity
Rt3.xyz=position (world space)
Rt3.w=unused

Let's imagine I have a maze... I render all walls to these buffers, and now
it's time to render the decals themselves.

With the G-Buffer still as the rendertarget, I draw the geometry that makes
up the decals (obtained through intersection of the world geometry with the
decal frustum)...
Now, the part I don't understand is how to achieve blending (which would be
sweet), without having the G-Buffer simultaneously as a render target and as
input texture (which I think is not allowed under the majority of the
videocards). If I could have that, I'd be able to do whatever I wanted in
the way of blending and such...
To be honest, now that I think about it, I'm not even seeing how I can make
a shader to render the decal in a way it only influences the albedo, even if
it is a simple replace, without using colorwrite masks (which I didn't want
to use because they makes me have to switch states). What I'm trying to
achieve (but may be impossible) is to have a "decal sheet", which has all
the decals, so that with a single draw I can get all decals up... not sure
if that's possible...

Thanks all,

Diogo