I am applying a series of PostProcessing effects, and after the last effect, I have a black and white image. What I would like to do is store the rgb values of the frame before any effects are applied, and then access those values for use in an additional effect at the very end of the chain. Is this possible? If so, how would I go about it?

To phrase it another way, I would like to have a sort of tree structure for my post-processing effects. Perhaps one branch would apply a sobel filter, which would find edges but lose color information, while another branch would do a color shift. After both were done, I would merge the two results to create the final frame. Is this supported in some manner?

Just render it into a texture (stage_view.bmap = bmap_ptr;) which you then put back into the scene as a materialskin later on.

It almost seems like the camera stages could directly support what I want. If you could somehow have the views diverge into two branches, and then merge the branches back in the final stage...

Maybe I'm just talking out of my butt. Has anyone tried this, or seen something similar done?

why so complicated?
just do it as slin said. its really easy

Code:

---

BMAP* firstScreen;

[...]

camera.bmap = firstScreen;
camera.stage = greatPPview;

---

splitting is done as scorpion mentionned. joining by setting the split bmap as skin parameter for the joining material.

Thank you guys for your help, I really appreciate it. I think I'm almost there (I'm pretty new to shader programming). Here's my current process:

Code:

---

//bmap for the unprocessed screen
BMAP* firstScreen;
// a postprocessing view
VIEW* postprocessor1 = { material = mtl_pp_1; flags = CHILD | PROCESS_TARGET; }
...

//in main
camera.bmap = firstScreen;
camera.stage = postprocessor1;
mtl_pp_1.skin1 = firstScreen;

...

//in the .fx file
Texture mtlSkin1;
sampler2D mtl_sampler = sampler_state { texture = <mtlSkin1>; };

float4 pp_effect( float2 Tex : TEXCOORD0 ) : COLOR0 {
   float3 Color = tex2D(mtl_sampler, Tex.xy).xyz;
   return float4(Color,1.);
}

---

This should simply display the saved bmap, but instead gives an entirely black screen. I assume mtl_sampler is empty. Where might I be going wrong?

I found what I was missing

firstScreen = bmap_createblack(1024, 768, 24);

Thanks for your help guys, you're awesome.