Ambient light shader

[rob]

Hi Mario,

you used vector n = normalize(N); in the occlusion shader and then in the hemisphere color shader you altered vector n to equal vector n = normalize(ntransform( "space:world",N)); . why does this have to change from the original vector n = normalize(N);. Now want to combine the occlusion with grnd /sky colors of course now n has a different value.

Edited June 18, 2008 by rob

[Mario Marengo]

you used vector n = normalize(N); in the occlusion shader and then in the hemisphere color shader you altered vector n to equal vector n = normalize(ntransform( "space:world",N)); . why does this have to change from the original vector n = normalize(N);

It doesn't have to change. As I mentioned earlier, I just hijacked 'n' for my own evil purposes when computing the horizon stuff, without thinking, really. It was there, looking lonely; I was in a rush, so I used it. My bad. Apologies.

I'm tempted to just give you the two-line fix for that, but I get the feeling that doing so will just cause more confusion, so here's the whole horizon thing again, minus that goof.

#include <math.h>

#pragma label  htype "Horizon Type"
#pragma choice htype "lramp" "Linear Ramp"
#pragma choice htype "sramp" "Smooth Ramp"
#pragma choice htype "hard"  "Hard"
#pragma choice htype "soft"  "Soft"
#pragma label  hsoft "Horizon Softness"
#pragma range  hsoft 1e-4! 1!
#pragma disable hsoft htype "lramp"
#pragma disable hsoft htype "sramp"
#pragma disable hsoft htype "hard"

light rs_ambient_v02 (
         vector skycolor   = {1,0,0};
         vector grndcolor  = {0,0,1};
         string htype      = "soft";
         float  hsoft      = 0.2;
         float intensity   = 1;
         string env_map    = "Mandril.rat";
         string env_space  = "space:world";

   )
{
   vector n  = normalize(N);
   vector nw = ntransform("space:world",n); // <--- NEW WORLD-SPACE VERSION OF n

   float weight = 1.0 - acos(nw.y)/M_PI; // <--- WORLD-SPACE VERSION USED HERE
   float hw = weight;
   if(htype   == "sramp") {     // Smooth ramp
      hw = smooth(0,1,weight);
   } else if(htype   == "hard") {      // Hard edge
      hw = filterstep(0.5,weight);
   } else if(htype   == "soft") {      // Soft edge
      float halfinterval= clamp(hsoft*0.5,1e-4,0.5);
      hw = smooth(0.5-halfinterval,0.5+halfinterval,weight);
   }

   vector lightcolor = lerp(grndcolor,skycolor,hw);

   vector Cenv = 1;
   if(env_map!="") {
      string space = env_space=="" ? "space:world" : env_space;
      Cenv = environment(env_map,n,"envobject",space);
   }

   Cl = lightcolor*intensity*Cenv;
   L  = n; // <--- AS BEFORE
}

Now it leaves 'n' as it used to be, and uses a new variable 'nw' wherever a world-space version of 'n' is needed.

Untested... but it should work... I hope.

HTH.

[rob]

Hi Mario,

I have taken everything covered by you and expanded on the interface using the " pragma " operation and included custom icons and help. I guess the final thing to top off this shader would be to somehow implement a way of being able to export various parameters for use in compositing

As ever thanks so much for taking the time to expand everyones skills ..

Rob

rs_void_occlusion_hemis.otl

Edited June 19, 2008 by rob

[zasid]

It worked just great but now I m getting this error when I try to render it through mantra

Couldn't add library C:/Documents and Settings/ZOHAIB/ROBAO.otl

to Current HIP File.

Check that C:/Documents and Settings/ZOHAIB/ROBAO.otl is a valid operator type library.

Unable to get VEX code from:

opdef:/Shop/rs_void_occlusion_hemis

mantra: VEX error: Unable to load opdef:/Shop/rs_void_occlusion_hemis Path not found

Unable to get VEX code from:

opdef:/Shop/rs_void_occlusion_hemis

mantra: VEX error: Unable to load opdef:/Shop/rs_void_occlusion_hemis Path not found