title: GGX shader creation
body: <p>I'm trying to create a ggx shader but when I run it at BRDF Explorer the main page remains white. I'm trying to find my error but I can't.
  Can anybody help me?
  below is my file</p>
  
  <p>analytic</p>
  
  <pre><code>::begin parameters
  
  float baseColor 0.001 .2 .1
  
  float m 0.001 0.1 1.0 
  
  ::end parameters
  
  ::begin shader
  
      const float PI = 3.14;
  
  
      vec3 BRDF( vec3 N, vec3 V, vec3 L, float m, float baseColor)
          {
  
              vec3 H = normalize(V+L);
  
              float dotNL = clamp(dot(N,L), 0.0, 1.0);
              float dotLH = clamp(dot(L,H), 0.0, 1.0);
              float dotNH = clamp(dot(N,H), 0.0, 1.0);
  
              float DotNH2 = dotNH * dotNH;
              float m2 = m * m;
              float D =  m2 / (PI * pow(dotNH * dotNH * (m2 - 1) + 1, 2.0));
  
  
              float Fresnel(float baseColor, float l, float h)
          {
              return baseColor + ( 1 - baseColor ) * pow( 1 - (dotNH), 5);
          }
              float F = Fresnel(baseColor, dotNH);
  
  
              float ggx_visib(float dotNV, float m2) 
          { 
              return 1.0/(dotNV*(1.0-m2)+m2); 
          }                       
  
              float g1i =ggx_visib(m, dotLH);
              float g1o =ggx_visib(m, dotNV);
              float G = g1i * g1o;
  
  
  
          return D * G * F * (1.0 / (4.0 * dotNL * dotNV));
  
  
          }
  
  ::end shader
  </code></pre>