GPU-Accelerated Rendering of Unbounded Nonlinear Iterated Function System Fixed Points

Algorithm 2

vec4  nonlinear_inverse(vec2 destloc)

{  //  sum  up  IFS’s  density  at  destloc

 vec2  st=P(destloc);   //   (s,t)=T⁻¹

 vec2  srcloc=…;  //  V⁻¹(s,t)   see  Table 2

 return  f(+srcloc)   //  positive branch

   +  f(−srcloc);   //  negative branch

}

vec4  f(vec2 srcloc)   //  post-V coordinates

{  //  return  IFS’s  density  at  srcloc

 vec2  srctex=T(Minv(srcloc));   //  P⁻¹(M⁻¹)

 return  density(texture2D(src,srctex));

}