1.if( abs(C.r - C.g) + abs(C.r-C.b) +abs(C.g - C.b) < F )
{
}
else
{
    C = C/D;
}
return C;

2.

float gray=0.21*C.x+0.72*C.y+0.072*C.z;

if( ( C.r < Min && (C.g > Max||C.b > Max) )
 || ( C.g < Min && (C.r > Max||C.b > Max) )
 || ( C.b < Min && (C.g > Max||C.r > Max) ) )
{
    C.xyz=lerp(float3(gray,gray,gray),C.xyz,D);
 }
return C;

            3.    tex.xyz=lerp(float3(0.5,0.5,0.5),tex.xyz,_contranst);//对比度