/* This shader was modified by Larry Gritz on 30 Mar 1998. 
     The original shader is KTlensflareV.sl written by Katsuaki HIRAMITSU. */

volume
KTlensflareV_lg
(
string     lens="on",fog="off";
float       distance=1500;
color      background=color(0.94,0.92,0.97);

/**   big flare paramater  **/
/*point       SunP=point(-0.6,0.6,3.464);*/
/*point       SunP=point "camera" (-0.42,0.73,3.464);*/
point       SunP_from=point "world" (-0.42,0.73,3.464),SunP_to=point "world" (0,0,0);
float       fov=60;
float
      ringS=0.3,ringL1=0.2,ringL2=0.4,ringL3=0.1,ringL4=0.1,ringL5=0.8,ringL6=0.15;
float       ringS_s=0.27,ringL1_s=0.13,ringL2_s=0.2;
float
      max_ring1=0.98,max_ring2=0.98,max_ring3=0.98,max_ring4=0.98,max_ring5=0.98,max_ring6=0.98;
float       max_ringS_s=0.6,max_ring1_s=0.98,max_ring2_s=0.98;
float
      max_mixS=0.1,max_mix1=0.025,max_mix2=0.025,max_mix3=0.05,max_mix4=0.05;
float       max_mix5=0.015,max_mix6=0.1;
float       max_mixS_s=0.3,max_mix1_s=0.1,max_mix2_s=0.05;
string
    typeS="clamp",type1="step",type2="step",type3="clamp",type4="clamp",type5="clamp",type6="clamp";
string     typeS_s="step",type1_s="step",type2_s="step";
color
     csS=color(1,0.25,0),cs1=color(0.74,1,0.87),cs2=color(1,1,0),cs3=color(1,1,0.5);
color      cs4=color(1,1,0.5),cs5=color(1,1,1),cs6=color(0.74,1,0.87);
color      csS_s=color(0,0.5,1),cs1_s=color(1,0.9,0.9),cs2_s=color(1,1,0);
float      roughness=-5;

/**   small flare paramater  **/
float       length1=0.02,length3=0.2,length4=0.05,length5=0.02,length6=0.04;
float       ring_sL1_1=0.005,ring_sL1_2=0.02,ring_sL2=0.15;
float       ring_sL3_1=0.01,ring_sL3_2=0.01;
float       ring_sL4_1=0.06,ring_sL4_2=0.05,ring_sL4_3=0.06;
float       ring_sL5_1=0.03,ring_sL5_2=0.005;
float
      ring_sL6_1=0.02,ring_sL6_2_1=0.03,ring_sL6_2_2=0.02,ring_sL6_3=0.02,ring_sL7=0.08;
float       max_ring_sL1_1=0.98,max_ring_sL1_2=0.98,max_ring_sL2=0.98;
float       max_ring_sL3_1=0.25,max_ring_sL3_2=0.25;
float       max_ring_sL4_1=0.98,max_ring_sL4_2=1,max_ring_sL4_3=0.98;
float       max_ring_sL5_1=0.8,max_ring_sL5_2=0.98;
float
      max_ring_sL6_1=0.9,max_ring_sL6_2_1=1,max_ring_sL6_2_2=0.9,max_ring_sL6_3=0.9,max_ring_sL7=0.9;
string     type_s1_1="step",type_s1_2="step",type_s2="clamp";
string     type_s3_1="step",type_s3_2="step";
string     type_s4_1="clamp",type_s4_2="specular",type_s4_3="clamp";
string     type_s5_1="step",type_s5_2="step";
string
    type_s6_1="step",type_s6_2_1="specular",type_s6_2_2="step",type_s6_3="step",type_s7="clamp";
float       max_mix_sL1_1=1.5,max_mix_sL1_2=0.69,max_mix_sL2=0.05;
float       max_mix_sL3_1=0.8,max_mix_sL3_2=0.5;
float       max_mix_sL4_1=0.05,max_mix_sL4_2=2,max_mix_sL4_3=0.05;
float       max_mix_sL5_1=0.69,max_mix_sL5_2=1.5;
float
      max_mix_sL6_1=0.4,max_mix_sL6_2_1=4,max_mix_sL6_2_2=0.4,max_mix_sL6_3=0.4,max_mix_sL7=0.05;
color
     cs_s1_1=color(1,1,1),cs_s1_2=color(0.74,1,0.87),cs_s2=color(0.74,0.9,1);
color      cs_s3_1=color(0.48,0.82,1),cs_s3_2=color(0.82,1,0);
color
     cs_s4_1=color(0.7,1,0),cs_s4_2=color(0.85,1,0.8),cs_s4_3=color(0.7,1,0);
color      cs_s5_1=color(1,0.9,0.72),cs_s5_2=color(1,1,1);
color
     cs_s6_1=color(0.6,0.82,1),cs_s6_2_1=color(0.8,0.85,1),cs_s6_2_2=color(0.6,0.82,1),cs_s6_3=color(0.6,0.82,1),cs_s7=color(0.92,1,0.92);
float       s_roughness=-5;

/*   highlight paramater  */
/*float       Highlight_roughness=10,Highlight_intensity=1.2;*/
float       Highlight_roughness=3,Highlight_intensity=1.05;
color      Highlightcolor=color(1,1,1);
float       lightscale=10,light_min=0.6,light_max=0.7;
float       light_roughness=12,light_intensity=0.4;
color      lightcolor=color(1,1,1)
)

{
float     fog_d;

point     norP,norSunP,norCenterP;
point     LensP1,LensP2,LensP3,LensP4,LensP5,LensP6;
point     DSunP,DLensP5;
point     SWP,SWSunP,SWLensP1,SWLensP2,SWLensP3,SWLensP4,SWLensP5,SWLensP6;
float     Pz,norSunPz;
float     judgeS;
float     r_unit,SWunit;
float     Dfloat;
color    ciS,opa_cs;
float     r,dis;

point
     SWsLensP1,SWsLensP2,SWsLensP3,SWsLensP4,SWsLensP5,SWsLensP6,SWsLensP7;
point
     SWsLensP1_1,SWsLensP1_2,SWsLensP3_1,SWsLensP3_2,SWsLensP4_1,SWsLensP4_2,SWsLensP4_3;
point      SWsLensP5_1,SWsLensP5_2,SWsLensP6_1,SWsLensP6_2,SWsLensP6_3;
point      moveP_unit;
float      moveL_unit;

float     Highlight;
point     LightP,norLightP;
float     PorM;
float     Cosin;
float     lightdis,lighttheta;

float judge,lens_judge;

point Z = vector "camera" (0,0,1);

if (fog=="on") {
     fog_d=1-exp(-length(I)/distance);
     Ci=Oi*mix(Ci,background,fog_d);
}


if (lens=="on") {

/*norP=normalize(P);*/
norP=normalize(I);

/* in the case of BMRT,
*norP=normalize(-I);
*/

/*norSunP=transform("world",SunP);
*norSunP=normalize(norSunP);
*norSunP=normalize(SunP);*/

norSunP=normalize(SunP_from-SunP_to);
norCenterP=Z;
norCenterP=normalize(norCenterP);

lens_judge=norCenterP.norSunP;
if (lens_judge>0) {


/*  flare  BEGIN  */
LensP1=reflect(-norSunP,norCenterP);
LensP1=normalize(reflect(-norCenterP,LensP1));
/*printf ("LensP1 = %p\n",LensP1);*/
LensP2=normalize(LensP1+norSunP);
LensP3=normalize(LensP1+LensP2);
LensP4=normalize(norSunP+LensP2);
LensP5=normalize(reflect(-norCenterP,norSunP));
DSunP=norSunP;
DLensP5=LensP5;
Dfloat=(1/3)/zcomp(DSunP);
DSunP=Dfloat*DSunP;
Dfloat=(2/3)/zcomp(DLensP5);
DLensP5=Dfloat*DLensP5;
LensP6=normalize(DSunP+DLensP5);

norSunPz=zcomp(norSunP);
SWunit=(1/norSunPz);
SWSunP=SWunit*norSunP;

SWLensP1=(1/zcomp(LensP1))*LensP1;
SWLensP2=(1/zcomp(LensP2))*LensP2;
SWLensP3=(1/zcomp(LensP3))*LensP3;
SWLensP4=(1/zcomp(LensP4))*LensP4;
SWLensP5=(1/zcomp(LensP5))*LensP5;
SWLensP6=(1/zcomp(LensP6))*LensP6;

/*Pz=zcomp(P);*/
Pz=zcomp(I);
SWunit=(1/Pz);
/*SWP=SWunit*P;*/
SWP=SWunit*I;

r_unit=tan(radians(fov/2));

judgeS=distance(SWP,SWSunP)/r_unit;

if (judgeS<ringS) {
    r=judgeS/ringS;
    dis=r;
    r=smoothstep(ringS_s/ringS,(((ringS-ringS_s)/3)+ringS_s)/ringS,dis)-smoothstep((ringS-((ringS-ringS_s)/3))/ringS,1,dis);
    r*=max_mixS;
    ciS=mix(Ci,csS,r);
    Ci=ciS;
}

#define DO_L(lens,ring,maxring,type,max_mix,cs) \
judge=distance(SWP,lens)/r_unit; \
if (judge<ring) { \
    r=judge/ring; \
    dis=r; \
    r=clamp(r,0,maxring); \
    r/=maxring; \
    if (type=="clamp") { \
             r=r-smoothstep(maxring,1,dis); \
     } \
     else if (type=="sine") { \
             r=sin(r*(PI/2)); \
             r=r-smoothstep(maxring,1,dis); \
     } \
     else if (type=="step") { \
             r=1-smoothstep(maxring,1,dis); \
     } \
     else if (type =="specular") { \
             r=pow(1+dis,roughness); \
     } \
     r*=max_mix; \
     Ci=mix(Ci,cs,r); \
}


DO_L (SWSunP, ringS_s, max_ringS_s, typeS_s, max_mixS_s, csS_s)
DO_L (SWLensP1, ringL1, max_ring1, type1, max_mix1, cs1)
DO_L (SWLensP1, ringL1_s, max_ring1_s, type1_s, max_mix1_s, cs1_s)
DO_L (SWLensP2, ringL2, max_ring2, type2, max_mix2, cs2)
DO_L (SWLensP2, ringL2_s, max_ring2_s, type2_s, max_mix2_s, cs2_s)
DO_L (SWLensP3, ringL3, max_ring3, type3, max_mix3, cs3)
DO_L (SWLensP4, ringL4, max_ring4, type4, max_mix4, cs4)
DO_L (SWLensP5, ringL5, max_ring5, type5, max_mix5, cs5)
DO_L (SWLensP6, ringL6, max_ring6, type6, max_mix6, cs6)

/*  flare END  */




/*  small flare  BEGIN  */
SWsLensP1=(SWSunP-(3/5*Z))*(5/2);
SWsLensP2=(1/4)*Z+(3/4)*SWSunP;
SWsLensP3=(3/4)*Z+(1/4)*SWSunP;
SWsLensP5=(Z-(1/2)*SWSunP)*2;
SWsLensP4=(1/2)*Z+(1/2)*SWsLensP5;
SWsLensP7=(Z-(2/3)*SWSunP)*3;
SWsLensP6=(1/4)*SWsLensP7+(3/4)*SWsLensP5;

/*moveP_unit=SWSunP-Z;*/
moveP_unit=Z-SWSunP;
moveL_unit=length(moveP_unit);
moveP_unit=normalize(moveP_unit);

SWsLensP1_1=SWsLensP1;
SWsLensP1_2=SWsLensP1+moveL_unit*length1*moveP_unit;
SWsLensP3_1=SWsLensP3;
SWsLensP3_2=SWsLensP3+moveL_unit*length3*moveP_unit;
SWsLensP4_1=SWsLensP4;
SWsLensP4_2=SWsLensP4+moveL_unit*length4*moveP_unit;
SWsLensP4_3=SWsLensP4+2*moveL_unit*length4*moveP_unit;
SWsLensP5_1=SWsLensP5;
SWsLensP5_2=SWsLensP5+moveL_unit*length5*moveP_unit;
SWsLensP6_1=SWsLensP6;
SWsLensP6_2=SWsLensP6+moveL_unit*length6*moveP_unit;
SWsLensP6_3=SWsLensP6+2*moveL_unit*length6*moveP_unit;


#define DO_SL(lens,ring,max_ring,type,max_mix,cs_s) \
judge = distance(SWP,lens)/r_unit; \
if (judge < ring) { \
    r=judge / ring; \
    dis=r; \
    r=clamp(r,0,max_ring); \
    r/=max_ring; \
    if (type =="clamp") { \
             r=r-smoothstep(max_ring,1,dis); \
     } \
     else if (type =="sine") { \
             r=sin(r*(PI/2)); \
             r=r-smoothstep(max_ring,1,dis); \
     } \
     else if (type =="step") { \
             r=1-smoothstep(max_ring,1,dis); \
     } \
     else if (type =="specular") { \
             r=pow(1+dis,s_roughness); \
     } \
     r*=max_mix ; \
     Ci =mix(Ci,cs_s,r); \
}

DO_SL(SWsLensP1_1,ring_sL1_1,max_ring_sL1_1,type_s1_1,max_mix_sL1_1,cs_s1_1)
DO_SL(SWsLensP1_2,ring_sL1_2,max_ring_sL1_2,type_s1_2,max_mix_sL1_2,cs_s1_2)
DO_SL(SWsLensP2,ring_sL2,max_ring_sL2,type_s2,max_mix_sL2,cs_s2)
DO_SL(SWsLensP3_1,ring_sL3_1,max_ring_sL3_1,type_s3_1,max_mix_sL3_1,cs_s3_1)
DO_SL(SWsLensP3_2,ring_sL3_2,max_ring_sL3_2,type_s3_2,max_mix_sL3_2,cs_s3_2)
DO_SL(SWsLensP4_1,ring_sL4_1,max_ring_sL4_1,type_s4_1,max_mix_sL4_1,cs_s4_1)
DO_SL(SWsLensP4_3,ring_sL4_3,max_ring_sL4_3,type_s4_3,max_mix_sL4_3,cs_s4_3)
DO_SL(SWsLensP4_2,ring_sL4_2,max_ring_sL4_2,type_s4_2,max_mix_sL4_2,cs_s4_2)
DO_SL(SWsLensP5_1,ring_sL5_1,max_ring_sL5_1,type_s5_1,max_mix_sL5_1,cs_s5_1)
DO_SL(SWsLensP5_2,ring_sL5_2,max_ring_sL5_2,type_s5_2,max_mix_sL5_2,cs_s5_2)
DO_SL(SWsLensP6_1,ring_sL6_1,max_ring_sL6_1,type_s6_1,max_mix_sL6_1,cs_s6_1)
DO_SL(SWsLensP6_3,ring_sL6_3,max_ring_sL6_3,type_s6_3,max_mix_sL6_3,cs_s6_3)
DO_SL(SWsLensP6_2,ring_sL6_2_1,max_ring_sL6_2_1,type_s6_2_1,max_mix_sL6_2_1,cs_s6_2_1)
DO_SL(SWsLensP6_2,ring_sL6_2_2,max_ring_sL6_2_2,type_s6_2_2,max_mix_sL6_2_2,cs_s6_2_2)
/*DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)

DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)
DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)
DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)
DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)
DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)*/
DO_SL(SWsLensP7,ring_sL7,max_ring_sL7,type_s7,max_mix_sL7,cs_s7)



/*  small flare  END  */



/*  highlight   BEGIN  */
Highlight=pow(judgeS+1,-(Highlight_roughness));
Highlight*=Highlight_intensity;
Ci=mix(Ci,Highlightcolor,Highlight);

LightP=SWP-SWSunP;
lightdis=length(LightP);
norLightP=normalize(LightP);
PorM=sign(ycomp(norLightP));
Cosin=norLightP.(vector "camera" (1,0,0));
lighttheta=PorM*acos(Cosin);
if (lighttheta<0) {
     lighttheta=PI-lighttheta;
}
lighttheta=noise(lightscale*lighttheta);
lighttheta=clamp(lighttheta,light_min,light_max);
lighttheta=(lighttheta-light_min)/(light_max-light_min);
lighttheta=lighttheta*pow(lightdis+1,-(light_roughness));
lighttheta*=light_intensity;

/*Oi=Oi;*/
Ci=mix(Ci,lightcolor,lighttheta);
/*Ci=Oi*mix(Ci,lightcolor,lighttheta);*/
/*  highlight   END  */


}

}

}