float sdSphere(vec3 p,float s){return length(p)-s;}
float udBox(vec3 p,vec3 b){return length(max(abs(p)-b,0.));}
float udRoundBox(vec3 p,vec3 b,float r){return length(max(abs(p)-b,0.))-r;}
float sdBox(vec3 p,vec3 b){vec3 d=abs(p)-b;return min(max(d.x,max(d.y,d.z)),0.)+length(max(d,0.));}
float sdTorus(vec3 p,vec2 t){vec2 q=vec2(length(p.xz)-t.x,p.y);return length(q)-t.y;}
float sdCylinder(vec3 p,vec3 c){return length(p.xz-c.xy)-c.z;}
float sdCone(vec3 p,vec2 c){/*c must be normalized*/float q=length(p.xy);return dot(c,vec2(q,p.z));}
float sdPlane(vec3 p,vec4 n){/*n must be normalized*/return dot(p,n.xyz)+n.w;}
float sdHexPrism(vec3 p,vec2 h){vec3 q=abs(p);return max(q.z-h.y,max((q.x*.866025+q.y*.5),q.y)-h.x);}
float sdTriPrism(vec3 p,vec2 h){vec3 q=abs(p);return max(q.z-h.y,max(q.x*.866025+p.y*.5,-p.y)-h.x*.5);}
float sdCapsule(vec3 p,vec3 a,vec3 b,float r){vec3 pa=p-a,ba=b-a;float h=clamp(dot(pa,ba)/dot(ba,ba),0.,1.);return length(pa-ba*h)-r;}
float sdCappedCylinder(vec3 p,vec2 h){vec2 d=abs(vec2(length(p.xz),p.y))-h;return min(max(d.x,d.y),0.)+length(max(d,0.));}
float sdCappedCone(in vec3 p,in vec3 c){
    vec2 q=vec2(length(p.xz),p.y);
    vec2 v=vec2(c.z*c.y/c.x,-c.z);
    vec2 w=v-q;
    vec2 vv=vec2(dot(v,v),v.x*v.x);
    vec2 qv=vec2(dot(v,w),v.x*w.x);
    vec2 d=max(qv,0.)*qv/vv;
    return sqrt(dot(w,w)-max(d.x,d.y))*sign(max(q.y*v.x-q.x*v.y,w.y));
}
float sdEllipsoid(in vec3 p,in vec3 r){return(length(p/r)-1.)*min(min(r.x,r.y),r.z);}
float udTriangle(vec3 p,vec3 a,vec3 b,vec3 c){
    vec3 ba=b-a;vec3 pa=p-a;
    vec3 cb=c-b;vec3 pb=p-b;
    vec3 ac=a-c;vec3 pc=p-c;
    vec3 nor=cross(ba,ac);
    return sqrt(
    (sign(dot(cross(ba,nor),pa))+
    sign(dot(cross(cb,nor),pb))+
    sign(dot(cross(ac,nor),pc))<2.)
    ?
    min(min(
    dot2(ba*clamp(dot(ba,pa)/dot2(ba),0.,1.)-pa),
    dot2(cb*clamp(dot(cb,pb)/dot2(cb),0.,1.)-pb)),
    dot2(ac*clamp(dot(ac,pc)/dot2(ac),0.,1.)-pc))
    :
    dot(nor,pa)*dot(nor,pa)/dot2(nor));
}
float udQuad(vec3 p,vec3 a,vec3 b,vec3 c,vec3 d){
    vec3 ba=b-a;vec3 pa=p-a;
    vec3 cb=c-b;vec3 pb=p-b;
    vec3 dc=d-c;vec3 pc=p-c;
    vec3 ad=a-d;vec3 pd=p-d;
    vec3 nor=cross(ba,ad);
    return sqrt(
    (sign(dot(cross(ba,nor),pa))+
    sign(dot(cross(cb,nor),pb))+
    sign(dot(cross(dc,nor),pc))+
    sign(dot(cross(ad,nor),pd))<3.)
    ?
    min(min(min(
    dot2(ba*clamp(dot(ba,pa)/dot2(ba),0.,1.)-pa),
    dot2(cb*clamp(dot(cb,pb)/dot2(cb),0.,1.)-pb)),
    dot2(dc*clamp(dot(dc,pc)/dot2(dc),0.,1.)-pc)),
    dot2(ad*clamp(dot(ad,pd)/dot2(ad),0.,1.)-pd))
    :
    dot(nor,pa)*dot(nor,pa)/dot2(nor));
}
float sdTorus82(vec3 p,vec2 t){vec2 q=vec2(length2(p.xz)-t.x,p.y);return length8(q)-t.y;}
float sdTorus88(vec3 p,vec2 t){vec2 q=vec2(length8(p.xz)-t.x,p.y);return length8(q)-t.y;}
float opU(float d1,float d2){return min(d1,d2);} //Union.
float opS(float d1,float d2){return max(-d1,d2);} //Subtraction.
float opI(float d1,float d2){return max(d1,d2);} //Intersection.
//float opRep(vec3 p,vec3 c){vec3 q=mod(p,c)-.5*c;return primitve(q);} //Repetition.
//vec3 opTx(vec3 p,mat4 m){vec3 q=invert(m)*p;return primitive(q);} //Rotation/Translation.
//float opScale(vec3 p,float s){return primitive(p/s)*s;} //Scale.
//float opDisplace(vec3 p){float d1=primitive(p);float d2=displacement(p);return d1+d2;} //Displacement.
//float opBlend(vec3 p){float d1=primitiveA(p);float d2=primitiveB(p);return smin(d1,d2);} //Blend.
//float opTwist(vec3 p){float c=cos(20.*p.y);float s=sin(20.*p.y);mat2 m=mat2(c,-s,s,c);vec3 q=vec3(m*p.xz,p.y);return primitive(q);}
//float opCheapBend(vec3 p){float c=cos(20.*p.y);float s=sin(20.*p.y);mat2 m=mat2(c,-s,s,c);vec3 q=vec3(m*p.xy,p.z);return primitive(q);}