END OF AN ERA, FRACTALFORUMS.COM IS CONTINUED ON FRACTALFORUMS.ORG

munion(a,b,alpha){
   1/(1+alpha)*(a+b-sqrt(abs(a*a+b*b-2*alpha*a*b)))
}

mintersection(a,b,alpha){
   (0.25+0.5*alpha)/(1+alpha)*(a+b+sqrt(a*a+b*b-2*alpha*a*b))
}

#include "DE-Raytracer.frag"
uniform float R1; slider[0.1,1.1,2.3]
uniform float T; slider[0.1,1.1,2.3]
uniform float Dist; slider[0.1,1.1,2.3]

// some primitives from Quilez's lib
float maxcomp(vec3 a) { return  max(a.x,max(a.y,a.z)); }

float sdToBox( vec3 p, vec3 b )
{
  vec3  di = abs(p) - b;
  float mc = maxcomp(di);
  return min(mc,length(max(di,0.0)));
}

float sdSphere(vec3 p, float s) {  return length(p)-s; }

// Hart's blending function
float CR(float r, float R) {
float rR = clamp(r/R,0,1);
float rR2= rR*rR;
return 2.0*rR2*rR-3.0*rR2+1.0;
}

// The function proposed by Knighty.
uniform float alpha; slider[0,0,1]
float munion(float a, float b, float alpha){
  return 1.0/(1.0+alpha)*(a+b-sqrt(abs(a*a+b*b-2.0*alpha*a*b)));
}


float DE(vec3 p) {
float de1 = sdToBox(p-vec3(Dist,0.0,0.0),vec3(0.1));
float de2 = sdSphere(p-vec3(0.0,0.0,0.0),0.1);
        //return munion(de1,de2,alpha)-0.5;  // <-- for trying Knighty's approach
// Sum primitives
float sum = 0.0;
sum += CR(de1,R1);
sum += CR(de2,R1);
// ... and their radii
float radiSum = R1+R1;
return   (2.0/3.0)*(T - sum)*radiSum;
}