make default shader/distance function more interesting

glsl/raymarching.js

}
`
  var fragmentShaderSrc = `
precision highp float;
  var fragmentShaderSrc = `precision highp float;
uniform vec2 iResolution;
uniform vec3 iMouse;
	return 1.0-float(stepsDone)/float(MaximumRaySteps);
}
float DistanceEstimator(vec3 pos) {
  return length(pos) - 1.0;
}
/*uniform int MaxIterations; //#slider[1,50,200]
const float bailout = 4.0;
const float power = 8.0;
	return 0.5 * r * log(r)/r_dz;
}*/
float sphere(vec3 pos) {
  return length(pos) - 1.0;
}
float pMod1(inout float p, float size) {
  float halfsize = size * 0.5;
  float c = floor((p + halfsize)/size);
  p = mod(p+halfsize, size)-halfsize;
  return c;
}
uniform vec3 offset; //#slider[(0.0,10.0,20.0),(0.0,10.0,20.0),(0.0,2.5,20.0)]
float DistanceEstimator(vec3 pos) {
  pMod1(pos.x, offset.x);
  pMod1(pos.y, offset.y);
  pMod1(pos.z, offset.z);
  return sphere(pos);
}
mat3 setCamera( in vec3 ro, in vec3 ta, float cr ) {
	vec3 cw = normalize(ta-ro);
	vec3 cp = vec3(sin(cr), cos(cr),0.0);
  return mat3( cu, cv, cw );
}
uniform vec3 origin; //#slider[(-10.0,1.0,10.0),(-10.0,2.0,10.0),(-10.0,-1.0,10.0)]
uniform vec3 angle; //#slider[(-3.0,0.0,3.0),(-3.0,0.0,3.0),(-3.0,0.0,3.0)]
uniform vec3 origin; //#slider[(-10.0,0.41,10.0),(-10.0,2.03,10.0),(-10.0,-1.34,10.0)]
uniform vec3 angle; //#slider[(-3.0,0.31,3.0),(-3.0,1.77,3.0),(-3.0,-0.18,3.0)]
uniform vec3 color; //#slider[(0.0, 1.0, 1.0),(0.0,0.0,1.0),(0.0,0.0,1.0)]
uniform float colorMix; //#slider[0.0,0.9,1.0]