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#info Mandelbox Distance Estimator (Rrrola's version).
#include "DE-Raytracer.frag"
#include "MathUtils.frag"
#group RotXYBoxFold

/*
The distance estimator below was originalled devised by Buddhi.
This optimized version was created by Rrrola (Jan Kadlec), http://rrrola.wz.cz/

See this thread for more info: http://www.fractalforums.com/3d-fractal-generation/a-mandelbox-distance-estimate-formula/15/
*/

// Number of fractal iterations.
uniform int Iterations;  slider[0,17,300]
uniform int ColorIterations;  slider[0,3,300]

//uniform float MinRad2;  slider[0,0.25,2.0]

// Scale parameter. A perfect Menger is 3.0
uniform float Scale;  slider[-2.0,1.3,2.0]

//uniform float bailout;  slider[0,2.0,50]
uniform vec3 Fold; slider[(-1,-1,-1),(0,0,0),(1,1,1)]
uniform vec3 Julia; slider[(-1,-1,-1),(-0.5,-0.5,-0.5),(1,1,1)]
vec4 scale = vec4(Scale, Scale, Scale, abs(Scale));

// precomputed constants

uniform vec3 RotVector; slider[(0,0,0),(1,1,1),(1,1,1)]


// Scale parameter. A perfect Menger is 3.0
uniform float RotAngle; slider[0.00,0,180]

mat3 rot;


//float absScalem1 = abs(Scale - 1.0);
//float AbsScaleRaisedTo1mIters = pow(abs(Scale), float(1-Iterations));
float expsmoothing = 0;
float l = 0;
float s=Scale;

void init() {
		rot = rotationMatrix3(normalize(RotVector), RotAngle);
}


// Compute the distance from `pos` to the Fractal
float DE(vec3 pos) {
	vec3 p = pos, p0 = Julia;  // p.w is the distance estimate
	int i=0;
	s=Scale;
	for (i=0; i<Iterations; i++) {
		p.xy = clamp(p.xy, -Fold.xy, Fold.xy) * Fold.xy* 2.0 - p.xy; 
		p=p*Scale+p0;
		p*=rot;
		l=length(p);
		if (i<ColorIterations) orbitTrap = min(orbitTrap, abs(vec4(p.xyz,expsmoothing)));
	}
	return (l)*pow(abs(Scale), -float(i));
}

#preset Default
FOV = 0.684135
Eye = 4.27175,-1.46828,0.214248
Target = -13.2942,2.76206,-10.546
Up = -0.534436,-0.00990151,0.845151
AntiAlias = 3
AntiAliasBlur = 0.96296
Detail = -1.99269
DetailNormal = -2.42305
FudgeFactor = 0.91589
MaxRaySteps = 100
MaxRayStepsDiv = 8.25
BoundingSphere = 8.0723
Dither = 0.5
AO = 0,0,0,0.81967
Specular = 1.9167
SpecularExp = 16
SpotLight = 1,1,1,0.29348
SpotLightDir = 0.1,0.1
CamLight = 1,1,1,0.3871
Glow = 1,1,1,0
Fog = 0.33558
BaseColor = 1,1,1
OrbitStrength = 0.9703
X = 0.5,0.6,0.6,0.90552
Y = 1,0.6,0,0.65354
Z = 0.8,0.78,1,0.13386
R = 0.4,0.7,1,0.36508
BackgroundColor = 0.368627,0.462745,0.576471
GradientBackground = 0.64285
CycleColors = false
Cycles = 18.1816
Iterations = 19
ColorIterations = 7
Fold = 1,1,0.67832
Julia = -0.01408,0.23944,0.64788
RotVector = 1,0.85,1
RotAngle = 29.1888
Scale = 1.76808
#endpreset