Refracted Apollonian

April 19, 2021, 06:04:01 PM

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$Refracted Apollonian$

Refracted Apollonian

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Description: Experiment with the refract() function

In the ray marching routine:
1. Determine ray direction for the current pixel is usual.
2. calculate the pixel to camera distance, pixel position and normal as usual.
3. Memorize this pixel position.
4. Update the ray direction: direction = refract(direction,normal, param1);
5. Move the camera to pixel position + direction * 3 // offset the position to ensure the new ray is walked a little
6. walk ray in new refracted direction to new pixel position
7. final position = mix(original pixel position, new pixel position, param2);

In the attached image I used the the Apollonian algorithm with
param1 (amount of refraction) = 1.047
param2 (position mixer ratio) = 0.92
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Apollonian algorithm presented here: https://www.shadertoy.com/view/4ds3zn

CPU ---------------------

control.maxSteps = 5
control.multiplier = 21.400024
control.foam = 0.6999993
control.foam2 = 2.3999999
control.bend = 0.0211

// GPU -------------------

float DE(float3 pos,device Control &control,thread float4 &orbitTrap) {
float k,t = control.foam2 + 0.25 * cos(control.bend * PI * control.multiplier * (pos.z - pos.x));
float scale = 1;

for(int i=0; i< control.maxSteps; ++i) {
pos = -1.0 + 2.0 * fract(0.5 * pos + 0.5);
k = t / dot(pos,pos);
pos *= k * control.foam;
scale *= k * control.foam;
orbitTrap = min(orbitTrap, float4(abs(pos), dot(pos,pos)));
}

return 1.5 * (0.25 * abs(pos.y) / scale);
}

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Keywords: refract
Posted by: kosalos