Notes

#define PI 3.14159265359

// Rotation matrix for the cube
mat3 rotationMatrix(vec3 axis, float angle) {
axis = normalize(axis);
float s = sin(angle);
float c = cos(angle);
float oc = 1.0 - c;
return mat3(
oc * axis.x * axis.x + c, oc * axis.x * axis.y - axis.z * s, oc * axis.z * axis.x + axis.y * s,
oc * axis.x * axis.y + axis.z * s, oc * axis.y * axis.y + c, oc * axis.y * axis.z - axis.x * s,
oc * axis.z * axis.x - axis.y * s, oc * axis.y * axis.z + axis.x * s, oc * axis.z * axis.z + c
);
}

// Smooth min function for soft edges
float smin(float a, float b, float k) {
float h = clamp(0.5 + 0.5 * (b - a) / k, 0.0, 1.0);
return mix(b, a, h) - k * h * (1.0 - h);
}

// SDF for the cube
float sdCube(vec3 p, float s) {
vec3 d = abs(p) - vec3(s);
return min(max(d.x, max(d.y, d.z)), 0.0) + length(max(d, 0.0));
}

// Color palette function
vec3 palette(float t) {
vec3 a = vec3(0.5, 0.5, 0.5);
vec3 b = vec3(0.5, 0.5, 0.5);
vec3 c = vec3(1.0, 1.0, 1.0);
vec3 d = vec3(0.263, 0.416, 0.557);
return a + b * cos(6.28318 * (c * t + d));
}

// Main distance function
float map(vec3 p, float time) {
// Apply rotation
p *= rotationMatrix(normalize(vec3(1.0, 1.0, 1.0)), time * 0.2);

// Apply breathing effect
float breathe = sin(time * 0.5) * 0.05 + 1.0;
p /= breathe;

// Apply subtle distortion
p += 0.05 * sin(p * 5.0 + time);

return sdCube(p, 1.0);
}

// Normal calculation
vec3 calcNormal(vec3 p, float time) {
const float h = 0.0001;
const vec2 k = vec2(1, -1);
return normalize(
k.xyy * map(p + k.xyy * h, time) +
k.yyx * map(p + k.yyx * h, time) +
k.yxy * map(p + k.yxy * h, time) +
k.xxx * map(p + k.xxx * h, time)
);
}

// Ray marching function
float rayMarch(vec3 ro, vec3 rd, float time) {
float t = 0.0;
for (int i = 0; i < 100; i++) {
vec3 p = ro + rd * t;
float d = map(p, time);
if (d < 0.001 || t > 20.0) break;
t += d * 0.5;
}
return t;
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
vec2 uv = (fragCoord - 0.5 * iResolution.xy) / iResolution.y;
vec2 mouse = iMouse.xy / iResolution.xy;

// Camera setup
vec3 ro = vec3(0.0, 0.0, 5.0);
vec3 rd = normalize(vec3(uv, -1.5));

// Apply user interaction
float interactionStrength = smoothstep(0.0, 0.1, length(mouse));
float timeOffset = interactionStrength * 10.0 * (mouse.x - 0.5);
float time = iTime + timeOffset;

// Ray marching
float t = rayMarch(ro, rd, time);

// Shading
if (t < 20.0) {
vec3 p = ro + rd * t;
vec3 normal = calcNormal(p, time);

// Interior color
vec3 interiorColor = palette(length(p) * 0.1 + time * 0.1);

// Fresnel effect for transparency
float fresnel = pow(1.0 - abs(dot(normal, rd)), 2.0);

// Final color
vec3 color = mix(interiorColor, vec3(1.0), fresnel);

// Add glow
color += vec3(0.1, 0.2, 0.3) * (1.0 - fresnel) * 0.5;

fragColor = vec4(color, 1.0);
} else {
fragColor = vec4(0.0, 0.0, 0.0, 1.0);
}
}