PathTracer1_7

float distanceFromSurface = 0.0;
float step = 0.03;
vec3 previousPosition = vPosition;
float previousDistance = 0.;

for (int i = 0; i < 100; i++) {
    vec3 currentPosition = vPosition + distanceFromSurface * rayDir;
    float distance = sphereDistance(currentPosition, sphereCenter, 1.0);
    if (distance < 0.) {
        vec3 hitPosition = mix(previousPosition, currentPosition, previousDistance / (previousDistance - distance));
        vec3 normal = (hitPosition - sphereCenter);
        float dotLight = dot(normal, ligthDirection) * 0.5 + 0.5;
        float noiseTexture = simplex3d(hitPosition * 4.0) * 0.5 + 0.5;
        gl_FragColor = vec4(vec3(1.0, 0.5, 0.2) * dotLight * noiseTexture, 1.0);
        return;
    }
    distanceFromSurface += step;
    previousPosition = currentPosition;
    previousDistance = distance;
}