#include "marbleshader.h"

Color MarbleShader::shade(const Scene &scene, const Ray &ray) const
{    // Get the intersection point of the ray and the object
    Vector3d intersection = ray.origin + ray.direction * ray.length;

    // Create a noise value based on the intersection point
    float noise = getMarbleNoise(intersection, scale);

//    return noise * Color(1, 1, 1);

    // Use the noise value to determine the color of the marble
    Color color = baseColor;
    if (noise > 0.5)
    {
        float fade = 1 - (noise - 0.5f) * 2 * edgeFade;
        fade = clamp(fade, 0, 1);
        color = color + (veinColor - baseColor) * fade;
    }

    // Get the lighting for the point
//    for (const auto &light: scene.lights())
//    {
//        Light::Illumination illum = light->illuminate(scene, ray);
//        color = color * illum.color;
//    }

    return color;
}

MarbleShader::MarbleShader(Color baseColor, Color veinColor, float scale, float edgeFade)
        : baseColor(baseColor), veinColor(veinColor), scale(scale), edgeFade(edgeFade)
{

}

float MarbleShader::getMarbleNoise(Vector3d position, float scale) const
{
    float x = position.x * scale;
    float y = position.y * scale;
    float z = position.z * scale;

    // Calculate the integer coordinates of the point
    int xi = (int)floor(x);
    int yi = (int)floor(y);
    int zi = (int)floor(z);

    int xo = xi + 1;
    int yo = yi + 1;
    int zo = zi + 1;

    // Calculate colors of the corners in a three-dimensional vector
    float cube[2][2][2];

    srand(xi + yi * 57 + zi * 997);
    cube[0][0][0] = rand() / (float)RAND_MAX;

    srand(xo + yi * 57 + zi * 997);
    cube[1][0][0] = rand() / (float)RAND_MAX;

    srand(xi + yo * 57 + zi * 997);
    cube[0][1][0] = rand() / (float)RAND_MAX;

    srand(xo + yo * 57 + zi * 997);
    cube[1][1][0] = rand() / (float)RAND_MAX;

    srand(xi + yi * 57 + zo * 997);
    cube[0][0][1] = rand() / (float)RAND_MAX;

    srand(xo + yi * 57 + zo * 997);
    cube[1][0][1] = rand() / (float)RAND_MAX;

    srand(xi + yo * 57 + zo * 997);
    cube[0][1][1] = rand() / (float)RAND_MAX;

    srand(xo + yo * 57 + zo * 997);
    cube[1][1][1] = rand() / (float)RAND_MAX;

    // Calculate the fractional part of the point
    float xf = x - xi;
    float yf = y - yi;
    float zf = z - zi;

    // Interpolate along x
    float dot1 = smoothstep(cube[0][0][0], cube[1][0][0], xf);
    float dot2 = smoothstep(cube[0][1][0], cube[1][1][0], xf);
    float dot3 = smoothstep(cube[0][0][1], cube[1][0][1], xf);
    float dot4 = smoothstep(cube[0][1][1], cube[1][1][1], xf);

    // Interpolate along y
    float dot5 = smoothstep(dot1, dot2, yf);
    float dot6 = smoothstep(dot3, dot4, yf);

    // Interpolate along z
    float dot7 = smoothstep(dot5, dot6, zf);

    return dot7;
}

float MarbleShader::smoothstep(float edge0, float edge1, float x) const {
    float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
    return t * t * (3 - 2 * t);
}

float MarbleShader::lerp(float a, float b, float t) const {
    return a + t * (b - a);
}

float MarbleShader::clamp(float x, float lower, float upper) const {
    return std::max(lower, std::min(x, upper));
}