Attempt at marble shader

shader/marbleshader.cpp

@@ -0,0 +1,111 @@
+#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));
+}

shader/marbleshader.h

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+#ifndef CG1_TRACER_MARBLESHADER_H
+#define CG1_TRACER_MARBLESHADER_H
+
+
+#include "shader.h"
+#include "light/light.h"
+#include "scene/scene.h"
+
+class MarbleShader : public Shader
+{
+public:
+    // Constructor
+    explicit MarbleShader(Color baseColor = Color(1, 1, 1), Color veinColor = Color(0, 0, 0), float scale = 1.0f, float edgeFade = 1.0f);
+
+    // Shader functions
+    virtual Color shade(Scene const &scene, Ray const &ray) const;
+
+    Color baseColor;
+    Color veinColor;
+    Color shadowColor;
+    float scale;
+    float edgeFade;
+
+    float getMarbleNoise(Vector3d position, float scale) const;
+
+    float lerp(float a, float b, float t) const;
+
+    float smoothstep(float edge0, float edge1, float x) const;
+
+    float clamp(float x, float lower, float upper) const;
+};
+
+
+#endif //CG1_TRACER_MARBLESHADER_H