112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
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#include "marbleshader.h"
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Color MarbleShader::shade(const Scene &scene, const Ray &ray) const
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{ // Get the intersection point of the ray and the object
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Vector3d intersection = ray.origin + ray.direction * ray.length;
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// Create a noise value based on the intersection point
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float noise = getMarbleNoise(intersection, scale);
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// return noise * Color(1, 1, 1);
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// Use the noise value to determine the color of the marble
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Color color = baseColor;
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if (noise > 0.5)
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{
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float fade = 1 - (noise - 0.5f) * 2 * edgeFade;
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fade = clamp(fade, 0, 1);
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color = color + (veinColor - baseColor) * fade;
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}
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// Get the lighting for the point
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// for (const auto &light: scene.lights())
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// {
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// Light::Illumination illum = light->illuminate(scene, ray);
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// color = color * illum.color;
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// }
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return color;
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}
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MarbleShader::MarbleShader(Color baseColor, Color veinColor, float scale, float edgeFade)
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: baseColor(baseColor), veinColor(veinColor), scale(scale), edgeFade(edgeFade)
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{
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}
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float MarbleShader::getMarbleNoise(Vector3d position, float scale) const
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{
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float x = position.x * scale;
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float y = position.y * scale;
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float z = position.z * scale;
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// Calculate the integer coordinates of the point
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int xi = (int)floor(x);
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int yi = (int)floor(y);
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int zi = (int)floor(z);
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int xo = xi + 1;
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int yo = yi + 1;
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int zo = zi + 1;
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// Calculate colors of the corners in a three-dimensional vector
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float cube[2][2][2];
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srand(xi + yi * 57 + zi * 997);
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cube[0][0][0] = rand() / (float)RAND_MAX;
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srand(xo + yi * 57 + zi * 997);
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cube[1][0][0] = rand() / (float)RAND_MAX;
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srand(xi + yo * 57 + zi * 997);
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cube[0][1][0] = rand() / (float)RAND_MAX;
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srand(xo + yo * 57 + zi * 997);
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cube[1][1][0] = rand() / (float)RAND_MAX;
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srand(xi + yi * 57 + zo * 997);
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cube[0][0][1] = rand() / (float)RAND_MAX;
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srand(xo + yi * 57 + zo * 997);
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cube[1][0][1] = rand() / (float)RAND_MAX;
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srand(xi + yo * 57 + zo * 997);
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cube[0][1][1] = rand() / (float)RAND_MAX;
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srand(xo + yo * 57 + zo * 997);
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cube[1][1][1] = rand() / (float)RAND_MAX;
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// Calculate the fractional part of the point
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float xf = x - xi;
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float yf = y - yi;
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float zf = z - zi;
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// Interpolate along x
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float dot1 = smoothstep(cube[0][0][0], cube[1][0][0], xf);
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float dot2 = smoothstep(cube[0][1][0], cube[1][1][0], xf);
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float dot3 = smoothstep(cube[0][0][1], cube[1][0][1], xf);
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float dot4 = smoothstep(cube[0][1][1], cube[1][1][1], xf);
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// Interpolate along y
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float dot5 = smoothstep(dot1, dot2, yf);
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float dot6 = smoothstep(dot3, dot4, yf);
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// Interpolate along z
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float dot7 = smoothstep(dot5, dot6, zf);
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return dot7;
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}
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float MarbleShader::smoothstep(float edge0, float edge1, float x) const {
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float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
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return t * t * (3 - 2 * t);
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}
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float MarbleShader::lerp(float a, float b, float t) const {
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return a + t * (b - a);
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}
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float MarbleShader::clamp(float x, float lower, float upper) const {
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return std::max(lower, std::min(x, upper));
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}
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