72 lines
2.4 KiB
C++
72 lines
2.4 KiB
C++
#ifndef CONSTANT_MEDIUM_H
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#define CONSTANT_MEDIUM_H
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#include "rayTracer.h"
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#include "hittable.h"
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#include "material.h"
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#include "texture.h"
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class constantMedium : public hittable {
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public:
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constantMedium(shared_ptr<hittable> boundary, double density, shared_ptr<texture> tex): boundary(boundary), negInvDensity(-1 / density), phaseFunction(make_shared<isotropic>(tex)) {}
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constantMedium(shared_ptr<hittable> boundary, double density, const colour& albedo) : boundary(boundary), negInvDensity(-1 / density), phaseFunction(make_shared<isotropic>(albedo)) {}
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bool hit(const ray& r, interval ray_t, hitRecord& rec) const override {
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// Print occasional samples when debugging. To enable, set enableDebug true.
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const bool enableDebug = false;
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const bool debugging = enableDebug && randomDouble() < 0.00001;
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hitRecord rec1, rec2;
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if (!boundary->hit(r, interval::universe, rec1))
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return false;
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if (!boundary->hit(r, interval(rec1.t+0.0001, infinity), rec2))
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return false;
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if (debugging) std::clog << "\nt_min=" << rec1.t << ", t_max=" << rec2.t << '\n';
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if (rec1.t < ray_t.min) rec1.t = ray_t.min;
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if (rec2.t > ray_t.max) rec2.t = ray_t.max;
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if (rec1.t >= rec2.t)
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return false;
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if (rec1.t < 0)
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rec1.t = 0;
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auto rayLength = r.direction().length();
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auto distanceInsideBoundary = (rec2.t - rec1.t) * rayLength;
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auto hitDistance = negInvDensity * log(randomDouble());
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if (hitDistance > distanceInsideBoundary)
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return false;
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rec.t = rec1.t + hitDistance / rayLength;
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rec.p = r.at(rec.t);
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if (debugging) {
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std::clog << "hit_distance = " << hitDistance << '\n'
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<< "rec.t = " << rec.t << '\n'
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<< "rec.p = " << rec.p << '\n';
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}
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rec.normal = vec3(1,0,0); // arbitrary
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rec.frontFace = true; // also arbitrary
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rec.mat = phaseFunction;
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return true;
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}
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aabb boundingBox() const override {
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return boundary->boundingBox();
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}
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private:
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shared_ptr<hittable> boundary;
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double negInvDensity;
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shared_ptr<material> phaseFunction;
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};
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#endif |