97 lines
3 KiB
C++
97 lines
3 KiB
C++
#include "common/ray.h"
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#include "primitive/box.h"
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#include <cmath>
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#include <utility>
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// Constructor /////////////////////////////////////////////////////////////////
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Box::Box(std::shared_ptr<Shader> const &shader) : Primitive(shader), size(Vector3d(1, 1, 1)) {}
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Box::Box(Vector3d const ¢er, Vector3d const &size, std::shared_ptr<Shader> const &shader)
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: Primitive(shader), center(center), size(size) {}
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// Helper functions /////////////////////////////////////////////////////////
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float intersectionParameterDimension(Vector3d bounds, Ray &ray, int dimension)
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{
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return (bounds[dimension] - ray.origin[dimension]) / ray.direction[dimension];
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}
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Vector3d intersectionParameter(Vector3d bounds, Ray &ray)
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{
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return Vector3d(intersectionParameterDimension(bounds, ray, 0),
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intersectionParameterDimension(bounds, ray, 1),
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intersectionParameterDimension(bounds, ray, 2));
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}
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// Primitive functions /////////////////////////////////////////////////////////
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bool Box::intersect(Ray &ray) const
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{
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// IMPLEMENT ME!
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// Determine whether the ray intersects the box
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Vector3d minBounds(this->minimumBounds(0), this->minimumBounds(1), this->minimumBounds(2));
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Vector3d maxBounds(this->maximumBounds(0), this->maximumBounds(1), this->maximumBounds(2));
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Vector3d tMin = intersectionParameter(minBounds, ray);
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Vector3d tMax = intersectionParameter(maxBounds, ray);
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Vector3d tInAll = Vector3d(std::min(tMin[0], tMax[0]), std::min(tMin[1], tMax[1]), std::min(tMin[2], tMax[2]));
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Vector3d tOutAll = Vector3d(std::max(tMin[0], tMax[0]), std::max(tMin[1], tMax[1]), std::max(tMin[2], tMax[2]));
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float tIn = std::max(std::max(tInAll[0], tInAll[1]), tInAll[2]);
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float tOut = std::min(std::min(tOutAll[0], tOutAll[1]), tOutAll[2]);
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if (tIn > tOut || tOut < 0)
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{
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return false;
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}
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float t = tIn;
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// Test whether this is the foremost primitive in front of the camera
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if (t >= ray.length)
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{
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return false;
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}
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// (Optional for now) Calculate the normal
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// On what side of the box did the ray hit?
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Vector3d normal;
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if (tInAll[0] == tIn)
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{
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normal = Vector3d(1, 0, 0);
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}
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else if (tInAll[1] == tIn)
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{
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normal = Vector3d(0, 1, 0);
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}
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else // tInAll[2] == tIn
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{
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normal = Vector3d(0, 0, 1);
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}
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// Make sure sign is correct
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if (dotProduct(ray.direction, normal) > 0)
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{
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normal = -normal;
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}
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ray.normal = normalized(normal);
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// (Optional for now) Calculate the surface position
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// Set the new length and the current primitive
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ray.length = t;
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ray.primitive = this;
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return false;
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}
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// Bounding box ////////////////////////////////////////////////////////////////
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float Box::minimumBounds(int dimension) const { return this->center[dimension] - this->size[dimension] / 2; }
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float Box::maximumBounds(int dimension) const { return this->center[dimension] + this->size[dimension] / 2; }
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