collision.cpp

/**
* \author Marie DARRIGOL & Anthony LEONARD & Ophélie PELLOUX-PRAYER & Olivier SOLDANO
* \project Ray-Tracing
* \class collision.cpp
* \brief Algorithm naif of collision
*/
#include "collision.h"
#include <limits>

pair<Vec3, SceneObject*> collide(Ray &ray, vector<SceneObject*>& sceneObjects){
	// init the best impact point to the ray position
	Vec3 best_impact_point = ray.getOrigin();
	// get the origin of the ray
	Vec3 ray_origin = ray.getOrigin();
	// declare the best scene object;
	SceneObject* best_sceneObject = nullptr;
	// declare the best distance
	float best_dist = numeric_limits<float>::infinity();
	// declare the current distance
	float dist = 0.0;
	// declare the pair for the intersect function
	pair<bool, Vec3> pair_intersect;
	// declare impact point
	Vec3 impact_point;
	//for each object of the scene
	for (vector<SceneObject*>::iterator it = sceneObjects.begin(); it != sceneObjects.end(); it++){
		// determine if the ray intersect the object
		pair_intersect = (*it)->intersect(ray);
		if (pair_intersect.first){
			// compute the distance between the ray and the impact point
			impact_point = pair_intersect.second - ray_origin;
			dist = impact_point.length();
			// if it's the best
			if (best_dist > dist){
				best_dist = dist;
				best_sceneObject = *it;
				best_impact_point = pair_intersect.second;
			}
		}
	}
	return pair<Vec3, SceneObject*>(best_impact_point, best_sceneObject);
}

pair<Vec3, SceneObject*> collide(Ray &ray, Scene &scene){
	// get the vector of scene object of the scene
	vector<SceneObject*>* sceneObjects = scene.getSceneObjects();
	return collide(ray, *sceneObjects);
}

bool is_collisionned(Ray &ray, vector<SceneObject*>& sceneObjects){
	// declare the pair for the intersect function
	pair<bool, Vec3> pair_intersect;
	//for each object of the scene
	for (vector<SceneObject*>::iterator it = sceneObjects.begin(); it != sceneObjects.end(); it++){
		// determine if the ray intersect the object
		pair_intersect = (*it)->intersect(ray);
		if (pair_intersect.first){
			return true;
		}
	}
	return false;
}