#include <cstdio>
#include <cmath>
#include "tri_mesh.h"
#include "ray_intersect.h"
static double infinity = -log(0);

void tri_mesh::load(const char*file)
{
	FILE*F = fopen(file, "r");
	if(!F) return;

	char buff[1000];

	while(!feof(F))
	{
		fgets(buff, sizeof buff, F);
		if(*buff == 'v')
		{
			double x, y, z;
			if(sscanf(buff, "v %lg %lg %lg", &x, &y, &z) == 3)
			{
			pts.push_back(vector3d(x, y, z));
			}
		}
		else if(*buff == 'f')
		{
			int x, y, z;
			if(sscanf(buff, "f %d %d %d", &x, &y, &z) == 3)
			{
				tris.push_back(tri_struct(x-1, y-1, z-1));
			}
		}
	}

	fclose(F);
	CalcNorms();
}

void tri_mesh::CalcNorms()
{
	for(size_t i=0; i<tris.size(); i++)
	{
		tri_struct& ts = tris[i];
		ts.norm = (pts[ts.b]-pts[ts.a]).cross(pts[ts.c]-pts[ts.a]);
		ts.norm.make_unit();
	}
	if(phong)
	{
		norms.clear();
		for(size_t i=0; i<pts.size(); i++)
			norms.push_back(vec_zero);

		for(size_t i=0; i<tris.size(); i++)
		{
			tri_struct & ts = tris[i];
			norms[ts.a]+=ts.norm;
			norms[ts.b]+=ts.norm;
			norms[ts.b]+=ts.norm;
		}

		for(size_t i=0; i<pts.size(); i++)
			norms[i].make_unit();
	}
}

RayIntersect tri_mesh::CalcRayIntersect(Ray ray)
{
	int min_index = -1;
	double min_t = infinity;
	double aa, bb, baa, bbb;
	for(size_t i=0; i<tris.size(); i++)
	{
		tri_struct & ts = tris[i];

		// Culling
		if(ts.norm * ray.d > 0)
			continue;
		double t = intersect_triangle_ray(ray, pts[ts.a],
										  pts[ts.b], pts[ts.c],
										  aa, bb);
		if(t > 0 && t < min_t)
		{
			min_t = t;
			min_index = i;
			baa = aa;
			bbb = bb;
		}
	}
	RayIntersect ri;
	ri.special0 = baa;
	ri.special1 = bbb;
	if(min_t < infinity)
	{
		ri.param_t = min_t;
		ri.E = this;
		ri.special = min_index;
	}
	else
	{
		ri.param_t = -1;
		ri.E = 0;
		ri.special = -1;
	}
	return ri;
}

void tri_mesh::PathCompress(const Transform&T,
							queue<pair<Entity*, Transform> >&Q,
							vector<Entity*>&V)
{
	tri_mesh * tm = new tri_mesh;
	tm->tris = tris;
	tm->phong = phong;
	tm->kd = kd;
	tm->ks = ks;
	tm->ka = ka;
	tm->n = n;
	for(size_t i=0; i<pts.size(); i++)
		tm->pts.push_back(T * pts[i]);
	tm->CalcNorms();
	V.push_back(tm);
}

int tri_mesh::IntersectionTest(Ray ray)
{
	for(size_t i=0; i<tris.size(); i++)
	{
		double aa, bb;
		tri_struct & ts = tris[i];

		if(ts.norm * ray.d > 0)
			continue;

		double t = intersect_triangle_ray(ray, pts[ts.a],
										  pts[ts.b], pts[ts.c],
										  aa, bb);
		if(t > 1e-1) return 1;
	}
	return 0;
}