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/*

 *  harmonics.cpp

 *  GEL

 *

 *  Created by J. Andreas Bærentzen on 01/09/08.

 *  Copyright 2008 __MyCompanyName__. All rights reserved.

 *

 */

#include <iostream>

#include <CGLA/Vec3f.h>

#include <CGLA/Vec3d.h>

#include <LinAlg/Matrix.h>

#include <LinAlg/Vector.h>

#include <LinAlg/LapackFunc.h>

#include <GL/glew.h>

#include <GLGraphics/glsl_shader.h>

#include <HMesh/Manifold.h>

#include <HMesh/VertexCirculator.h>

#include <HMesh/FaceCirculator.h>

#include <HMesh/build_manifold.h>

#include <HMesh/mesh_optimization.h>

#include <HMesh/triangulate.h>

#include <HMesh/load.h>

#include <HMesh/x3d_save.h>

#include <GLConsole/GLConsole.h>

#include "harmonics.h"

#include "wireframe.h"

using namespace CGLA;

using namespace std;

using namespace HMesh;

using namespace Geometry;

using namespace GLGraphics;

using namespace LinAlg;

int E = 1; 	

int MAX_E;

namespace

{

	GLuint prog_P0;

	vector<double> projx;

	vector<double> projy;

	vector<double> projz;

	CMatrix Q;

	CVector V;

	vector<float> max_eig_values;

	vector<Vec3f> vertex_positions;

	double voronoi_area(VertexIter v)

	{

	double area_mixed = 0;

	//For each triangle T from the 1-ring neighborhood of x

	for(VertexCirculator vc(v); !vc.end(); ++vc)

	{

		FaceIter f = vc.get_face();

		double f_area = area(f);

		HalfEdgeIter he = vc.get_halfedge();

		Vec3d v1(he->vert->pos);

		Vec3d v2(he->next->vert->pos);

		Vec3d v0(he->next->next->vert->pos);

		double a0 = acos(dot(v1-v0, v2-v0)/(length(v1-v0)*length(v2-v0)));

		double a1 = acos(dot(v2-v1, v0-v1)/(length(v2-v1)*length(v0-v1)));

		double a2 = acos(dot(v0-v2, v1-v2)/(length(v0-v2)*length(v1-v2)));

		if(a0>(M_PI/2.0) && a1>(M_PI/2.0) && a2>(M_PI/2.0)) // f is non-obtuse

		{

			// Add Voronoi formula (see Section 3.3)

			area_mixed += (1.0/8) * 

			((1.0/tan(a1)) * sqr_length(v2-v0) + 

			 (1.0/tan(a2)) * sqr_length(v1-v0));

		}

		else // Voronoi inappropriate

		{

			// Add either area(f)/4 or area(f)/2

			if(a0>M_PI/2.0)// the angle of f at x is obtuse

				area_mixed += f_area/2;

			else

				area_mixed += f_area/4;

		}

	}

	return area_mixed;

}

	double barycentric_area(VertexIter v)

	{

	double barea = 0;

	//For each triangle T from the 1-ring neighborhood of x

	for(VertexCirculator vc(v); !vc.end(); ++vc)

	{

		FaceIter f = vc.get_face();

		barea += area(f)/3.0;

	}

	return barea;

}

}

void make_laplace_operator(Manifold& mani)

{

	Q.Resize(mani.no_vertices(), mani.no_vertices());

	for(VertexIter v = mani.vertices_begin(); v != mani.vertices_end(); ++v)

		if(!is_boundary(v))

		{

			int i = v->touched;

			double area_i = voronoi_area(v);

			Vec3d vertex(v->pos);

			Vec3d curv_normal(0);

			double a_sum = 0;

			for(VertexCirculator vc(v); !vc.end(); ++vc)

			{

				int j = vc.get_vertex()->touched;

				double area_j = voronoi_area(vc.get_vertex());

				HalfEdgeIter h = vc.get_halfedge();

				Vec3d nbr(h->vert->pos);

				Vec3d left(h->next->vert->pos);

				Vec3d right(h->opp->prev->opp->vert->pos);

				double d_left = dot(normalize(nbr-left),

									normalize(vertex-left));

				double d_right = dot(normalize(nbr-right),

									 normalize(vertex-right));

				double a_left  = acos(min(1.0, max(-1.0, d_left)));

				double a_right = acos(min(1.0, max(-1.0, d_right)));

				double w = 1.0/tan(a_left) + 1.0/tan(a_right);

				Q[i][j] = -w/sqrt(area_i*area_j);						

				//Q[i][j] = -1;						

				a_sum += Q[i][j];

			}

			Q[i][i] = -a_sum;

		}

	EigenSolutionsSym(Q,V);

}

void analyze_mesh(Manifold& mani)

{

	static bool was_here = false;

	if(!was_here)

	{

		triangulate(mani);

		mani.enumerate_vertices();

		MAX_E = mani.no_vertices()-1;

		E = min(E, MAX_E);

		was_here = true;

		make_laplace_operator(mani);

		vertex_positions.resize(mani.no_vertices());

	}

	projx.resize(MAX_E);

	projy.resize(MAX_E);

	projz.resize(MAX_E);

	max_eig_values.resize(MAX_E, 1e-10);

	for(int es=0; es<MAX_E; ++es)

	{

		for(VertexIter v=mani.vertices_begin(); v != mani.vertices_end(); ++v)

		{

			projx[es] += v->pos[0] * Q[es][v->touched];

			projy[es] += v->pos[1] * Q[es][v->touched];

			projz[es] += v->pos[2] * Q[es][v->touched];

			max_eig_values[es] = max(max_eig_values[es], static_cast<float>(abs(Q[es][v->touched])));

		}

	}

}

void add_frequency(Manifold& mani, int es, float scale)

{

	if(es<MAX_E)

		for(VertexIter v=mani.vertices_begin(); v != mani.vertices_end(); ++v)

		{

			Vec3f& p = vertex_positions[v->touched]; 

			p[0] += projx[es]* Q[es][v->touched] * scale;

			p[1] += projy[es]* Q[es][v->touched] * scale;

			p[2] += projz[es]* Q[es][v->touched] * scale;

		}

}

void reset_shape(Manifold& mani)

{

	for(VertexIter v=mani.vertices_begin(); v != mani.vertices_end(); ++v)

		vertex_positions[v->touched] = Vec3f(0);	

}

void reconstruct(Manifold& mani, int E)

{

	reset_shape(mani);

	for(int es=0;es<=E;++es)

		add_frequency(mani,es);

}

void partial_reconstruct(Manifold& mani, int E0, int E1, float scale)

{

	for(int es=E0;es<=E1;++es)

		add_frequency(mani,es, scale);

}

void draw_eigenvalues(Manifold& m)

{

	static CVar<int> display_eigen("display.eigenvalue",0);

	static CVar<int> display_eigen2("display.eigenvalue2",0);

	static CVar<int> do_highlight("display.highlight",1);

	static CVar<int> do_diffuse("display.diffuse",1);

	glUseProgram(prog_P0);

	glUniform1f(glGetUniformLocation(prog_P0,"eig_max"),max_eig_values[display_eigen]);

	glUniform1f(glGetUniformLocation(prog_P0,"eig_max2"),max_eig_values[display_eigen2]);

	glUniform1i(glGetUniformLocation(prog_P0,"do_diffuse"),do_diffuse);

   	glUniform1i(glGetUniformLocation(prog_P0,"do_highlight"),do_highlight);

	GLuint attrib = glGetAttribLocationARB(prog_P0, "eigenvalue");

	GLuint attrib2 = glGetAttribLocationARB(prog_P0, "eigenvalue2");

	glFrontFace(GL_CW);

	for(FaceIter f=m.faces_begin(); f != m.faces_end(); ++f)

	{

		FaceCirculator fc(f);

		glBegin(GL_TRIANGLES);

		while(!fc.end())

		{

			int i = fc.get_vertex()->touched;

			glVertexAttrib1f(attrib,Q[display_eigen][i]);

			glVertexAttrib1f(attrib2,Q[display_eigen2][i]);

			glNormal3fv(normal(fc.get_vertex()).get());

			glVertex3fv(vertex_positions[i].get());

			++fc;

		}

		glEnd();

	}

	glFrontFace(GL_CCW);

	glUseProgram(0);

}

void init_harmonics(Manifold& mani)

{

	string shader_path = "/Users/jab/GEL/apps/MeshEdit/";

	GLuint vs = create_glsl_shader(GL_VERTEX_SHADER, shader_path, "tri.vert");

	GLuint fs = create_glsl_shader(GL_FRAGMENT_SHADER, shader_path, "tri.frag");

	// Create the program

	prog_P0 = glCreateProgram();

	// Attach all shaders

	if(vs) glAttachShader(prog_P0, vs);

	if(fs) glAttachShader(prog_P0, fs);

	// Link the program object and print out the info log

	glLinkProgram(prog_P0);

	print_glsl_program_log(prog_P0);

	// Install program object as part of current state

	glUseProgram(prog_P0);

	analyze_mesh(mani);

	reconstruct(mani, MAX_E);

}