#include <GL/glut.h>
#include <iostream>
#include <stdlib.h>
#include <math.h>
#include "circ.h"
#include "Renderer.h"
#include "VecField.h"

using namespace std;

#define NPARTS 1000
#define P_LEN 50

#define FSCALE 2

Renderer::Renderer(int wid, int ht)
{
	int i;

	cursX = cursY = 0.0;	
	circle = new Circ(1.0,36);

	VF = new vecField(wid/FSCALE,ht/FSCALE,FSCALE);
	initParticles();

	Width = wid/FSCALE;
	Height = ht/FSCALE;

	cerr << "W H " << Width << " " << Height << "\n";

	PathsX = new float*[NPARTS];
	PathsY = new float*[NPARTS];

	for(i=0;i<NPARTS;++i)
	{
		PathsX[i] = new float[P_LEN];
		PathsY[i] = new float[P_LEN];
	}

	for(i=0;i<NPARTS;++i)
	{
		traceParticle(PathsX[i], PathsY[i]);
	}
	//cerr << "done Init \n";

}

void Renderer :: updateParms(float &cx,float &cy, float &dx, float &dy )
{
	int i;

	do
		VF->updateParms();
	while(	!AdvectionCrossing(cx, cy));

	for(i=0;i<NPARTS;++i)
	{
		traceParticle(PathsX[i], PathsY[i]);
	}

	VF->getVec(300.0/2.0,300.0/2.0,dx,dy);

	//cerr << "Center Dx Dy " << dx << " " << dy << "\n";	
	
}




void Renderer::updateCursor(float rx,float ry, float &dx, float &dy)// for debugging
{

	cursX = rx;
	cursY = ry;

	VF->getVec(rx/2.0,ry/2.0,dx,dy);
}

// YOUR CODE MAINLY GOES HERE
void Renderer::Draw( int cond)  // orthogonal mesh
{
	int i,j;

	float *XV, *YV;
	float alpha;

	// cond it used to set up the rendering style

	if (cond < 2) glLineWidth(2.0);
	else glLineWidth(1.0);

	if(cond%2 == 0) alpha = 1.0;
	else alpha = 0.5;

	glPushMatrix();

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);

	glScalef(2.0,2.0,0.0);

	glColor4f(0.0,0.8,0.0,alpha);
	for(j=0;j<NPARTS;++j)
	{
		XV = PathsX[j]; YV = PathsY[j];
	    glBegin(GL_LINE_STRIP);
		for(i = 0;i<P_LEN;i = i+5)
		 	glVertex3f(XV[i],YV[i], 0.0);
		 glEnd();	
		 circle->Filled(0.6,XV[i-5],YV[i-5]);
		
	}	
	glPopMatrix();	
}


bool Renderer::AdvectionCrossing(float &cx, float &cy)  // used to determine where the advection path crosses the outer circle
{
	float rad,xx,yy,dx,dy,rx,ry;
	int count = 0;

	xx = yy = 150.0; // start in the center
	rad = 0.0;
	while (rad < 50.0 && count < 300)
	{
		VF->getVec(xx,yy,dx,dy);
		xx +=dx; yy +=dy;
		rx = xx - 150.0; ry = yy - 150.0;
		rad = sqrt(rx*rx + ry*ry);
		++count;
	}

	//cerr << "CROSSING " << " " << xx*2.0 << " " << yy*2.0 << "\n";
	cx = (xx*2.0 - 300.0)/300.0;
	cy = (yy*2.0 - 300.0)/300.0;
	if (count == 300) return false;
	else return true;
}

void Renderer :: traceParticle(float *X, float *Y)
{
	// Traces a particle
	int j;
	float xx,yy;
	float dx,dy;

	xx = Width*float(rand()%1000)/1000.0; // a random start
	yy = Height*float(rand()%1000)/1000.0;

	for (j=0;j< P_LEN;++j)
	{
		X[j] = xx;
		Y[j] = yy;
		
		dx = VF->dX[int(yy)][int(xx)];
		dy = VF->dY[int(yy)][int(xx)];

		xx += 0.5*dx;	  // how far does the particle move
		yy += 0.5*dy;
			
		if (xx > (Width-1.0)) xx = Width-1.0;  // stop
		if (xx < 1.0) xx = 1.0;
		if (yy > (Height-1.0)) yy = Height-1.0;  
		if (yy < 1.0) yy = 0.0;
						
	}	

}



void Renderer::DrawOver()

{
	int i;
	float y;

	glColor3f(0.6,0.6,0.6);
	glRectf(700.0,0.0,605.0,600.0);  
	for(i=0;i<14;++i)
	{
		y = (i+1)*40.0 - 1.0;
		glRectf(700.0,y-2.0,840.0,y+2.0); 
	}
	
	glColor3f(0.3,0.3,0.8);

	circle->Outline(10.0,300.0,300.0);
	circle->Outline(100.0,300.0,300.0);

/*FOR Show and tell
	float rad,xx,yy,dx,dy,rx,ry;
	int count = 0;
	glColor3f(1.0,1.0,0.0);
	glBegin(GL_LINE_STRIP);
	xx = yy = 150.0; // start in the center
	rad = 0.0;
	while (rad < 50.0 && count < 300)
	{
		VF->getVec(xx,yy,dx,dy);
		xx +=dx; yy +=dy;
		rx = xx - 150.0; ry = yy - 150.0;
		rad = sqrt(rx*rx + ry*ry);
		glVertex3f(xx*2,yy*2,0.0);
		++count;
	}
	glEnd();
*/
}

void Renderer::initParticles()
{
	// Sets up a set of random start positions
	int i;
	for (i=0;i<NP;++i)
	{
		x[i] = Width*float(rand()%1000)/1000.0;
		y[i] = Height*float(rand()%1000)/1000.0;
	}
}