//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop

#include "BackgroundStars.h"
#include <math.h>


TBackgroundStarField::TBackgroundStarField()
{
    int i;
    float distance;

// randomly initalise the stars
    randomize();
    for(i=0; i<NUM_STARS; i++)
    {
        m_Stars[i].size=((float)random(10)/10.0f);
        do
        {
            m_Stars[i].x=(float)((STAR_FIELD_SIZE/2)-random(STAR_FIELD_SIZE));
            m_Stars[i].y=(float)((STAR_FIELD_SIZE/2)-random(STAR_FIELD_SIZE));
            m_Stars[i].z=(float)((STAR_FIELD_SIZE/2)-random(STAR_FIELD_SIZE));
            distance=sqrt(m_Stars[i].x*m_Stars[i].x+m_Stars[i].y*m_Stars[i].y+
                m_Stars[i].z*m_Stars[i].z);
        }
        // this checks to make sure the middle of the star field is empty so
        // no stars intersect with planets
        while(distance<(1*STAR_FIELD_SIZE)/3.0f);
    }
}

TBackgroundStarField::~TBackgroundStarField()
{
}

void TBackgroundStarField::Draw( void )
{
    int i;

// don't want the stars lit
    glDisable(GL_LIGHTING);
// set the point drawing size to slightly larger than normal
    glPointSize(2.0f);
// draw the stars
    for(i=0; i<NUM_STARS; i++)
    {
    // set an appropriate brightness based on the stars size
        glColor4f(m_Stars[i].size, m_Stars[i].size, m_Stars[i].size, 1.0f);
    // draw the star
        glBegin(GL_POINTS);
            glVertex3f(m_Stars[i].x, m_Stars[i].y, m_Stars[i].z);
        glEnd();
    }
// set the point size back to normal
    glPointSize(1.0f);
// reenable the lighting
    glEnable(GL_LIGHTING);
}
//---------------------------------------------------------------------------
#pragma package(smart_init)