#include <GL/gl.h>
#include <GL/glut.h>
#include <stdio.h>
#include <math.h>

GLfloat texture[10];

const int ParticleCount = 500;

typedef struct
{
double Xpos;
double Ypos;
double Zpos;
double Xmov;
double Zmov;
double Red;
double Green;
double Blue;
double Direction;
double Acceleration;
double Deceleration;
double Scalez;
bool Visible;
}PARTICLES;

PARTICLES Particle[ParticleCount];

GLuint LoadTextureRAW( const char * filename, int width, 
int height);
void FreeTexture( GLuint texturez );

void square (void) {
    glBindTexture( GL_TEXTURE_2D, texture[0] );
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0);
    glVertex2d(-1.0,-1.0);
    glTexCoord2d(1.0,0.0);
    glVertex2d(1.0,-1.0);
    glTexCoord2d(1.0,1.0);
    glVertex2d(1.0,1.0);
    glTexCoord2d(0.0,1.0);
    glVertex2d(-1.0,1.0);
    glEnd();
}

void glCreateParticles (void) {
int i;
for (i = 1; i < ParticleCount; i++){
    Particle[i].Xpos = 0;
    Particle[i].Ypos = -5;
    Particle[i].Zpos = -5;
    Particle[i].Xmov = (((((((2 - 1 + 1) * rand()%11) + 1) - 1 + 1) *
    rand()%11) + 1) * 0.005) - (((((((2 - 1 + 1) * rand()%11) + 1) - 1 + 1
    ) * rand()%11) + 1) * 0.005);
    Particle[i].Zmov = (((((((2 - 1 + 1) * rand()%11) + 1) - 1 + 1) *
    rand()%11) + 1) * 0.005) - (((((((2 - 1 + 1) * rand()%11) + 1) - 1 + 1
    ) * rand()%11) + 1) * 0.005);
    Particle[i].Red = 1;
    Particle[i].Green = 1;
    Particle[i].Blue = 1;
    Particle[i].Scalez = 0.25;
    Particle[i].Direction = 0;
    Particle[i].Acceleration = ((((((8 - 5 + 2) * rand()%11) + 5
    ) - 1 + 1) * rand()%11) + 1) * 0.02;
    Particle[i].Deceleration = 0.0025;
}
}
void glUpdateParticles (void) {
int i;
for (i = 1; i < ParticleCount; i++)
{

glColor3f ((float)(rand()%100)/100.0,(float)(rand()%100)/100.0,(float)(rand()%100)/100.0);

Particle[i].Ypos = Particle[i].Ypos + Particle[i]
.Acceleration - Particle[i].Deceleration;
Particle[i].Deceleration = Particle[i].Deceleration +
0.0025;

Particle[i].Xpos = Particle[i].Xpos + Particle[i].Xmov;
Particle[i].Zpos = Particle[i].Zpos + Particle[i].Zmov;

Particle[i].Direction = Particle[i].Direction + ((((((int
)(0.5 - 0.1 + 0.1) * rand()%11) + 1) - 1 + 1) * rand()%11) + 1);

if (Particle[i].Ypos < -5)
{
Particle[i].Xpos = 0;
Particle[i].Ypos = -5;
Particle[i].Zpos = -5;
Particle[i].Red = 1;
Particle[i].Green = 1;
Particle[i].Blue = 1;
Particle[i].Direction = 0;
Particle[i].Acceleration = ((((((8 - 5 + 2) * rand()%11) + 5
) - 1 + 1) * rand()%11) + 1) * 0.02;
Particle[i].Deceleration = 0.0025;
}

}
}

void glDrawParticles (void) {
int i;
for (i = 1; i < ParticleCount; i++)
{
glPushMatrix();

    glTranslatef (Particle[i].Xpos, Particle[i].Ypos, Particle[i].Zpos);
    glRotatef (Particle[i].Direction - 90, 0, 0, 1);
   
    glScalef (Particle[i].Scalez, Particle[i].Scalez, Particle[i].Scalez);
   
    glDisable (GL_DEPTH_TEST);
    glEnable (GL_BLEND);
        
    glBlendFunc (GL_DST_COLOR, GL_ZERO);
    glBindTexture (GL_TEXTURE_2D, texture[0]);
    
    glBegin (GL_QUADS);
    glTexCoord2d (0, 0);
    glVertex3f (-1, -1, 0);
    glTexCoord2d (1, 0);
    glVertex3f (1, -1, 0);
    glTexCoord2d (1, 1);
    glVertex3f (1, 1, 0);
    glTexCoord2d (0, 1);
    glVertex3f (-1, 1, 0);
    glEnd();
    
    glBlendFunc (GL_ONE, GL_ONE);
    glBindTexture (GL_TEXTURE_2D, texture[1]);
    
    glBegin (GL_QUADS);
    glTexCoord2d (0, 0);
    glVertex3f (-1, -1, 0);
    glTexCoord2d (1, 0);
    glVertex3f (1, -1, 0);
    glTexCoord2d (1, 1);
    glVertex3f (1, 1, 0);
    glTexCoord2d (0, 1);
    glVertex3f (-1, 1, 0);
    glEnd();

    glEnable(GL_DEPTH_TEST);

glPopMatrix();

}
}

void display (void) {
    glClearDepth (1);
    glClearColor (0.0,0.0,0.0,1.0);
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();  
    glTranslatef (0,0,-10);
    glUpdateParticles();
    glDrawParticles();
    glutSwapBuffers();
}

void init (void) {
    glEnable( GL_TEXTURE_2D );
    glEnable(GL_DEPTH_TEST);

    glCreateParticles();

    texture[0] = LoadTextureRAW( "particle_mask.raw",256,256
); //load our texture
    texture[1] = LoadTextureRAW( "particle.raw",256,256);
//load our texture
}

void reshape (int w, int h) {
    glViewport (0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();
    gluPerspective (60, (GLfloat)w / (GLfloat)h, 1.0, 100.0);
    glMatrixMode (GL_MODELVIEW);
}

int main (int argc, char **argv) {
    glutInit (&argc, argv);
    glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
    glutInitWindowSize (500, 500);
    glutInitWindowPosition (100, 100);
    glutCreateWindow ("A basic OpenGL Window");
    init();
    glutDisplayFunc (display);
    glutIdleFunc (display);
    glutReshapeFunc (reshape);
    glutMainLoop ();
    return 0;
}

//function to load the RAW file

GLuint LoadTextureRAW( const char * filename, int width, 
int height )
{
  GLuint texture;
  unsigned char * data;
  FILE * file;

  file = fopen( filename, "rb" );
  if ( file == NULL ) return 0;

  data = (unsigned char *)malloc( width * height * 3 );

  fread( data, width * height * 3, 1, file );
  fclose( file );

  glGenTextures(1, &texture );            

  glBindTexture(GL_TEXTURE_2D, texture);

  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, 
GL_REPEAT);
  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, 
GL_REPEAT);

  glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, 
GL_MODULATE );

  glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
 GL_LINEAR_MIPMAP_NEAREST );

  glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
 GL_LINEAR );

  gluBuild2DMipmaps(GL_TEXTURE_2D, 3, width, height, 
GL_RGB, GL_UNSIGNED_BYTE, data);

  free( data );

  return texture;
}

void FreeTexture( GLuint texture )
{
  glDeleteTextures( 1, &texture );
}