Opengl

#include <stdafx.h>
#include<stdlib.h>
#include <time.h>
#include <GL\glut.h>
#include<GL\GLU.h>

#define MAX_PARTICLES 100
#define MAX_BOUNCE_COUNT 10
#define MAX_PARTICLE_AGE 10


struct PARTICLE {
    float X,Y,Z; // Current position
    float sX,sY,sZ; // Current Speed/Movement
    float tX,tY,tZ; // Target Speed/Movement
    float R,B,G; // Particle Colour
    bool Active; // Is particle Active
    int Age; // Age of the particle
    int MaxAge; // Maximum Age before particle dies
    int BounceCount;
} Particles[MAX_PARTICLES];

void Init_Particles();
void Activate_Particles();
void Adjust_Particles();
void Render_Particles();
void prepare_GLscene();
void DrawGLscene();
void Reshape(GLsizei w, GLsizei h);


int main(int argc, char** argv){
    glutInit(&argc,argv);
    glutCreateWindow("Particle fountain");
    prepare_GLscene();
    glutDisplayFunc(DrawGLscene);
    //glutReshapeFunc(Reshape);
    glutMainLoop();
}


void Init_Particles(){
    int p;
    srand((int)time(NULL));
    for(p=0; p<MAX_PARTICLES; p++){
        Particles[p].Active = false;
        Particles[p].tX = 0.0f;
        Particles[p].tY = -0.1f;
        Particles[p].tZ = 0.0f;
    }
}

void Activate_Particles(){
    int p;
    for(p=0; p<MAX_PARTICLES; p++){
        if(!Particles[p].Active){
            // Start the particle at 0,0,0 origin
            Particles[p].X = 0.0f;
            Particles[p].Y = 0.0f;
            Particles[p].Z = 0.0f;
            // The following lines set a random speed value
            Particles[p].sX = (((float)((rand() % 100) + 1)) /
                1000.0f) - 0.05f;
            Particles[p].sY = (((float)((rand() % 100) + 50)) /
                500.0f);
            Particles[p].sZ = (((float)((rand() % 100) + 1)) /
                1000.0f) - 0.05f;
            // We also activate the particle
            Particles[p].Active = true;
            // Set it's Age to zero
            Particles[p].Age = 0;
            // We also assign a max age to the particles
            Particles[p].MaxAge = MAX_PARTICLE_AGE;
            // We Also reset the bouncecount to zero
            Particles[p].BounceCount = 0;
            return;
        }
    }
}

void Adjust_Particles(){
    int p;
    for(p=0; p<MAX_PARTICLES; p++){
        // We move the speed towards the target speed by 1/20 (5%)
        Particles[p].sX+= (Particles[p].tX - Particles[p].sX) / 20.0f;
        Particles[p].sY+= (Particles[p].tY - Particles[p].sY) / 20.0f;
        Particles[p].sZ+= (Particles[p].tZ - Particles[p].sZ) / 20.0f;
        // Then we adjust the position of
        // the particle by the new speed
        Particles[p].X+= Particles[p].sX;
        Particles[p].Y+= Particles[p].sY;
        Particles[p].Z+= Particles[p].sZ;
        // Now for the bounce code.
        if(Particles[p].Y < 0.0f){
            Particles[p].Y = 0.0f;
            Particles[p].sY = -Particles[p].sY;
            Particles[p].BounceCount++;
            if(Particles[p].BounceCount > MAX_BOUNCE_COUNT){
                Particles[p].Active = false;
            }
        }
        // And finally the age check
        Particles[p].Age++;
        if(Particles[p].Age > Particles[p].MaxAge){
            Particles[p].Active = false;
        }
}
}

void Render_Particles(){
    int p;
    glBegin(GL_POINTS);
    for(p=0; p<MAX_PARTICLES; p++){
        if(Particles[p].Active){
            glColor4f(1.0f, 1.0f, 1.0f, 0.5f);
            glVertex3f(Particles[p].X,
                Particles[p].Y,
                Particles[p].Z);
        }
    }
    glEnd();

}

void prepare_GLscene(){
    Activate_Particles();
    Adjust_Particles();
    Render_Particles();
}

void DrawGLscene(){
    glTranslatef(0.0f, -0.05f, 0.0f);
    Render_Particles();
    glFlush();
}

void Reshape(GLsizei w,GLsizei h){
    // resize viewport to new canvas size
    glViewport(0, 0, w, h);
    // change clipping region to have same w:h ratio as canvas
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    if (w <= h)
        gluOrtho2D(-1.0, 1.0, -1.0 * h/w, 1.0 * h/w);
    else
        gluOrtho2D(-1.0 * w/h, 1.0 * w/h, -1.0, 1.0);
}