java - visual error with adding bullets from a list with lwjgl and openGL with a for loop -

so i'm learning opengl lwjgl , everything's fine until add way shoot. upon pressing space, bullet created , added list of bullets. when go render it, call each bullet's x , y using loop, render using coords, , update of bullets. except when this, player (a green box) gets flashy , doesn't move (visually) , bullets never disappear screen , instead move downward leaving "ghost trail". can, however, move player without moving green box, because when move him , right little can create new ghost trail of bullets , right second.

bullet.java:

package game; import java.util.arraylist; import java.util.list;   public class bullet {   public int speed;   public int x;     public int y;     public char direction;     int origin;     public static final int player_origin = 0;     public static final int monster_origin = 1;     static list<bullet> bullets = new arraylist<bullet>();     public static void dotick(){         for(int = 0; < bullets.size(); i++){             //moves bullets based on speed , direction             if(bullets.get(i).direction == 'w'){                 bullets.get(i).y -= bullets.get(i).speed;             } else if(bullets.get(i).direction == 'a'){                 bullets.get(i).x -= bullets.get(i).speed;             } else if(bullets.get(i).direction == 's'){                 bullets.get(i).y += bullets.get(i).speed;             } else if(bullets.get(i).direction == 'd'){                 bullets.get(i).x += bullets.get(i).speed;             }         }     }     public bullet(int x, int y, char newdirection, int neworigin){         direction = newdirection;         speed = 6;         if(neworigin == player_origin){             if(direction == 'w' ){                 x= x + 16;                 y= y;             } else if (direction == 'd'){                 x= x + 32;                 y= y + 16;             } else if (direction == 'a'){                 x= x;                 y= y + 16;             } else if(direction == 's'){                 x= x + 16;                 y= y + 32;             }         }      } } 

game.java:

package game; import javax.swing.*; import java.util.arraylist; import java.awt.*; import java.awt.event.actionevent; import javax.swing.timer; import java.awt.event.*; import java.util.list; import org.lwjgl.lwjglexception; import org.lwjgl.input.keyboard; import org.lwjgl.opengl.display; import org.lwjgl.opengl.displaymode; import static org.lwjgl.opengl.gl11.*; @suppresswarnings({ "serial" }) public class game{   static player player = new player(10,10);     timer timer;     boolean wp;     boolean ap;     boolean sp;     boolean dp;     boolean spp;     int xp;     int yp;      public static void main(string[] args){          game game = new game();         game.start();     }     private void start(){         //initialize display         try {             display.setdisplaymode(new displaymode(800,600));             display.create();         } catch (lwjglexception e) {             e.printstacktrace();         }         //initialize opengl         glmatrixmode(gl_projection);         glloadidentity();         glortho(0,display.getwidth(),0,display.getheight(), -1, 1);         glmatrixmode(gl_modelview);         glclearcolor(0,0,0,1);         gldisable(gl_depth_test); //no 3d         //game loop         while(!display.iscloserequested()){             glclear(gl_color_buffer_bit);              glcolor3f(0.25f,0.75f,0.5f);              glbegin(gl_quads);             {                 glvertex2f(xp, yp);                 glvertex2f(xp, 64 + yp);                 glvertex2f(64 + xp, 64 + yp);                 glvertex2f(64 + xp, yp);             }             glend();             for(int = 0; < bullet.bullets.size(); i++){                 glbegin(gl_quads);                 glvertex2f(bullet.bullets.get(i).x, bullet.bullets.get(i).y);                 glvertex2f(bullet.bullets.get(i).x, 4 + bullet.bullets.get(i).y);                 glvertex2f(4 + bullet.bullets.get(i).x, bullet.bullets.get(i).y);                 glvertex2f(4 + bullet.bullets.get(i).x, 4 + bullet.bullets.get(i).y);             }             display.update();             if(keyboard.iskeydown(keyboard.key_w)){                 yp += 10;             }             if(keyboard.iskeydown(keyboard.key_a)){                 xp -= 10;             }             if(keyboard.iskeydown(keyboard.key_s)){                 yp -= 10;             }             if(keyboard.iskeydown(keyboard.key_d)){                 xp += 10;             }             if(keyboard.iskeydown(keyboard.key_space)){                 bullet tempbullet = new bullet(xp+32, yp+32, 'w', bullet.player_origin); //creates temporary bullet based on player                 bullet.bullets.add(tempbullet); //adds bullet static list of bullets in bullet.java             }             bullet.dotick();          }         display.destroy();     } } 

a glend(); after drawing each bullet might help.

also, unrelated, can put glbegin/glend on outside of loop.