private void drawLine(int X1, int Y1, int X2, int Y2, float color[]) {
    GL11.glColor3f(color[0], color[1], color[2]);

    GL11.glBegin(GL11.GL_LINES);
    GL11.glVertex2f(X1, Y1);
    GL11.glVertex2f(X2, Y2);
    GL11.glEnd();
  }
  private void drawVecSlider() {
    drawQuad(screenWidth - 205, 0, 200, 205, colorArray[3]);
    drawQuad(screenWidth - 200, 5, 190, 195, colorArray[0]);

    drawQuad(screenWidth - 101, 70, 60, 2, colorArray[4]);
    drawQuad(screenWidth - 130, 99, 2, 60, colorArray[4]);

    GL11.glTranslatef(screenWidth - 100, 100, 0);

    drawCircle(vecSlider.x, vecSlider.y, 11, colorArray[2]);

    GL11.glLoadIdentity();

    // drawCircle((sizeSliderVal*7) + 23, 30, 25, colorArray[2]);
  }
  private void drawCircle(double x, double y, int radius, float color[], float alpha) {
    GL11.glColor4f(color[0], color[1], color[2], alpha);

    float incr = (float) (2 * Math.PI / slices);
    /*xCoord = xCoord + radius;
    yCoord = yCoord + radius;*/

    GL11.glBegin(GL11.GL_TRIANGLE_FAN);
    for (int i = 0; i < slices; i++) {
      float angle = incr * i;

      float Xc = (float) (x + Math.cos(angle) * radius);
      float Yc = (float) (y + Math.sin(angle) * radius);

      GL11.glVertex2f(Xc, Yc);
    }
    GL11.glEnd();
  }
 static void drawTorus(float r, float R, int nsides, int rings) {
   float ringDelta = 2.0f * (float) Math.PI / rings;
   float sideDelta = 2.0f * (float) Math.PI / nsides;
   float theta = 0.0f, cosTheta = 1.0f, sinTheta = 0.0f;
   for (int i = rings - 1; i >= 0; i--) {
     float theta1 = theta + ringDelta;
     float cosTheta1 = (float) Math.cos(theta1);
     float sinTheta1 = (float) Math.sin(theta1);
     GL11.glBegin(GL11.GL_QUAD_STRIP);
     float phi = 0.0f;
     for (int j = nsides; j >= 0; j--) {
       phi += sideDelta;
       float cosPhi = (float) Math.cos(phi);
       float sinPhi = (float) Math.sin(phi);
       float dist = R + r * cosPhi;
       GL11.glNormal3f(cosTheta1 * cosPhi, -sinTheta1 * cosPhi, sinPhi);
       GL11.glVertex3f(cosTheta1 * dist, -sinTheta1 * dist, r * sinPhi);
       GL11.glNormal3f(cosTheta * cosPhi, -sinTheta * cosPhi, sinPhi);
       GL11.glVertex3f(cosTheta * dist, -sinTheta * dist, r * sinPhi);
     }
     GL11.glEnd();
     theta = theta1;
     cosTheta = cosTheta1;
     sinTheta = sinTheta1;
   }
 }
  private void drawQuad(int x, int y, int h, int w, float color[], float alpha) {
    GL11.glColor4f(color[0], color[1], color[2], alpha);

    // draw quad
    GL11.glBegin(GL11.GL_QUADS);
    GL11.glVertex2f(x, y);
    GL11.glVertex2f(x + w, y);
    GL11.glVertex2f(x + w, y + h);
    GL11.glVertex2f(x, y + h);
    GL11.glEnd();
  }
  private void startDisplayLoop() {
    while (!Display.isCloseRequested()) {
      GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);

      checkInput();
      applyPhysics();

      drawStuff();

      endThisLoop();
    }
    endProgram();
    Display.destroy();
  }
  private void initGL(int width, int height) {

    try {
      // DisplayMode mode = new DisplayMode(width,height);
      // DisplayMode mode = Display.getDesktopDisplayMode(); Old code, for not-fullscreen stuff
      Display.setDisplayMode(Display.getDesktopDisplayMode());
      Display.setFullscreen(true);
      Display.create();
      Display.setVSyncEnabled(true);
    } catch (LWJGLException e) {
      System.out.println("Catched an error in intiGL");
      e.printStackTrace();
      System.exit(0);
    }

    // init OpenGL
    GL11.glMatrixMode(GL11.GL_PROJECTION);
    GL11.glLoadIdentity();
    GL11.glOrtho(0, width, 0, height, 1, -1);
    GL11.glMatrixMode(GL11.GL_MODELVIEW);

    GL11.glEnable(GL11.GL_BLEND);
    GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
  }
  public static void main(String[] args) {
    final Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new FillLayout());
    Composite comp = new Composite(shell, SWT.NONE);
    comp.setLayout(new FillLayout());
    GLData data = new GLData();
    data.doubleBuffer = true;
    final GLCanvas canvas = new GLCanvas(comp, SWT.NONE, data);

    canvas.setCurrent();
    try {
      GLContext.useContext(canvas);
    } catch (LWJGLException e) {
      e.printStackTrace();
    }

    canvas.addListener(
        SWT.Resize,
        event -> {
          Rectangle bounds = canvas.getBounds();
          float fAspect = (float) bounds.width / (float) bounds.height;
          canvas.setCurrent();
          try {
            GLContext.useContext(canvas);
          } catch (LWJGLException e) {
            e.printStackTrace();
          }
          GL11.glViewport(0, 0, bounds.width, bounds.height);
          GL11.glMatrixMode(GL11.GL_PROJECTION);
          GL11.glLoadIdentity();
          GLU.gluPerspective(45.0f, fAspect, 0.5f, 400.0f);
          GL11.glMatrixMode(GL11.GL_MODELVIEW);
          GL11.glLoadIdentity();
        });

    GL11.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
    GL11.glColor3f(1.0f, 0.0f, 0.0f);
    GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST);
    GL11.glClearDepth(1.0);
    GL11.glLineWidth(2);
    GL11.glEnable(GL11.GL_DEPTH_TEST);

    shell.setText("SWT/LWJGL Example");
    shell.setSize(640, 480);
    shell.open();

    final Runnable run =
        new Runnable() {
          int rot = 0;

          @Override
          public void run() {
            if (!canvas.isDisposed()) {
              canvas.setCurrent();
              try {
                GLContext.useContext(canvas);
              } catch (LWJGLException e) {
                e.printStackTrace();
              }
              GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
              GL11.glClearColor(.3f, .5f, .8f, 1.0f);
              GL11.glLoadIdentity();
              GL11.glTranslatef(0.0f, 0.0f, -10.0f);
              float frot = rot;
              GL11.glRotatef(0.15f * rot, 2.0f * frot, 10.0f * frot, 1.0f);
              GL11.glRotatef(0.3f * rot, 3.0f * frot, 1.0f * frot, 1.0f);
              rot++;
              GL11.glPolygonMode(GL11.GL_FRONT_AND_BACK, GL11.GL_LINE);
              GL11.glColor3f(0.9f, 0.9f, 0.9f);
              drawTorus(1, 1.9f + ((float) Math.sin((0.004f * frot))), 15, 15);
              canvas.swapBuffers();
              display.asyncExec(this);
            }
          }
        };
    canvas.addListener(SWT.Paint, event -> run.run());
    display.asyncExec(run);

    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) display.sleep();
    }
    display.dispose();
  }
 private void endProgram() {
   GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
   System.exit(0);
 }