GlAccum для FBO? Помощь для изменения

Я смотрел этот пример в Интернете о том, как получить след движения по точкам, но не могу понять, что я должен использовать вместо буфера glAccum, чтобы использовать след.

Я только начал изучать фреймбуферы, и эти устаревшие функции не делают это проще.

void drawGLScene ()
{
// Они рассчитывают наш fps … (помните: статические переменные назначаются только один раз!)
статический GLint t0 = 0;
статические кадры GLint = 0;

// Clear the draw and depth buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// Take the contents of the current accumulation buffer and copy it to the colour buffer with each pixel multiplied by a factor
// i.e. we clear the screen, draw the last frame again (which we saved in the accumulation buffer), then draw our stuff at its new location on top of that
glAccum(GL_RETURN, 0.95f);

// Clear the accumulation buffer (don't worry, we re-grab the screen into the accumulation buffer after drawing our current frame!)
glClear(GL_ACCUM_BUFFER_BIT);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

// Translate everything into the screen (z-axis) by -windowDepth
glTranslatef(0.0f, 0.0f, -windowDepth);

// Apply oscillating rotation to the matrix around the Z-axis.
// Multiplying by 100 is just a fudge factor to increase the total rotation amount
glRotatef(cos(deg2rad(Star::rotationAmount)) * 100, 0.0f, 0.0f, 1.0f);

vector<Star>::iterator starIter; // This needs to be a standard iterator not a constant iterator so we can modify what's being pointed to!!

// Do the actual drawing...
for (starIter = stars.begin(); starIter != stars.end(); starIter++)
{
// Change the point size to the stars size property
glPointSize(starIter->getStarSize());

glBegin(GL_POINTS); // This needs to be inside the loop so the PointSize change (above) takes effect

// Set the colour
glColor3f(starIter->getRedComponent(), starIter->getGreenComponent(), starIter->getBlueComponent());

// Draw the point
glVertex3f(starIter->getX(), starIter->getY(), starIter->getZ());

glEnd();

// Move the star closer (or reset it if it's too close) ready for the next frame
starIter->moveStar();
}

// Swap the buffers so we can see what we've drawn without -watching- it being drawn
SDL_GL_SwapBuffers();

// Take the contents of the current draw buffer and copy it to the accumulation buffer with each pixel modified by a factor
// The closer the factor is to 1.0f, the longer the trails... Don't exceed 1.0f - you get garbage.
glAccum(GL_ACCUM, 0.9f);

// Calcualate our FPS and display it in the console every five seconds
frames++;
{
GLint t = SDL_GetTicks();
if (t - t0 >= 5000)
{
GLfloat seconds = (t - t0) / 1000.0;
GLfloat fps = frames / seconds;
printf("%d frames in %g seconds = %g FPS\n", frames, seconds, fps);
t0 = t;
frames = 0;
}
}

// Add to the star rotation for the next frame
if (Star::rotationAmount < 360.0f)
{
// How quickly this value goes up will controll how quickly it rotates...
// i.e. higher values == faster rotation
Star::rotationAmount += Star::ROTATION_SPEED;
}
else
{
Star::rotationAmount = 0.0f;
}

}

Я действительно изо всех сил пытаюсь заставить это работать, кто-то помогает!