hello list,
      i'm pretty new to opengl programming and i have a billion dollar question. I have a particle system running and i draw every particle with opengl

1.    gl.glBegin(GL.GL_POINTS);        
         gl.glColor4f(1,1, 1,.5);
         gl.glVertex2f(p[i].position().x(), p[i].position().y());
2.       gl.glEnd();

were p[i].position().x(), p[i].position().y() are the x,y position of my particles.

I'm drawing my particles in white over black background.

now I'd like to have a fancy effect in my sketch putting on top  in "multiply" blending mode a texured quad.

1. maskTexture.bind();
     maskTexture.enable();
     gl.glBegin(GL.GL_QUADS);
     gl.glNormal3f( 0.0f, 0.0f, 1.0f);
     gl.glTexCoord2f(0, 0);
     gl.glVertex2f(0, 0);
     gl.glTexCoord2f(1, 0);
     gl.glVertex2f(width, 0);
     gl.glTexCoord2f(1, 1);
     gl.glVertex2f(width, height);
     gl.glTexCoord2f(0, 1);
     gl.glVertex2f(0,height);
     gl.glEnd(); 
   
     maskTexture.disable();
   

were maskTexture is a jpg with a gradient color.
The effect is done by   gl.glBlendFunc(GL.GL_ZERO, GL.GL_SRC_COLOR);

the result is:


i like the result BUT THE PERFORMANCE IS SIGNIFICANTLY REDUCED. I know every cycle cpu have to calculate the blending on all screen, but

there is a way to speed up the rendering?

thanks a lot.