I have a map where it uses a hookretrace function. Every time the screen is drawn, it runs some code to randomly determine if it should fill the screen with a bright translucent color (this is to simulate the effect of a thunderstorm and lightning). However, when the color gets filled, it is uneven. Part of the screen will fill and get drawn and a tiny fraction of a second later, the rest will, with the division between the two being some arbitrary horizontal line across the screen.

When I wrote the code 2 years ago, it didn't have this porblem. I originally wrote the code with a computer that had an AMD K6-2. I now have a computer with a dual-core processor. The refresh rate is pretty incredible now, and I am wondering if perhaps the CPU is refreshing the screen faster than my monitor can. Would that be the sort of thing that would cause this to happen? I am pretty sure this is easy to fix by using the timer to keep the refresh rate in check, but I am wondering what causes it in the first place.

Unfortunately I have no internet at home right now and I can't do IRC on my work computer. I can paste in the code, though, it's short. The following is hookretraced:

void trigulweather()

{

  int tw_loop;

  tw_loop=random(0,200);

  setlucent(50);

  if(tw_loop==150)

  {

    rectfill(0,0,639,479,rgb(255,255,128),screen);

  }

  else

  {

    rectfill(0,0,639,479,rgb(0,0,50),screen);

  }

  setlucent(0);

  for(tw_loop=0;tw_loop<10;tw_loop++)

  {

    AdditiveBlit(0+random(0,639-32),0+random(0,479-64),rainstreakgfx,screen);

  }

}

It's just the part where tw_loop=150 that it has problems.

I think this is doing something similar to my 100 Zombies demo. The idea there was to give a night-time effect, punctuated by flashes of red if the player get hurt. It has hookretraced along with all the rest of my hud code.

int overlay_color = 32;   



retraced{

SetLucent(50);  //nightime effect

	if (overlay_color > 32) { overlay_color--; }

	RectFill( 0, 0, 320, 240, RGB(overlay_color, 32, 125), screen);

	SetLucent(0);



}

Then when the player got hit, I could simply change overlay colour to about 255, and the rectfill would be tinted with red that would fade with every passing frame. It would fade faster on a fast machine, but it didn't seem like a problem, except on slow machines where it might take an age to vanish.

I've got a sneaking suspicion this might have something to do with Showpage(); When is the screen actually getting updated?

Actually, I recommend that you don't use ShowPage() in HookRetrace unless you like flickering and wonky updates. The engine's gonna call ShowPage() *again* after the rendering finishes.

Also, that timer loop you got there would highly likely not even be executed, because it's done for at most a 1/100th of a second.

Also, instead of a random chance of lightning, you should have a timestamp variable, that's all like:

if (timer > tw_timestamp)

{

        //// Not shown here: the actual lightning event.

        // Every 1 to 5 seconds, do this again.

        tw_timestamp = timer + Random(100, 500);

}

And then have another timestamp that represents the actual flash effect of the lightning.

So to recap, a timer that tells when to draw lightning again, and another that'll do the lightning fade effect.

And instead of randomly placing rain particles, you'll need to store a position for each of them and update their position in relation to the timer to look nice.

Technetium, if you want I could look at your code in more detail by email (overkill9999 AT gmail DAWT com). But at any rate, don't use pure random drawing, it'll look ugly and super-fast on new machines.

Hopefully this helps.