Dynamically adjusting ambient sound volume

[strazer]

I find it very hard to think of an algorithm to set the sound

Try this:

#define clifftop 135
#define cliffbottom 230

Repeatedly_execute(_always)
  SetChannelVolume(1, (cliffbottom-player.y)/((cliffbottom-clifftop)/255));

[TheMagician]

@Pumaman:
The improvements are greatly apreciated! Thanks!

@Strazer:

Thanks for your work with the algorithm. However there is a fatal exception when that line of script is run ingame (basically as soon as you enter the screen). It says:

"Invalid: Integer devide by zero" .... or something like that ... seems as if (cliffbottom-clifftop)/255)   returns zero? When I type it into my calculator the result is 0.33333  ... perhaps AGS turns that into 0 ?
However, I also tried using (cliffbottom-clifftop)/125) but still the same error message.

Any ideas about that?

[Scorpiorus]

Dividing (cliffbottom-clifftop) by 255 is equal to multiplying (cliffbottom-player.y) by it, with a couple of checks we have:

int volume = (255*(cliffbottom-player.y))/(cliffbottom-clifftop);

if (volume > 255) volume = 255;
else if (volume < 0) volume = 0;

SetChannelVolume(1, volume);

[Gilbert]

Right, to have best results for integer arimetic, always try to arrange the calculations such taht divisions are carried out in the very last steps.

[TheMagician]

Finally it is working!!!!! (and by the way ... completely customizable).

Thanks to all you programming gurus. Thank you very much!

One last thing that came up during this topic:
what is the difference between

int clifftop = 135;

and

#include clifftop 135   ? 

[strazer]

I'm glad it's working now. Thanks a lot, people.

  int clifftop = 135;

declares a variable. But since the value is unlikely to change and this way it takes up memory (insignificant, but still), you can use

  #define clifftop 135

which will replace all instances of "clifftop" in the code with "135" once you compile the game. I don't know the exact term, but I would call it a constant.

[TheMagician]

Thanks strazer!

And thanks again to everybody who contributed.