Random value

[tonma]

Hi,

 

I'm beginning development on lynx and I don't find a way to get random number with cc65.

 

I've making a flappybird 'test', and I wish to have random y position of column.

 

 

Test only on emulator.

[Turbo Laser Lynx]

This example should randomize between 0 and 15 + 1

result = ((rand() & 0xf) + 1);

Hopefully we will finally get a Lynx port of this fine game

 

Btw. I noticed if you put the number really low, say between 0 and 2 + 1 it's not very reliable and will give the same number over and over.

Edited November 23, 2016 by Turbo Laser Lynx

[+karri]

There is actually two functions to "randomize" things.

void __fastcall__ srand (unsigned seed);

Ths srand function sets a seed for the rand() function.

int rand (void);

The rand() function will return the next "random" number. The sequence is always the same. If you set srand(1) then the function rand() will always return the same random numbers.

 

What I do to get really random numbers is to call rand() all the time from the main loop. In this way it changes by itself as the time passes.

[tonma]

Thanks,

 

It's weird, I'm pretty sure I tested rand() this morning. Anyway, it's works. Never programming with big headache.

 

I'll use rand() in main and maybe a srand(clock()) when I die / restart a level. Thanks too for the range between two numbers

 

 

 

Hopefully we will finally get a Lynx port of this fine game

 

You're serious, you really interested by a flappybird version ?

I'm doing it only for testing the devkit, but finish it doesn't take me too much time. Except for a music, maybe only sound effect like a roaring lynx when you die.

Edited November 23, 2016 by tonma

[Ninjabba]

As a random seed I use a counter based on pressing time of buttons and waiting time in menus and keep feeding this to srand.

 

This will make sure that the sequence of random numbers changes over time.

[Heaven/TQA]

how is the random done in C65?

 

deterministic like you find it at codebase64.org?

[BadPricey]

 

You're serious, you really interested by a flappybird version ?

 

 

Any version of anything on the Lynx is always welcome! ?

Rgds

BadPricey

[+karri]

The rand is a completely deterministic 32 bit sequence. Only 16 bits are returned.

[Turbo Laser Lynx]

You're serious, you really interested by a flappybird version ?

 

Well maybe I was taking it a bit too far when saying it's a *fine game*, but deep inside I've been a bit bummed that there hasn't been a version of it on the Lynx I agree with BadPricey that anything new for the Lynx is nice. Flappy Bird can be pretty fun in small doses at least.

Edited November 24, 2016 by Turbo Laser Lynx

[+karri]

From the docs. The marvellous rand() in cc65:

SEED *= $01010101
SEED += $31415927
SEED = abs(SEED)
return (SEED >>  & $FFFF

The default SEED is 1.

Edited November 24, 2016 by karri

[tonma]

Thanks, I'll continue the game. At least, a playable version with random columns.

 

I can't test on real hardware now. I'm waiting for the multicard SD by Saint.

 

 

The other thing I need is adding sound effect. Hum hum, because for the music I really doesn't understand anything. I mean I can't create music at all. Can we convert with a tracker music files like mod or midi ? Or maybe can we play digitized sound effect. I'm in love of "Let's play awesome golf".

[LX.NET]

Der Luchs light be able to help out. It might be in the new year because he indicated to not code in 2016 anymore. Perhaps he can make an exception for music...

[tonma]

Thank you, I will send him a PM.

 

Without pressure. I am patient