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Ghoti
Joined: 31 Dec 2005
Posts: 288
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 Posted: Thu May 24, 2007 8:08 pm Post subject: analog stick acts wierd. |
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Hi folks,
is it standard PSP behaviour with programming only that the analog stick tends to go left without reason (i guess not so here is the code) can someone tell me what i do wrong ?
| Code: | movement = (float)(pad.Lx)-128.0f;
if (movement < 20.0f && movement > -20.0f) { movement = 0.0f;}
else if (movement < 100.0f && movement > -100.0f) {
if (movement < 0) { movement = -0.01f;}
else { movement = 0.01f; }
}
else {
if (movement < 0) {movement = -0.025f;}
else { movement = 0.025f; }
}
player->setRoll(movement, player->rotation.y);
player->setDirection(VectorRotate(player->rotation.y)); |
as yo ucan see i check whether the value is beyond +20 or -20 to cure this problem for the most part but sometimes it still turns left automatically :S i can make the marge larger but then the death spot of the analog control gets to big i guess?
anyone got some solution ?
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My PSP games:
Boxy II: http://www.ghoti.nl/boxyii.php
Elementals: http://www.ghoti.nl/Elementals.php |
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Brunni
Joined: 08 Oct 2005
Posts: 186
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| Posted: Thu May 24, 2007 8:20 pm Post subject: |
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The analog stick is.... analog :p that is, not very precise.
You have to take in account a minimal treshold. The stick will never be at (0, 0). The weirdest is that it doesn't have a "dead zone", its value depend from the direction you moved it last time, but it should always be in a range of +/- 32 when it's released (or more on some PSP, I don't know).
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Sorry for my bad english
 Oldschool library for PSP - PC version released |
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Ghoti
Joined: 31 Dec 2005
Posts: 288
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| Posted: Fri May 25, 2007 11:57 pm Post subject: |
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ah yes well i had it on ±20 but now i have set it on 32 and it is a lot better now :D thanks for the info but i do like to know why exactly this is and why it is such a big number. I mean can't they make analog precise or is it to expensive?
| Quote: | | depend from the direction you moved it last time |
so when i press it to the max left and then a little to the right it will give info that you move right instead of less left ?
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My PSP games:
Boxy II: http://www.ghoti.nl/boxyii.php
Elementals: http://www.ghoti.nl/Elementals.php |
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Cy-4AH
Joined: 31 Jan 2007
Posts: 44
Location: Belarus
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| Posted: Sat May 26, 2007 12:07 am Post subject: |
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No, it will give max left minus little to the right.
Why you don't try sample from pspsdk witch display analog status?
It's placed at pspdev\psp\sdk\samples\controller\basic |
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Brunni
Joined: 08 Oct 2005
Posts: 186
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| Posted: Sat May 26, 2007 1:53 am Post subject: |
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My english is not good, and so my explanations are :p
You'll see what I'm talking about when trying the analog sample :)
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Sorry for my bad english
Oldschool library for PSP - PC version released |
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mc
Joined: 12 Jan 2005
Posts: 212
Location: Linköping
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| Posted: Sat May 26, 2007 5:25 am Post subject: |
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| Ghoti wrote: | | I mean can't they make analog precise or is it to expensive? |
The analog stick is of a very simple construction. The stick itself is fixed
to a small plastic disc, which rests inside of a circular coil spring. The
spring is suspened around a plastic ridge, that the disc can slide under,
but not the spring. (See the diagram below.) When you push the stick in
some direction, the disc will slide out under the ridge, dislocating a part
of the spring. Since the other side of the spring is suspended by the
ridge, the spring can't follow the disc by simple translation, and will
instead stretch to fit around the disc. This tightens the spring, producing
a force to pull back the disc (and thus the stick) when you let go.
However, as the disc slides back, the spring contracts, resulting in less
and less force being applied. When the stick has reached a certain
point (+20, or whatever), there spring will have contracted so much that
there is not enough stored force left to overcome the friction between the
disc and the ridge. So the lack of good centering is the result of cheap
design. Not _bad_ design, just cheap.
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Ghoti
Joined: 31 Dec 2005
Posts: 288
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