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Soloraze
PostPosted: Wed Jun 27, 2012 9:14 pm 
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Joined: Tue May 01, 2012 7:17 pm
Posts: 28
Hi,

my character always goes up, even when i ask him to go down when i click below his position.
For example, when he's at y=30 , and i click at y=12, i would like him to go to y=12 with an impulse :
hero.body->ApplyLinearImpulse( forceOnCharacter*impulseDirection...

But he still goes up. Is it because i'm using "forceOnCharacter" ? (so 12 would become 120 ?) If i remove forceOnCharacter, the player doesn't jump anymore.

Here's my code : (the calcul seems correct (see the output below) )

Code:
- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
   for( UITouch *touch in touches ) {
      CGPoint location = [touch locationInView: [touch view]];
        CGPoint cgp = [[CCDirector sharedDirector] convertToGL: location];
       
        CCLOG(@"hero.position.y: %f, cgp.y-newYPosition: %f", hero.position.y, (cgp.y-newYPosition));
       
        //TOUCH/HERO Y-AXIS
        float diffDist = fabsf(hero.position.y) - fabsf(cgp.y);
        //example: -50(touch), -100(hero), ... or : -100(hero), -150(touch) : calculate diff without the sign
        float finalY;
        if (cgp.y > hero.position.y) finalY = fabsf(diffDist);//if touch above hero.position, impulse == up (+)
        else finalY = (0 - fabsf(diffDist));//else, impulse == down (-)
       
        float heroBodyY = hero.body->GetPosition().y;
       
        CCLOG(@"diffDist: %f, finalY: %f, hero.position.y+finalY: %f", diffDist, finalY, hero.position.y+finalY);
        CCLOG(@"hero.position.y %f, hero.body->GetPosition().y : %f", (hero.position.y)/PTM_RATIO, heroBodyY);
       
        //TOUCH/HERO X-AXIS
        float finalX = cgp.x - hero.position.x;
       
        b2Vec2 impulseDirection = b2Vec2(finalX/PTM_RATIO, (hero.position.y+finalY)/PTM_RATIO);
        impulseDirection.Normalize();
       
        forceOnCharacter = 10 * hero.body->GetMass();
        hero.body->ApplyLinearImpulse( forceOnCharacter*impulseDirection, hero.body->GetPosition() );


and here's the output, when i click above his position, or below, he always goes up :

Quote:
UP
hero.position.y: 293.414215, cgp.y-newYPosition: 423.000000
diffDist: -129.585785, finalY: 129.585785, hero.position.y+finalY: 423.000000
hero.position.y 9.169194, hero.body->GetPosition().y : 9.169194


DOWN //he still goes up
hero.position.y: 409.867218, cgp.y-newYPosition: 61.000000
diffDist: 348.867218, finalY: -348.867218, hero.position.y+finalY: 61.000000
hero.position.y 12.808351, hero.body->GetPosition().y : 12.808351


Thanks for your help
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jayther
PostPosted: Wed Jun 27, 2012 9:58 pm 
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Joined: Sun Oct 25, 2009 3:28 am
Posts: 242
This line looks wrong:
Code:
float diffDist = fabsf(hero.position.y) - fabsf(cgp.y);

That would result in stuff like abs(-50) - abs(50) equaling 0, which is obviously not the difference between -50 and 50.

It should be like this:
Code:
float diffDist = fabsf(hero.position.y - cgp.y);
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Soloraze
PostPosted: Wed Jun 27, 2012 10:51 pm 
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Joined: Tue May 01, 2012 7:17 pm
Posts: 28
Thanks, you're right, but the result is the same, i checked again, but the output seems correct : when i click above (like y=416), the finalY is correct, and hero.position.y+finalY is also correct. Same thing when i click below: the player should go to y=42. But the player still goes up.

Quote:
UP
hero.position.y: 294.703766, cgp.y-newYPosition: 416.000000
newYPosition 0.000000, cgp.y: 416.000000
diffDist: 121.296234, finalY: 121.296234, hero.position.y+finalY: 416.000000


DOWN
hero.position.y: 295.079956, cgp.y-newYPosition: 42.000000
newYPosition 0.000000, cgp.y: 42.000000
diffDist: 253.079956, finalY: -253.079956, hero.position.y+finalY: 42.000000


The code updated : (newYPosition starts when the player goes under the half of the screen in the y-axis)

Code:
for( UITouch *touch in touches ) {
      CGPoint location = [touch locationInView: [touch view]];
        CGPoint cgp = [[CCDirector sharedDirector] convertToGL: location];
       
        CCLOG(@"hero.position.y: %f, cgp.y-newYPosition: %f", hero.position.y, (cgp.y-newYPosition));
        CCLOG(@"newYPosition %f, cgp.y: %f", newYPosition, cgp.y);
       
        //TOUCH/HERO Y-AXIS
        float diffDist = fabsf(hero.position.y - cgp.y);
        //example: -50(touch), -100(hero), -150(touch) : calculate diff without the sign
        float finalY;
        if (cgp.y > hero.position.y) finalY = diffDist;//if touch above hero.position, impulse == up (+)
        else finalY = (0 - fabsf(diffDist));//else, impulse == down (-)
       
        CCLOG(@"diffDist: %f, finalY: %f, hero.position.y+finalY: %f", diffDist, finalY, hero.position.y+finalY);
       
        //TOUCH/HERO X-AXIS
        float finalX = cgp.x - hero.position.x;
       
        b2Vec2 impulseDirection = b2Vec2(finalX/PTM_RATIO, (hero.position.y+finalY)/PTM_RATIO);
        impulseDirection.Normalize();
       
        forceOnCharacter = 10 * hero.body->GetMass();
        hero.body->ApplyLinearImpulse( forceOnCharacter*impulseDirection, hero.body->GetPosition() );


Any other idea?

Thanks
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jayther
PostPosted: Wed Jun 27, 2012 11:30 pm 
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Joined: Sun Oct 25, 2009 3:28 am
Posts: 242
In this line:
Code:
b2Vec2 impulseDirection = b2Vec2(finalX/PTM_RATIO, (hero.position.y+finalY)/PTM_RATIO);


Shouldn't that be finalY-hero.position.y ?

Adding to the hero's position just gives a new destination and does not give a relative direction (or distance).
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Soloraze
PostPosted: Thu Jun 28, 2012 3:37 am 
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Joined: Tue May 01, 2012 7:17 pm
Posts: 28
Thanks, so i fixed a mistake, i had to use cgp.y-newYPosition in all the code instead of cgp.y, and add this condition when cgp.y-newYPosition and hero.position.y are both negative, or only one of the two :

Code:
float diffDist;
        if (hero.position.y<0 && cgp.y-newYPosition<0) {
            diffDist = fabsf(hero.position.y) - fabsf(cgp.y-newYPosition);
            diffDist = fabsf(diffDist);
        }
        else {
           diffDist = fabsf(hero.position.y - cgp.y-newYPosition);
        }


So this works to find the point of destination. But he still only goes up.

I've tried both ways with : hero.position.y+finalY and finalY-hero.position.y, but i'm not sure to understand why you would use finalY-hero.position.y?

Here is the output of my character going up, when i ask him to go below his position : the point of destination is correct (example: -618 and -618), but he still does not want to go down towards this point :

Quote:
3 clicks down, but he always goes up (cgp.y-newYPosition is the point where i clicked) :
hero.position.y: -499.634827, cgp.y-newYPosition: -618.634827,
diffDist: 119.000000, finalY: -119.000000, hero.position.y+finalY: -618.634827, finalY-hero.position.y: 380.634827

hero.position.y: -516.035339, cgp.y-newYPosition: -662.035339,
diffDist: 146.000000, finalY: -146.000000, hero.position.y+finalY: -662.035339, finalY-hero.position.y: 370.035339

hero.position.y: -544.891785, cgp.y-newYPosition: -703.891785,
diffDist: 159.000000, finalY: -159.000000, hero.position.y+finalY: -703.891785, finalY-hero.position.y: 385.891785


Would you know why?

This is my last update :

Code:
- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
   for( UITouch *touch in touches ) {
        CGPoint location = [touch locationInView: [touch view]];   
        CGPoint cgp = [[CCDirector sharedDirector] convertToGL: location];
        b2Vec2 locationWorld = b2Vec2(cgp.x/PTM_RATIO, cgp.y/PTM_RATIO);
       
        float diffDist;
        if (hero.position.y<0 && cgp.y-newYPosition<0) {
            diffDist = fabsf(hero.position.y) - fabsf(cgp.y-newYPosition);
            diffDist = fabsf(diffDist);
        }
        else {
           diffDist = fabsf(hero.position.y - cgp.y-newYPosition);
        }
       
        //Y-AXIS
        float finalY;
        if (cgp.y-newYPosition > hero.position.y) finalY = fabsf(diffDist);//if touch above hero.position, impulse == up (+)
        else finalY = (0 - fabsf(diffDist));//else, impulse == down (-)
       
        //X_AXIS
        float finalX = cgp.x - hero.position.x;
       
        b2Vec2 impulseDirection = b2Vec2(finalX/PTM_RATIO, (finalY-hero.position.y)/PTM_RATIO);
        //b2Vec2 impulseDirection = b2Vec2(finalX/PTM_RATIO, (hero.position.y+finalY)/PTM_RATIO);
        impulseDirection.Normalize();
       
        forceOnCharacter = 10 * hero.body->GetMass();
        hero.body->ApplyLinearImpulse( forceOnCharacter*impulseDirection, hero.body->GetPosition() );
   }
}


Thanks
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jayther
PostPosted: Fri Jun 29, 2012 1:07 am 
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Joined: Sun Oct 25, 2009 3:28 am
Posts: 242
Heh, sorry, I was thinking finalY was an absolute position, not a relative one. So, forget my finalY-hero.position.y suggestion. x]

You don't need to do that whole bit just to get the difference. You only need to do this:
Code:
diffDist = fabsf(hero.position.y - (cgp.y - newYPosition));

And that gives you the difference between the two positions (a positive value).

Anyway, I was thinking why you need to do hero.position.y + finalY, and you don't need to do that for the impulse direction; finalY is already the direction relative to the hero's position. The reason why it goes up is because hero.position.y + finalY will result in an absolute position.

So you only need to do this:
Code:
b2Vec2 impulseDirection = b2Vec2(finalX/PTM_RATIO, finalY/PTM_RATIO);
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Soloraze
PostPosted: Fri Jun 29, 2012 11:54 am 
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Joined: Tue May 01, 2012 7:17 pm
Posts: 28
Quote:
diffDist = fabsf(hero.position.y - (cgp.y - newYPosition));


You're right

Quote:
finalY is already the direction relative to the hero's position


You're right

:mrgreen:

For diffDist, if i click at y=-200, or at y=-600 (if i add his position in the vector) relative to the hero,
It would still be -200 or -600 relative to the position of the hero? I would expect him to go towards -600 instead of -200, but not above his position?

Anyway, thanks for your help :mrgreen:
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