Increase float certain time period?

Question

I am trying to create a somewhat easy of a method for my game however I am not quite sure how to implement it. I have a float right now that starts at .1, I would like it to increment to 1 in a certain time frame.

Lets say this time frame was .5 seconds. Now clearly this method would be called on an update loop to increase it every time however I am not sure where to begin.

I hate to post a question without any code but I just don't know the logistics of it. Would I divide the result number by the deltaTime? Any advice would be appreciated.

Answer 1

If this float is a property of a CCNode descendant, try CCActionTween : here is the excerpt from the docs (version 2.1):

 /** CCActionTween

 CCActionTween is an action that lets you update any property of an object.
 For example, if you want to modify the "width" property of a target from 200 to 300 in 2     
 seconds, then:

 id modifyWidth = [CCActionTween actionWithDuration:2 key:@"width" from:200 to:300];
 [target runAction:modifyWidth];

 Another example: CCScaleTo action could be rewriten using CCPropertyAction: (sic) CCActionTween

// scaleA and scaleB are equivalents
 id scaleA = [CCScaleTo actionWithDuration:2 scale:3];
 id scaleB = [CCActionTween actionWithDuration:2 key:@"scale" from:1 to:3];

 @since v0.99.2
 */

EDIT :

Example : say you have a Cannon class, which derives from CCNode (as in the .h below)

@interface Cannon:CCNode {

    float _bulletInitialVelocity;
    float _firingRate;
}

@property (nonatomic, readwrite) float bulletInitialVelocity;
@property (nonatomic, readwrite) float firingRate;
@end

in the cannon logic, you could

CCTweenAction *fr = [CCTweenAction actionWithDuration:60.0 key:@"firingRate" from:.25 to:.75];
[self runAction:fr];

this could increase the firing rate over a period of 60 seconds. You could do the same for bullet's initial velocity. Notice these properties are not CCNode properties, but some you created yourself by extending CCNode. I wrote it old style so you can see that the properties are actually 'backed' by an iVar.