cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   Bongeh
   Member

   Hey guys,

   I'm looking for guidance here, not a straight forward answer, (unless its easy and not too much hassle for you), i've looked into the ccDrawCircle method and have managed to make it draw a solid circle, i also understand that the circle is drawn by connecting lots of vertex's.

   My aim is to create a 'cone of vision' for an enemy guard, given a degree or even a radian.

   So for example, i'd want to call a method saying something along the lines of drawCircleSegmentFor:(float)degrees

   Could anyone give me a hand here, links to reading materials or tutorials to do with this sort of thing.

   (I have tried to google openGL drawing tutorials and alike but feel like i'm jumping into the deepest part of the ocean, i'm struggling to find a starting point to my learning.)

   Thanks in advance guys.

   Posted 1 year ago #
2. 

   Benihana
   Member

   I don't have the answer to your direct question, but have you considered a sprite instead of a primitive draw call? You could rotate it with the sprite, or independently, and have it fade into the distance or on the sides to indicate peripheral. You could also invert it, so that whatever is not inside the line of sight has a "fog" over it (partially transparent if you wish), or do what Warcraft et. al. does and only show your tilemap within the fog.

   Posted 1 year ago #
3. 

   mobilebros
   Moderator

   @Bongeh - I think it might be relatively easy...

   Try this, find this line in ccDrawCircle:

   const float coef = 2.0f * (float)M_PI/segs;

   and below it type in:

   coef *= (a2-a)/(M_PI*2.0f);

   The 'a2' variable would be another argument to the function, it would represent your "end" angle.

   I haven't tested it; I think you'll need drawLineToCenter to be true; perhaps it might not draw the first segment either... let me know what you see, good luck.

   Posted 1 year ago #
4. 

   Birkemose
   Moderator

   cocos ( ofcause ) have a class that can carve out a circular percentage of a sprite
   check out CCProgressTimer

   What I would do is to make a circular sprite, and then using CCProgressTimer cut it to the guards view.
   The rest is opacity, color, rotation and ... well... the rest ...

   In the NightFlight video I posted yesterday, you can see the "cooldown" buttons use the CCProgressTimer

   Posted 1 year ago #
5. 

   Bongeh
   Member

   Thanks for your replys guys, I completely forgot about the CCProgressTimer!, ill check out the code you'd suggested too mobilebros.

   I'll post my efforts in a few days (hopefully with a working solution ^^ )

   Posted 1 year ago #

RSS feed for this topic

Reply

You must log in to post.