cocos2d for iPhone

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

1. 

   Alexj17
   Member

   Hey All

   Im using Level Helper and SpriteHelper to create my sprites, images, levels and more importantly animations and physics.

   Note, by physics i mean the debugdraw you can see on the simulator that is used for collision detection.

   I created a swimmer and added physics to this. Done the code so the physics follows the swimmer around the pool as they move. I have now come to animate the swimmer, make the legs kick etc. Now when i load my game and only the first sprite of the animation is the outline for the physics. So i can see the legs kicking on the swimmer but the debugdraw mesh of the physics doesn't animate as well. Now this is not really a problem until for example my swimmer loses their legs (weird game i know). I change the animation to now a swimmer with no legs but again the physics mesh still shows the legs. So any collisions with stuff still happens where the legs were but they shouldnt. This make sense?

   Is there a way to update the physics on the new animation or do i need to remove my whole swimmer and draw a new one?

   Any help at all would be great. Thanks

   Posted 4 months ago #
2. 

   M.O.
   Member

   Remember the physics body and the sprite are separate objects. One alternative is use two separate bodies (and sprites) and connect them with a weld joint.

   Posted 4 months ago #
3. 

   Alexj17
   Member

   Ok, so have the legs have a different 'body' to the swimmers-body body (too many bodies lol). So detect collions with the legs and remove that all together?

   Posted 4 months ago #
4. 

   M.O.
   Member

   Ya, keep them attached with a weld joint. You will have to remove the joint as well though.

   Posted 4 months ago #
5. 

   ibrar006
   Member

   Hi All,
   I have created a monkey animation in Spritehelper. I have created fixtures with each frame of the animation. I uses 1st frame and play animation on that. The problem is that collision is detectable only with 1st frame not with other frames of the animation. Now, I want to dectect collision with each frame of the animation.
   What should I do?
   Please help me.
   Thanks in advance.
   Be happy.

   Posted 4 months ago #
6. 

   jyoung
   Member

   You need to set the active physics body on each frame to match the frame being shown by the animation. It's not too tough to do. You'll override the animation class, and where it sets the new image frame, have it set a new physics body "frame".

   Posted 3 months ago #
7. 

   ibrar006
   Member

   I have no animation class. I just prepare the animation and play it, like
   LHSprite *tiger = [loader spriteWithUniqueName:@"tiger"];
   [tiger prepareAnimationNamed:@"tigerAnimation" fromSHScene:@"tigerSprites"];
   [tiger playAnimation];

   Do you have some code to explain?

   Posted 3 months ago #
8. 

   ibrar006
   Member

   Actually I'm using Spritehelper and Levelhelper combine.
   I need some example code to do..

   Posted 3 months ago #
9. 

   ibrar006
   Member

   please do reply...

   Posted 3 months ago #
10. 

    AppTinker
    Member

    @ibrar006 - Not sure what the problem is, changing the animtion of something doesn't change the body/shape automatically, you should still be getting collisions after the first frame.

    Posted 3 months ago #
11. 

    ibrar006
    Member

    thanks 4 quick reply :)
    I'm using Cocos2d with Box2d(Objective C++). I want to detect collision with each frame of the animation. That animation is created in Spritehelper.
    Could you understand now!

    Posted 3 months ago #
12. 

    ibrar006
    Member

    Dear friends
    What should be the "anchor point" in weld joint?
    thanks in advance :)

    Posted 3 months ago #
13. 

    ibrar006
    Member

    I destroy fixture on body and create a new one, but now body does not detect collision. Here is my code:

    LHSprite *monkey = [loader spriteWithUniqueName:@"monkey1"];
    b2Body *monkeyBody=[monkey body];
    b2Fixture *abc;
    while((abc = monkeyBody->GetFixtureList())){
    monkeyBody->DestroyFixture(abc);
    }
    b2PolygonShape monkeyShape;
    b2Vec2 verts[5];
    verts[0].Set(-1.4f / PTM_RATIO, 256.0f / PTM_RATIO);
    verts[1].Set(-63.6f / PTM_RATIO, 38.2f / PTM_RATIO);
    verts[2].Set(18.4f / PTM_RATIO, -58.0f / PTM_RATIO);
    verts[3].Set(-1.4f / PTM_RATIO, -321.0f / PTM_RATIO);
    verts[4].Set(176.8f / PTM_RATIO, -199.4f / PTM_RATIO);
    monkeyShape.Set(verts, 5);

    b2FixtureDef monkeyFixtureDef;
    monkeyFixtureDef.shape = &monkeyShape;
    monkeyFixtureDef.density = 0.2f;
    monkeyFixtureDef.friction = 0.2f;
    monkeyFixtureDef.restitution = 0.0f;
    monkeyFixtureDef.filter.groupIndex=2;
    monkeyFixtureDef.filter.maskBits=16;
    monkeyFixtureDef.filter.categoryBits=66;
    monkeyFixtureDef.userData=monkey;
    monkeyFixture = monkeyBody->CreateFixture(&monkeyFixtureDef);

    Posted 3 months ago #
14. 

    ibrar006
    Member

    Dudes, I am waiting for your reply...

    Posted 2 months ago #
15. 

    ibrar006
    Member

    Ok my issue is resolved

    Posted 2 months ago #

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