cocos2d for iPhone

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

1. 

   zombie
   Member

   Hi,

   I want to rotate a sprite around its y-axis. To do this I have overwritten the transform method like shown below.
   It is working, but the rotation added by me does not rotate exactly around the y-axis and the center of the sprite. I tried to do the rotation at different positions of the translate method, but with no luck.

   Any help on this would be great,
   zombie

   if ( relativeAnchorPoint_ && (transformAnchor_.x != 0 || transformAnchor_.y != 0 ) )
   	glTranslatef( RENDER_IN_SUBPIXEL(-transformAnchor_.x), RENDER_IN_SUBPIXEL(-transformAnchor_.y), vertexZ_);
   
   if (transformAnchor_.x != 0 || transformAnchor_.y != 0 )
   	glTranslatef( RENDER_IN_SUBPIXEL(position_.x + transformAnchor_.x), RENDER_IN_SUBPIXEL(position_.y + transformAnchor_.y), vertexZ_);
   else if ( position_.x !=0 || position_.y !=0)
   	glTranslatef( RENDER_IN_SUBPIXEL(position_.x), RENDER_IN_SUBPIXEL(position_.y), vertexZ_ );	
   
   // ADDED
   // ADDED
   // ADDED
   glRotatef( -50.0f, 0.0f, 1.0f, 0.0f );
   
   // rotate
   if (rotation_ != 0.0f )
   	glRotatef( -rotation_, 0.0f, 0.0f, 1.0f );
   
   // scale
   if (scaleX_ != 1.0f || scaleY_ != 1.0f)
   	glScalef( scaleX_, scaleY_, 1.0f );
   
   // restore and re-position point
   if (transformAnchor_.x != 0.0f || transformAnchor_.y != 0.0f)
   	glTranslatef(RENDER_IN_SUBPIXEL(-transformAnchor_.x), RENDER_IN_SUBPIXEL(-transformAnchor_.y), vertexZ_);

   Posted 2 years ago #
2. 

   bradparks
   Member

   I don't know if it would work for you or not, but doesn't the "OrbitCamera" action do something like that? Maybe it's not the same thing though as what you're trying to achieve?

   http://www.cocos2d-iphone.org/api-ref/latest-stable/interface_orbit_camera.html

   and even it if doesn't do exactly what you want, it might have some code in it that'd point you in the right direction....

   or maybe even the "FlipY3d" action?

   http://www.cocos2d-iphone.org/api-ref/latest-stable/interface_flip_y3_d.html

   I haven't used either of them though... just thought I remembered them doing something like that!

   Posted 2 years ago #
3. 

   zombie
   Member

   I think I know what the problem is.

   My rotated 2d-sprite is not looking the same when moving around the layer it is located on. Its like I am moving in a 3D scene.

   Is there a gl option or whatever to display everything wihtout depth? I do not know how to explain this. I want my scene look like it is projected on a 2D plane.

   I look it up at wiki and I think I want a Orthographic projection.

   zombie

   Posted 2 years ago #
4. 

   zombie
   Member

   ok I can do what I want with glOrthof, but I have no idea how. Would it be best to set this for the complete scene? Where do I add this?

   Posted 2 years ago #
5. 

   zombie
   Member

   ok, solved it myself :)

   I set the default projection of the Director to CCDirectorProjection2D.

   - zombie

   Posted 2 years ago #
6. 

   oscarmk
   Member

   Hi zombie I am having the same problem but doing:

   [[Director sharedDirector] setProjection:CCDirectorProjection2D];

   I just realized that you have to set this per Scene. It is a 2D projection now.

   Posted 2 years ago #
7. 

   pabloruiz55
   Member

   Hi!
   I am trying to do the same thing and i haven't been able.
   I use

   CCOrbitCamera * orbit = [CCOrbitCamera actionWithDuration:2 radius:1 deltaRadius:0 angleZ:0 deltaAngleZ:360 angleX:0 deltaAngleX:0];
   [self runAction:orbit];

   to flip an sprite on its X axis but i haven't been able to do it on its Y axis. Any pointers?

   I need to simulate like the sprite was getting up, sort of a dummy in a shooting range.

   Thanks!

   Posted 12 months ago #
8. 

   Birkemose
   Member

   Couldnt you just tinker with the scaleX property of the sprite?
   If you adjust it according to a sinf, it should look like a flat object turning.

   Posted 12 months ago #
9. 

   pabloruiz55
   Member

   Hi @birkemose, thanks! I did manage to do what i originally needed by tweaking the CCOrbitCamera action but it didn't look good since the flipping occurred in its center and i had no clue how to make it happen in its bottom.

   I ended up doing what you suggested (without the sinf since i couldn't think of it) and also applying some movement. Looks pretty good. Thanks!

   Posted 12 months ago #

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