cocos2d for iPhone

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

1. 

   dutchiedave
   Member

   Hi all,

   There seems to be a problem with mapping coordinates either with Cocos3d or PVRShaman. When exporting a model from 3dsmax to a pod file it seems you have to select 'Flip V coordinates' for the mapping to appear correctly in Cocos3d. When this option is selected the pod file mapping is messed up in PVRShaman.

   Conversely if you leave 'Flip V coordinates' unselected it looks messed up in Cocos3d but look correct in PVRShaman.

   Has anyone else noticed this? Is this a bug in the pod loader for Cocos3d?

   Thanks,

   Dave

   Posted 3 months ago #
2. 

   Bill Hollings
   Moderator

   @dutchiedave

   Be sure to read this article on creating POD files for cocos3d.

   Under iOS, all texture files are loaded upside down because of the inverted coordinate systems between OpenGL and UIKit. To compensate, you need to set the Flip V coordinates flag in the POD converter when loading POD files.

   When loading textures onto a parametric (programatically-created non-POD) model, you can use the alignInvertedTextures or flipVertically methods to perform the inversion within cocos3d.

   ...Bill

   Posted 3 months ago #
3. 

   dutchiedave
   Member

   Hi Bill,

   Thanks for your help. Wouldn't it make sense for the pod loader to automatically flip the textures. It shouldn't matter that the Coordinate system is inverted, surely what matters is that a pod file loaded in cocos3d renders the same as pod files loaded in other applications.

   Thank you for your great work.

   Dave

   Posted 3 months ago #
4. 

   Bill Hollings
   Moderator

   @dutchiedave

   Flipping a texture involves changing the texture coordinates of each vertex...which slows loading during runtime. It was not expected that PVRShaman was an issue...so we decided to just let the POD converter flip it during development time.

   However...perhaps we could add a option setting to flip in code during loading for those that want the flexibility. I'll add it to the to-do list.

   Thanks for the suggestion.

   ...Bill

   Posted 3 months ago #
5. 

   dutchiedave
   Member

   Hi Bill,

   It is not just PVRShaman, it is all existing models. Also, and as you support more file formats this will become a bigger problem as Cocos3d won't be able to render any existing models, all model will have to be re-exported specifically for use in Cocos3d.

   Instead of changing every vertex would it be more efficient (or possible) to flip the image that is loaded before applying it to the mesh?

   Thanks,

   Dave

   Posted 3 months ago #

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