quartz 2d / openGl / cocos2d image distortion in iphone by moving vertices for 2.5d iphone game

We are trying to achieve the following in an iphone game:

Using 2d png files, set-up a scene that seems 3d. As the user moves the device, the individual png files would warp/distort accordingly to give the effect of depth.

example of a scene: an empty room, 5 walls and a chair in the middle. = 6 png files layered.

We have successfully accomplished this using native functions like skew and scale. By applying transformations to the various walls and the chair, as the device is tilted moved, the walls would skew/scale/translate . However, the problem is since we are using 6 png files, the edges dont meet as we move the device. We need a new solution using a real engine.

Question:

we are thinking of instead of applying skew/scale transformations, that if given the freedom to move the vertices of t开发者_开发百科he rectangular images, we could precisly distort images and keep all the edges 100% aligned.

What is the best framework to do this in the LEAST amount of time? Are we going about this the correct way?

You should be able to achieve this effect (at least in regards to the perspective being applied to the walls) using Core Animation layers and appropriate 3-D transforms.

A good example of constructing a scene like this can be found in the example John Blackburn provides here. He shows how to set up layers to represent the walls in a maze by applying the appropriate rotation and translation to them, then gives the scene perspective by using the trick of altering the m34 component of the CATransform3D for the scene.

I'm not sure how well your flat chair would look using something like this, but certainly you can get your walls to have a nice perspective to them. Using layers and Core Animation would let you pull off what you want using far less code than implementing this using OpenGL ES.

Altering the camera angle is as simple as rotating the scene in response to shifts in the orientation of the device.

If you're going to the effort of warping textures as they would be warped in a 3D scene, then why not let the graphics hardware do the hard work for you by mapping the textures to 3D polygons, then changing your projection or moving polygons around?

I doubt you could do it faster by restricting yourself to 2D transformations --- the hardware is geared up to do 3x3 (well, 4x4 homogenous) matrix multiplication.