Well then, it's done.

Please take a look and do the pertinent corrections 

You mean by adding the part that sets the FB objects? If you don't change the render target then it works without that step, in fact if you do that step you get the wrong result.

If I set a vertical offset I get the plane rendered where it should be. But in the texture, it's rendered without the offset. (I can see this after applying the shader, which "crops" the rendering outside that plane).

The offset seems not to be applied when rendering to texture.

Well I finally got the time to struggle a bit with the problem and I think I finally understand the basics of it, with the help of your posts.

Vuforia's native code requests the camera image of my Galaxy Nexus at a resolution of 640x480. Then, to fill the actual display size of my device, it resamples this image taking the width of the screen (1196) as the baseline, which results in a 4:3 resampled video stream of 1196,897 (as opposted to the 1196x720, 16:10 ratio of the actual display).

What I don't understand is the renderToTexture process in JPCT-AE.

In order for both things to match, I create a framebuffer of 1196x897 size (hardcoding the values for this device, just for the sake of simplicity). I then create an NPOT texture of exactly the same size of 1196x897.


Then, on my onDrawFrame, I just render first to texture, then remove the render target and render to the screen. No further processing is done, just rendering first on texture, then on teh screen (I don't have any shaders, just a plane that gets rendered in both the texture and the display). This texture is not used at all anywhere on the code.

Doing this, objects get displaced. Yet if I don't render first to texture, my objects are placed correctly over the target.

Shouldn't the framebuffer (which is "shared" between the texture I render to and the display) be left untouched? I know the plane is untouched, I checked its position before and after rendering to texture and it's exactly the same. How come rendering first to a texture modifies the behavior of later rendering to screen?

Moreso, if I add some other objects to the world, those get displaced to, even if they aren't rendered to the texture.

This is a capture without the rendering to texture:

host images

And this is a screencap after rendering to texture:

image hosting sites

Anyway, following your chain of thought and your advice I tried accounting for this vertical displacement by resizing the fb again after rendering to texture then applying a vertical offset of 177 (897-720) but then I won't see anything on my marker anymore

Thanks, we'll give it a go. I would try to find out a proper solution though, and update it on the wiki.

Honestly, I don't quite get what's happening here "behind the scenes". We already get the fov/fovy values and set them up, but that does not do the trick.

If I create the framebuffer with the width and height from onSurfaceChanged, I get these stretching and shrinking of my objects, even after setting fov and fovy.

If I set the fb resolution values manually, then objects are displaced along x and y axis when I move the device, unless I also set the fov/fovy values, which is the only way they show up properly. I thought that settled it up temporarily at least, until we stumbled across this problem.

Well that does seem like a good reason