I am working with OpenGL ES 2.0 and ARToolKitPlus. From the ARTK+ I get a transformation matrix to rotate and scale the openGL model into the coordinates of the marker.
The problem is that, for some unknown reason, the rotations are inverted. So, the object rotate clockwise around the X axis while it was supposed to rotate counter clockwise. So, I should invert the matrix, but I do not know how to do it.
The other option is to calculate the transformation myself. To do so, I should calculate a 3D transformation for the openGL model from the 2D coordinates (coordinates on the screen) I get from the marker. I know the size of the marker, its 4 vertex and the center.
Anyone can help me in any of both solutions?
Thanks in advance!!