I started learning OpenGL ES for Android and i slightly modified the Graphics API example from the SDK
I turned the shape into a rectangle made of a triangle strip and put the texture upon it.
Now what I don't get are two things:
1. the texture coordinates are not what I think they theoretically should be. As far as I understand it,
the coordinates for the lower left, lower right, upper left and upper right corners should be (0,0), (1,0), (0,1), (1,1) respectively.
A texture coordinate asigns a coordinate on the texture to the corresponding coordinate (vertex) on the polygon, doesn't it?
But here in my example, I ended up with these texture coordinates (by trial and error): (0,0),(-1,0),(0,-1),(-1,-1).
In other words, I have to multiply the coords I originally thought correct by -1. If I don't, the texture is applied upside-down.
2. When I rotate the rectangle along the y axis, the texture somehow 'wobbles' in the centre of the rectangle.
I'll attach the project and I'd be reeaally grateful if somebody more knowledgeable in this matter can enlighten me.