I am writing a fragment shader for a tile set. In the shader I have the UV coordinates of the whole texture, however, I am interested in the UV coordinates of the current tile that is being rendered. In other words: in my shader I am interested to know where the current pixel is within the current tile, not within the whole texture.
So given the overall texture size and the rectangle that defines the tile to render within that texture, and given the UV coordinates of the current pixel corresponding to the whole texture, how can I convert these UV coordinates to the "inner" UV coordinates of the current tile, but also in the range of [0.0,1.0]?
