1. A method implemented in a processor for texture mapping, the method comprising: inputting at least one texture coordinate as a current texture map position and if filtering based on a projection of a pixel into a texture space is configured: determining texture coordinate partial derivatives; and generating singular values of a Jacobian matrix constructed from the texture coordinate partial derivatives comprising: generating linear combinations of the matrix elements with predefined constant coefficients; forming two two-dimensional vectors from the linear combinations; generating Euclidian norms or approximation of Euclidian norms, from the vectors; and generating singular values as linear combinations of the norms.