Lately I've been reading about texture filtering, namely Nearest-neighbor filtering, Bilinear filtering, Trilinear filtering, Anisotropic filtering, MIP maps, RIP Maps and so on.

From a high-level perspective I think I can understand these techniques, how the work and why they exist, with the exception of Anisotropic filtering. Anisotropic filtering is driving me nuts.

I can see the problem of having to texturize a surface that is at an angle relative to the camera, but I don't get how sampling trapezoidal footprints could solve this (although I can see the result). This is probably because I DO NOT understand how the trapezoidal footprint is calculated and how the enclosed telexes are weighted to sample the texture.

This article by Nvidia confuses me even more, by using sentences as "when a texel is trapezoidal" or "anisotropic filtering scales either the height or width of a mipmap by a ratio relative to the perspective distortion of the texture". Trapezoidal texel? Scaling a MIPmap? What does this even mean?

Could you help me grasp how AF and AF levels work?

Please note that my goal is NOT to have an OpenGL or DirectX AF implementation, but rather to grasp how AF works from a high-level perspective.

Lately I've been reading about texture filtering, namely Nearest-neighbor filtering, Bilinear filtering, Trilinear filtering, Anisotropic filtering, MIP maps, RIP Maps and so on.

From a high-level perspective I think I can understand these techniques, how the work and why they exist, with the exception of Anisotropic filtering. Anisotropic filtering is driving me nuts.

I can see the problem of having to texturize a surface that is at an angle relative to the camera, but I don't get how sampling trapezoidal footprints could solve this (although I can see the result). This is probably because I DO NOT understand how the trapezoidal footprint is calculated and how the enclosed telexes are weighted to sample the texture.

This article by Nvidia confuses me even more by using sentences as "when a texel is trapezoidal" or "anisotropic filtering scales either the height or width of a mipmap by a ratio relative to the perspective distortion of the texture". Trapezoidal texel? Scaling a MIPmap? What does this even mean?

Could you help me grasp how AF and AF levels work?

Please note that my goal is NOT to have an OpenGL or DirectX AF implementation, but rather to grasp how AF works from a high-level perspective.

Lately I've been reading about texture filtering, namely Nearest-neighbor filtering, Bilinear filtering, Trilinear filtering, Anisotropic filtering, Mip maps, Rip Maps and so on.

From a high-level perspective I think I can understand these techniques, how the work and why they exist, with the exception of Anisotropic filtering. Anisotropic filtering is driving me nuts.

I can see the problem of having to texturize a surface that is at an angle relative to the camera, but I don't get how sampling trapezoidal footprints could solve this (although I can see the result). This is probably because I DO NOT understand how the trapezoidal footprint is calculated and how the enclosed telexes are weighted to sample the texture.

This article by Nvidia confuses me even more, by using sentences as "when a texel is trapezoidal" or "anisotropic filtering scales either the height or width of a mipmap by a ratio relative to the perspective distortion of the texture". Trapezoidal texel? Scaling a MIPmap? What does this even mean?

Could you help me grasp how AF and AF levels work?

Please note that my goal is NOT to have an OpenGL or DirectX AF implementation, but rather to grasp how AF works from a high-level perspective.

Lately I've been reading about texture filtering, namely Nearest-neighbor filtering, Bilinear filtering, Trilinear filtering, Anisotropic filtering, MIP maps, RIP Maps and so on.

From a high-level perspective I think I can understand these techniques, how the work and why they exist, with the exception of Anisotropic filtering. Anisotropic filtering is driving me nuts.

I can see the problem of having to texturize a surface that is at an angle relative to the camera, but I don't get how sampling trapezoidal footprints could solve this (although I can see the result). This is probably because I DO NOT understand how the trapezoidal footprint is calculated and how the enclosed telexes are weighted to sample the texture.

This article by Nvidia confuses me even more, by using sentences as "when a texel is trapezoidal" or "anisotropic filtering scales either the height or width of a mipmap by a ratio relative to the perspective distortion of the texture". Trapezoidal texel? Scaling a MIPmap? What does this even mean?

Could you help me grasp how AF and AF levels work?

Please note that my goal is NOT to have an OpenGL or DirectX AF implementation, but rather to grasp how AF works from a high-level perspective.