Method and apparatus for angular invariant texture level of detail generation

A method for texture mapping comprising:

• inputting at least one texture coordinate as a current texture map position;
• if mipmapping or anisotropic filtering is configured:
• determining texture coordinate partial derivatives;
• 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;
• if mipmapping is configured:
• if anisotropic filtering is not configured:
• generating an isotropic level of detail (LOD) from a selected singular value from the generated singular values;
• selecting a texture map based upon the LOD;
• updating the current texture map position;
• if anisotropic filtering is configured:
• generating an anisotropic level of detail (LOD) from a selected singular value from the generated singular values;
• selecting a texture map based upon the LOD;
• updating the current texture map position;
• if anisotropic filtering is configured:
• generating an anisotropic ratio and an anisotropic line from singular value decomposition comprising:
• determining the reciprocal of the Euclidian norms;
• creating linear combinations of the reciprocals of the linear combinations and generating two two-dimensional vectors from the linear combinations;
• and
• generating the Euclidean norm of the vectors;
• adding at least one anisotropic offset to update the current texture map position;
• and
• selecting at least one texture mapping data based upon the current texture map position.

A texture unit comprising:

• a partial derivative generator configured to determine texture coordinate partial derivatives;
• a singular value generator configured to generate singular values of a Jacobian matrix constructed from the texture coordinate partial derivatives comprising:
• the singular value generator further configured to generate linear combinations of the matrix elements with predefined constant coefficients;
• the singular value generator further configured to form two two-dimensional vectors from the linear combinations;
• the singular value generator further configured to generate Euclidian norms or approximation of Euclidian norms, from the vectors;
• and
• the singular value generator further configured to generate singular values as linear combinations of the norms
• an anisotropic ratio generator configured to generate an anisotropic ratio from singular values;
• an anisotropic line generator configured to generate an anisotropic line from singular value decomposition comprising:
• the anisotropic line generator further configured to determine the reciprocal of the Euclidian norms;
• the anisotropic line generator further configured to create linear combinations of the reciprocals of the linear combinations and generate two two-dimensional vectors from the linear combinations;
• and
• the anisotropic line generator further configured to generate the Euclidean norm of the vectors;
• a level of detail (LOD) generator configured to generate anisotropic LOD or isotropic LOD;
• a texel fetcher configured to select texels;
• a texel filter configured to filter texels;
• and
• a memory configured to store data comprising at least one of a texel, texture data, or a frame buffer.

A computer readable storage medium comprising:

• a first set of instructions adapted to provide a processor, wherein the processor is configured to implement a second set of instructions, the second set of instructions comprising:
• an input code segment for 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:
• a determination code segment for determining texture coordinate partial derivatives;
• and
• a generation code segment for generating singular values of a Jacobian matrix constructed from the texture coordinate partial derivatives comprising:
• a generation code segment for generating linear combinations of the matrix elements with predefined constant coefficients;
• a formation code segment for forming two two-dimensional vectors from the linear combinations;
• a generation code segment for generating Euclidian norms or approximation of Euclidian norms, from the vectors;
• and
• a generation code segment for generating singular values as linear combinations of the norms.

A computer readable storage medium comprising:

• a first set of instructions adapted to provide a processor, wherein the processor is configured to implement a second set of instructions, the second set of instructions comprising:
• an input code segment for inputting at least one texture coordinate as a current texture map position;
• if mipmapping or anisotropic filtering is configured:
• a determination code segment for determining texture coordinate partial derivatives;
• a generation code segment for generating singular values of a Jacobian matrix constructed from the texture coordinate partial derivatives comprising:
• a generation code segment for generating linear combinations of the matrix elements with predefined constant coefficients;
• a formation code segment for forming two two-dimensional vectors from the linear combinations;
• a generation code segment for generating Euclidian norms or approximation of Euclidian norms, from the vectors;
• and
• a generation code segment for generating singular values as linear combinations of the norms;
• if mipmapping is configured:
• if anisotropic filtering is not configured:
• a generation code segment for generating an isotropic level of detail (LOD) from a selected singular value from the generated singular values;
• a selection code segment for selecting a texture map based upon the LOD;
• an update code segment for updating the current texture map position;
• if anisotropic filtering is configured:
• a generation code segment for generating an anisotropic level of detail (LOD) from a selected singular value from the generated singular values;
• a selection code segment for selecting a texture map based upon the LOD;
• an update code segment for updating the current texture map position;
• if anisotropic filtering is configured:
• a generation code segment for generating an anisotropic ratio and an anisotropic line from singular value decomposition comprising:
• a determination code segment for determining the reciprocal of the Euclidian norms;
• a creation code segment for creating linear combinations of the reciprocals of the linear combinations and generating two two-dimensional vectors from the linear combinations;
• and
• a generation code segment for generating the Euclidean norm of the vectors;
• an adder code segment for adding at least one anisotropic offset to update the current texture map position;
• and
• a selection code segment for selecting at least one texture mapping data based upon the current texture map position.