Method and apparatus for selecting a mip map level based on a min-axis value for texture mapping

An apparatus comprising:

• one or more processors coupled to memory storing executable instructions, wherein execution of the executable instructions by the one or more processors causes the one or more processors to:
• select, for a texture fetch, a mip map level from a plurality of mip map levels where the selected mip map level is based on a min-axis value without using a max-axis value and without using an amount of anisotropy wherein the min-axis value is based on a plurality of texture space derivatives with respect to screen space;
• and
• fetch texture data from memory in response to the selected mip map level based on the min-axis value.

A device comprising:

• a display;
• mip map level determination logic operative to select, for a texture fetch, a mip map level from a plurality of mip map levels based on a min-axis value that is based on a plurality of texture space derivatives with respect to screen space without using a max-axis value and without using an amount of anisotropy;
• texture addressing logic operative to fetch texture data from memory in response to the selected mip map level that is based on the min-axis value;
• and
• logic operative to determine whether a pixel is in shadow based on the fetched texture data and to provide the pixel for display at the display.

A method comprising:

• selecting, for a texture fetch, a mip map level from a plurality of mip map levels based on a min-axis value that is based on a plurality of texture space derivatives with respect to screen space without using a max-axis value and without using an amount of anisotropy;
• fetching texture data from memory in response to the selected mip map level based on the min-axis value;
• determining whether a pixel is in shadow based on the fetched texture data;
• and
• providing the pixel for display.

An apparatus comprising:

• mip map level determination logic comprising:
• length calculation logic operative to calculate a first mip map level based on a min-axis value without using a max axis value and without using an amount of anisotropy, and further operative to determine a second mip map level based on the max-axis value, wherein both the min-axis value and the max-axis value are based on a plurality of texture space derivatives with respect to screen space;
• max/min selector logic operative to select, in response to one of min-axis enable data and max-axis enable data, one of the first mip map level and the second mip map level, wherein the max/min control logic comprises:
• comparator logic operative to generate information identifying one of the first mip map level and the second mip map level as having a greater resolution;
• max/min control logic operative to generate max/min control data based on information identifying one of the first mip map level and the second mip map level as having the greater resolution, and further based on one of min-axis enable data and max-axis enable data;
• and
• multiplexing logic operative to select one of the first mip map level and the second mip map level in response to the max/min control data;
• and
• max/min/anisotropic selector logic operative to select, in response to filter mode data, one of a third mip map level, and the selected one of the first mip map level and the second mip map level, wherein the third mip map level is based on at least one of the first mip map level, the second mip map level, and the amount of anisotropy.

A method comprising:

• calculating a first mip map level based on a min-axis value without using a max-axis value and without using an amount of anisotropy, and determining a second mip map level based on the max-axis value, wherein both the min-axis value and the max-axis value are based on a plurality of texture space derivatives with respect to screen space;
• selecting, in response to one of min-axis enable data and max-axis enable data, one of the first mip map level and the second mip map level by:
• generating information identifying one of the first mip map level and the second mip map level as having a greater resolution;
• generating max/min control data based on the information identifying one of the first mip map level and the second mip map level as having a greater resolution, and further based on one of the min-axis enable data and max-axis enable data;
• and
• selecting one of the first mip map level and the second mip map level in response to the max/min control data;
• and
• selecting, in response to filter mode data, one of a third mip map level and the selected one of the first mip map level and second mip map level, wherein the third mip map level is based on at least one of the first mip map level, the second mip map level, and the amount of anisotropy.

An image stored in memory generated by:

• selecting a mip map level from a plurality of mip map levels, where the selected mip map level is based on a min-axis value without using a max-axis value and without using an amount of anisotropy, wherein the min-axis value is based on a plurality of texture space derivatives with respect to screen space;
• fetching texture data in response to the selected mip map level based on the min-axis value;
• generating an image using at least a portion of the fetched texture data;
• and storing the generated image in memory.