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US 6,191,794 B1Granted
Method and apparatus for scaling texture maps for graphical images
AssigneeNVIDIA Corporation
InventorsCurtis Priem, David Schmenk, David Kirk
Life of this patent
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Abstract
A method which derives for each triangle to be rendered the values of the texture map coordinates in world space and the screen space two dimensional coordinates across the polygon, utilizes the values to provide two bounding boxes, compares the values of sides of the bounding boxes, and uses these comparisons to select a texture map of a scale which will provide an accurate color representation of a texture value for the pixels of the polygon.
Claims15
A method for determining a scale for a texture map to be mapped to a three dimensional surface defined by one or more polygons comprising the steps of:
- determining two dimensional screen coordinates of pixels defining a first polygon in screen space from three dimensional world space coordinates of vertices of a corresponding second polygon in world space determining the smallest and the largest two dimensional screen coordinates of some portion of the first polygon to provide a first bounding box,
- determining the smallest and the largest world space texture coordinates of a portion of the second polygon to provide a second bounding box, and
- comparing the sides of the first and second bounding boxes and using the ratio thereof to determine a scale for a texture map used to accurately reproduce the texture values for at least some of the pixels of said first polygon.
Dependencies are inferred from the claim text.