Guard region and hither plane vertex modification for graphics rendering
OwnerMei-Chi Liu, Adrian Sfarti +3inventors
InventorsMei-Chi Liu, Adrian Sfarti, Adam Malamy, Nicholas Baker, John Cumming
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Abstract
Performing graphics rendering without the computational expense of hither plane clipping and with only a minimum of display image clipping. Where a three dimensional polygon crosses to both sides of a hither plane, any vertices on the back side of the hither plane are translated to the hither plane, producing polygons which occupy only the area in front of the hither plane. A display image memory, from which display images are generated, is located within a larger guard memory such that many images which would need to be clipped to fit in the display image memory may be written to the guard memory without clipping.
Claims14
In a three-dimensional rendering system, a method of rendering a polygon with reference to a hither plane that eliminates dipping when the polygon crosses through the hither plane, which hither plane separates a side of a scene that is to be rendered from a side of the scene that is not to be rendered, the method comprising the steps of:
- for each vertex of the polygon,
- determining whether the vertex is on the side of the hither plane that is not to be rendered;
- and
- responsive to a determination that the vertex is on the side of the hither plane that is not to be rendered, changing the location of the vertex to a location on the side of the hither plane that is to be rendered, the location being independent of all other vertices of the polygon.
A method of using a hither plane to render a three dimensional polygon to screen memory that eliminates hither plane clipping when the polygon crosses through the hither plane, which polygon is indicated within a three dimensional scene, which screen memory is a subset of a larger total memory, which total memory corresponds to a portion of an image plane, and which hither plane separates a side of the scene that is to be rendered from a side of the scene that is not to be rendered, the method comprising the steps of.
- for each vertex of the polygon:
- determining whether the vertex is on the side of the hither plane that is not to be rendered;
- and
- responsive to a determination that the vertex is on the side of the hither plane that is not to be rendered, changing the location of the vertex to a location on the side of the hither plane that is to be rendered, the location being of all other vertices of the polygon;
- determining a two dimensional projection of the polygon to the image plane;
- responsive to the projection being entirely within the portion of the image plane which corresponds to the total memory, rendering the projection to the total memory;
- and
- responsive to the projection being partially within the portion of the image plane which corresponds to the screen memory and being partially outside the portion of the image plane which corresponds to the total memory;
- clipping the projection to produce a clipped projection which lies entirely within the portion of the image plane which corresponds to the total memory;
- and
- rendering the clipped projection to the total memory.
A computer program product for implementing a method of using a hither plane to render a three dimensional polygon to screen memory that eliminates hither plane clipping when the polygon crosses through the hither plane, which polygon is indicated within a three dimensional scene, which screen memory is a subset of a larger total memory, which total memory corresponds to a portion of an image plane, and which hither plane separates a side of the scene that is to be rendered from a side of the scene that is not to be rendered, the computer program product comprising a computer-readable medium containing program code means for implementing a method comprising the steps of:
- for each vertex of the polygon:
- determining whether the vertex is on the side of the hither plane that is not to be rendered;
- and
- responsive to a determination that the vertex is on the side of the hither plane that is not to be rendered, changing the location of the vertex to a location on the side of the hither plane that is to be rendered, the location being independent of all other vertices of the polygon;
- determining a two dimensional projection of the polygon to the image plane;
- responsive to the projection being entirely within the portion of the image plane which corresponds to the total memory, rendering the projection to the total memory;
- and
- responsive to the projection being partially within the portion of the image plane which corresponds to the screen memory and being partially outside the portion
- of the image plane which corresponds to the total memory:
- clipping the projection to produce a clipped projection which lies entirely within the portion of the image plane which corresponds to the total memory, and
- rendering the clipped projection to the total memory.
Dependencies are inferred from the claim text.