Method of producing a sequence of triangles from a vertex raster with and without half resolution edges while decompressing a compressed geometry stream

摘要

A method of producing a sequence of triangles from a compressed geometry stream that includes an array of vertices includes steps of parsing vertices and pushing the parsed vertices into a buffer until the last vertex of the current row of the array is parsed and pushed. The first vertex of the current row is then re-used from the buffer and drawn. The first vertex of the next row is then parsed from the geometry stream, pushed into the buffer and drawn. Thereafter, it is determined whether a quad split bit is asserted. If the quad split bit is not asserted, the next vertex from the current row is parsed, pushed into the buffer, and drawn. The next vertex of the previous row is then re- used from the buffer and the re-used next vertex is drawn. If the quad split bit is asserted, the next vertex of the previous row is re-used from the buffer and drawn. The next vertex from the current row is then parsed and pushed into the buffer. Thereafter, the method returns to the determining step until the last vertex of the current row is reached, and returns to the first vertex re-using step until the last vertex of the array is reached. A triangle is formed from each three consecutive drawn vertices, to thereby create the sequence of triangles, starting from the beginning of each row. The raster may include one or more half- resolution edges, wherein alternate vertices are dropped and not drawn.