Patent ID: 6897858

Claim:
A method for partially decompressing a compressed image having a plurality of compressed tiles, wherein each compressed tile corresponds to a tile, wherein each tile has a plurality of vertices, the method comprising: classifying each vertex of each tile by; determining whether each vertex is above a view frustum; determining whether each vertex is below the view frustum; determining whether each vertex is the right of the view frustum; and determining whether each vertex is to the left of the view frustum; setting a first bit of a bit code of a vertex when the vertex is to the left of the view frustum; setting a second bit of the bit code of the vertex when the vertex is to the right of the view frustum; setting a third bit of the bit code of the vertex when the vertex is below the view frustum; and setting a fourth bit of the bit code of a vertex when the vertex is above the view frustum; selecting a plurality of relevant tiles by: selecting each tile as a relevant tile when a bitwise logic AND of a bit-code of a first vertex of a tile with a bit-code of a second vertex of the tile is equal to zero, wherein said first vertex and said vertex are adjacent vertices; and selecting each tile as a relevant tile when a bitwise XOR of the bit-code the first vertex with a bit-code of a first opposite vertex is equal to 1111 b and a bitwise XOR of the bit-code of the second vertex with a bit-code of a second opposite vertex is equal to 1111 b; retrieving a compressed tile corresponding to each relevant tile thereby forming a plurality of relevant compressed tiles; and decompressing each of the relevant compressed tile.