Method and apparatus for accomplishing Z-buffering by prediction

Claim 1

A method including a series of steps practiced in a repeated sequence for accelerating the writing of data to a buffer memory used to store data indicating a depth of each pixel to be displayed on a display screen (a Z buffer), the series of steps of the method for storing a depth of each pixel in sequence including the steps of receiving a new Z value to be stored at a position, reading an old Z value presently stored at the position int he Z buffer; writing the same one of the old Z value or the new Z value to the position in the Z buffer as was written for an immediately preceding series of steps for storing a Z value of an immediately preceding pixel in the repeated sequence, comparing the old Z value at the position of the Z buffer wit the new Z value to be stored at the position; and rewriting the position of the Z buffer if the comparison of the old Z value read from the position of the Z buffer with the new Z value to be stored at the position demonstrates that the value written was farther from the display screen than the Z value which was not written.

Claim 2

A method including a series of steps practiced in a repeated sequence for accelerating the writing of data to a buffer memory used to store data indicating a depth of each pixel to be displayed on a display screen (a Z buffer), the series of steps of the method for storing a depth of each pixel in sequence including the steps of receiving a new Z value to be stored at a position, reading an old Z value presently stored at the position int he Z buffer; writing the same one of the old Z value or the new Z value to the position in the Z buffer as was written for an immediately preceding series of steps for storing a Z value of an immediately preceding pixel in the repeated sequence, comparing the old Z value at the position of the Z buffer wit the new Z value to be stored at the position; and rewriting the position of the Z buffer if the comparison of the old Z value read from the position of the Z buffer with the new Z value to be stored at the position demonstrates that the value written was farther from the display screen than the Z value which was not written.

Claim 4

A method for accelerating writing of data to a buffer memory where the writing to the buffer memory depends upon a comparison of old and new data at each position of the buffer memory and positions are written sequentially including the steps of reading an old value presently stored at a first position in the buffer memory, presenting a new value to be written to the first position in the buffer memory, and writing either the new value or the old value conditionally tot he first position in the buffer memory if a result of a last available comparison in a sequence of comparisons of old and new data at a position preceding the first position produced a similar result, and comparing the old value at the first position of the buffer memory with the new value to determine the correctness of the new value conditionally written.

Claim 5

A method for accelerating writing of data to a buffer memory where the writing to the buffer memory depends upon a comparison of old and new data at each position of the buffer memory and positions are written sequentially including the steps of reading an old value presently stored at a first position in the buffer memory, presenting a new value to be written to the first position in the buffer memory, and writing either the new value or the old value conditionally tot he first position in the buffer memory if a result of a last available comparison in a sequence of comparisons of old and new data at a position preceding the first position produced a similar result, and comparing the old value at the first position of the buffer memory with the new value to determine the correctness of the new value conditionally written.