Pseudo random number generator and method

1. A method for generating noise for a pixel, comprising:

receiving a plurality of pixel values;

receiving pixel position information;

generating a plurality of intermediate values, with each successive intermediate value being based on a preceding intermediate value, wherein generating the plurality of intermediate values comprises fetching information from a permutation table based on the pixel position information for at least one of the intermediate values;

generating a final value representing a random number based on a subset of the plurality of intermediate values;

using the random number to index at least one of a plurality of gradient noise tables;

applying noise information from the at least one of the plurality of gradient noise tables to at least one pixel for later display; and

storing in memory one or more of: the noise information and the at least one pixel to which the noise information was applied.

2. The method of claim 1 , wherein generating a plurality of intermediate values further comprises:

logically scrambling a first portion of the pixel position information;

selecting from a plurality of values a first intermediate value indexed by the first logically scrambled data;

logically scrambling a second portion of the pixel position information;

selecting from the plurality of values a second intermediate value indexed by the second logically scrambled data;

logically scrambling the pixel position information; and

selecting from the plurality of values a third intermediate value indexed by the logically scrambled data.

3. The method of claim 2 , further comprising:

generating a fourth intermediate value from the third intermediate value; and

manipulating the third intermediate value by the fourth intermediate value.

4. The method of claim 3 , wherein the manipulation step further comprises performing a logical exclusive-OR operation between the third intermediate value and the fourth intermediate value.

5. The method of claim 1 , wherein generating the final value comprises performing a logical exclusive-OR operation between a first respective one of the plurality of intermediate values and a second respective one of the plurality of intermediate values.

6. The method of claim 2 , wherein the first logical scrambling comprises:

performing an exclusive-OR operation on a first portion of pixel position information; and

masking off the lowest order bits from the result of the exclusive-OR operation.

7. The method of claim 2 , wherein the second logical scrambling comprises:

performing an exclusive-OR operation on a second portion of the pixel position information; and

masking off the lowest order bits from the result of the exclusive-OR operation.

8. The method of claim 2 , wherein the third logical scrambling comprises:

generating a fifth value based on the first intermediate value;

generating a sixth value based on the second intermediate value;

performing an exclusive-OR operation between the fifth value and the sixth value; and

masking off the lowest order bits from the result of the exclusive-OR operation.

9. Memory containing instructions executable by one or more processing devices that cause the one or more processing devices to:

receive a plurality of pixel values;

receive pixel position information;

generate a plurality of intermediate values, with each successive intermediate value being based on a preceding intermediate value, wherein generating the plurality of intermediate values comprises fetching information from a permutation table based on the pixel position information for at least one of the intermediate values;

generate a final value representing a random number based on a subset of the plurality of intermediate values;

use the random number to index at least one of a plurality of gradient noise tables; and

apply noise information from the at least one of the plurality of gradient noise tables to at least one pixel for later display.

10. The memory of claim 9 containing executable instructions that cause the one or more processing devices to:

logically scramble a first portion of the pixel position information;

select from a plurality of values a first intermediate value indexed by the first logically scrambled data;

logically scramble a second portion of the pixel position information;

select from the plurality of values a second intermediate value indexed by the second logically scrambled data;

logically scramble the pixel position information; and

select from the plurality of values a third intermediate value indexed by the logically scrambled data.

11. An apparatus for generating noise for a pixel comprising:

a circuit operative to:

receive a plurality of values;

receive pixel position information;

generate a plurality of intermediate values, with each successive intermediate value being based on a preceding intermediate value;

wherein the plurality of intermediate values is generated by fetching information from a permutation table based on the pixel position information for at least one of the intermediate values;

generating a final value representing a random number based on a subset of the plurality of intermediate values;

using the random number to index at least one of the plurality of gradient noise tables; and

apply noise information from the at least one of the plurality of gradient noise tables to at least one pixel for later display.