Technique for eliminating stale information from a computer graphics buffer

A method of eliminating stale information from a computer graphics buffer, comprising:

• performing a block transfer operation on pixel locations of the buffer;
• wherein a source region and a destination region for the block transfer operation are the same;
• and
• wherein, for each pixel location, the block transfer operation comprises:
• reading a clear count value associated with the pixel location;
• comparing the clear count value with a current clear count;
• and
• if the clear count value does not equal the current clear count, writing a predetermined value to the pixel location.

A method of eliminating stale information from a buffer of a computer graphics system, comprising:

• using a fast clear mode, rendering in a region of interest within the buffer;
• determining, responsive to a state of the computer graphics system, that the fast clear mode should be discontinued;
• and
• for each pixel location in the region of interest:
• reading a clear count value associated with the pixel location;
• comparing the clear count value with a current clear count;
• and
• if the clear count value does not equal the current clear count, writing a predetermined value to the pixel location.

Computer program code embodied in a machine-readable storage or transmission medium which, when executed on a computer, causes the computer to perform a method of eliminating stale information from a computer graphics buffer, comprising:

• reading a clear count value associated with a pixel location in the buffer;
• comparing the clear count value with a current clear count;
• and
• if the clear count value does not equal the current clear count, writing a predetermined value to the pixel location in the buffer.

Computer program code embodied in a machine-readable storage or transmission medium which, when executed on a computer, causes the computer to perform a method of eliminating stale information from a computer graphics buffer, comprising:

• performing a block transfer operation on pixel locations of the buffer;
• wherein a source region and a destination region for the block transfer operation are the same;
• and
• wherein, for each pixel location, the block transfer operation comprises:
• reading a clear count value associated with the pixel location;
• comparing the clear count value with a current clear count;
• and
• if the clear count value does not equal the current clear count, writing a predetermined value to the pixel location.

Computer program code embodied in a machine-readable storage or transmission medium which, when executed on a computer, causes the computer to perform a method of eliminating stale information from a buffer of a computer graphics system, comprising:

• using a fast clear mode, rendering an image in a region of interest within the buffer;
• determining, responsive to a state of the computer graphics system, that the fast clear mode should be discontinued;
• and
• for each pixel location in the region of interest:
• reading a clear count value associated with the pixel location;
• comparing the clear count value with a current clear count;
• and
• if the clear count value does not equal the current clear count, writing a predetermined value to the pixel location.