Graphics data accumulation for improved multi-layer texture performance

A graphics system comprising:

• a texture memory configured to store a plurality of texture layers;
• a texture accumulation buffer;
• a hardware accelerator configured to receive vertices defining a triangle, perform first access operations to a first of said texture layers in the texture memory, apply first textures generated in response to said first access operations to samples residing interior to said triangle resulting in first textured samples, and store the first textured samples in the texture accumulation buffer;
• wherein the hardware accelerator is further configured to (a) perform Ith access operations to an Ith of said texture layers in the texture memory, (b) access the texture accumulation buffer for (I−1)st cumulatively textured samples, (c) apply Ith textures generated in response to said Ith access operations to the (I−1)st cumulatively textured samples to obtain Ith cumulatively textured samples, and (d) store the Ith cumulatively textured samples in said texture accumulation buffer;
• wherein the hardware accelerator is configured to repeatedly perform (a), (b), (c) and (d) for successive values of the index I, wherein the first textured samples are identical to the (I−1)st cumulatively textured samples with I equal to a first of said successive values;
• wherein the Ith cumulatively textured samples with I equal to a last of said successive values are usable to define a portion of a video output signal displayable on a display device.

A method for generating graphical images, the method comprising:

• receiving vertices defining a triangle;
• determining fragments of a rendering space which intersect the triangle;
• determining samples in said intersecting fragments which reside interior to said triangle;
• (a) accessing texels from an Ith texture layer stored in a texture memory;
• (b) applying textures derived from said texels of said Ith texture layer to the interior samples of said intersecting fragments;
• repeatedly performing (a) and (b) for successive values of the index I;
• storing updated versions of said interior samples in a texture accumulation buffer between successive iterations of (b);
• and
• filtering the samples, after a final iteration of said repeatedly performing (a) and (b), to generate pixel values, wherein said pixel values define at least a portion of a video output signal.

A method for generating graphical images, the method comprising:

• receiving vertices defining a triangle;
• determining fragments which intersect the triangle;
• (a) accessing texels from an Ith texture layer stored in a texture memory;
• (b) applying textures derived from said texels of said Ith texture layer to color values of said intersecting fragments;
• repeatedly performing (a) and (b) for successive values of the index I;
• storing updated versions of said color values of said intersecting fragments in a texture accumulation buffer between successive iterations of (b);
• assigning color values of said intersecting fragments, after a final iteration of said repeatedly performing (a) and (b), to samples in said intersecting fragments, wherein said sample reside interior to the triangle;
• and
• filtering the samples to generate pixel values, wherein said pixel values define a portion of a video output signal.