Bandwidth efficient method for generating an alpha hint buffer
AssigneeMediatek Inc.
InventorsYing-Chieh Chen, I-Hsuan Lu, Shih-Chin Lin
Life of this patent
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Abstract
A graphics processing unit (GPU) renders graphical objects into a group of pixels and stores the pixels in an on-chip buffer on the same chip as the GPU. Each pixel has an alpha value that indicates transparency of the pixel. The GPU reads the alpha value of each pixel from the on-chip buffer. According to alpha values of the group of pixels, the GPU generates an alpha hint in the system memory for the group of pixels. The alpha hint represents an aggregate of the alpha values of the group of pixels. The GPU then stores the group of pixels into a frame buffer in the system memory.
Claims18
A method for generating an alpha hint in a system memory to reduce memory access, the method comprising:
- rendering, by a graphical processing unit (GPU), graphical objects into a group of pixels stored in an on-chip buffer on a same chip as the GPU;
- reading an alpha value of each pixel from the on-chip buffer, the alpha value indicating transparency of the pixel;
- generating the alpha hint in the system memory for the group of pixels according to alpha values of the group of pixels, the alpha hint representing an aggregate of the alpha values;
- and
- storing the group of pixels into a frame buffer in the system memory,
- wherein generating the alpha hint further comprises concurrently setting different bits of the alpha hint according to the alpha values of two or more pixels in the group.
A graphics device for generating an alpha hint in a system memory to reduce memory access, the graphics device comprising:
- an on-chip buffer;
- and
- rendering hardware to render graphical objects into a group of pixels and store the group of pixels in the on-chip buffer,
- wherein the rendering hardware is further operative to:
- read an alpha value of each pixel from the on-chip buffer, the alpha value indicating transparency of the pixel,
- generate the alpha hint in the system memory for the group of pixels according to alpha values of the group of pixels, the alpha hint representing an aggregate of the alpha values,
- concurrently set different bits of the alpha hint according to the alpha values of two or more pixels in the group, and
- store the group of pixels into a frame buffer in the system memory.
Dependencies are inferred from the claim text.