System and method for composing a display frame of multiple layered graphic sprites
First Claim
1. In a data processing apparatus having a graphics display device for displaying a display frame comprising a plurality of display frame pixels, the data processing apparatus having a display frame composition buffer with mapped locations corresponding to the individual display frame pixels, a method of displaying graphic sprites represented by sprite pixels and having specified depths relative to each other, the method comprising the following steps:
- designating at least one of the graphic sprites to be a video sprite;
setting non-transparent pixels of the designated graphic sprite to a pre-selected key value;
writing at least the non-transparent pixels of the graphic sprites to the display frame composition buffer;
beginning said writing step with the pixels of the graphic sprite having the greatest depth and proceeding with the pixels of the remaining graphic sprites in order of decreasing depth, wherein each sprite pixel written to a particular display frame composition buffer location replaces any sprite pixel previously written to that same particular display frame composition buffer location;
overlaying a video image on the display frame, said overlaying being performed only over those display frame pixels contained in the display frame composition buffer which equal the pre-selected key value, the designated graphic sprite and its video image thereby appearing layered among the other graphic sprites in accordance with the respective depths of the graphic sprites.
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Accused Products
Abstract
A data processing apparatus includes a graphics display device for displaying a display frame comprising a plurality of display frame pixels. A sprite management system composes the display frame from a plurality of graphic sprites. Each graphic sprite comprises a plurality of sprite pixels and corresponding sprite pixel values. Each sprite has a specified depth relative to the other sprites. One of the sprites is designated to be a video sprite. This sprite is loaded with a chroma-key value. The sprite management system includes a data processing device connected to access a display frame composition buffer. The data processing device is programmed to write pixel values of individual sprites to the display frame composition buffer. This writing begins with the pixel values of the sprite having the greatest depth and proceeds with the pixel values of the remaining sprites in order of decreasing sprite depth. The display frame data is then passed to a video overlay board which overlays a video image over those pixels containing the chroma-key value. The result is a display frame in which the plurality of graphic sprites, including the video sprite, appear layered with respect to each other in accordance with their respectively specified depths.
69 Citations
26 Claims
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1. In a data processing apparatus having a graphics display device for displaying a display frame comprising a plurality of display frame pixels, the data processing apparatus having a display frame composition buffer with mapped locations corresponding to the individual display frame pixels, a method of displaying graphic sprites represented by sprite pixels and having specified depths relative to each other, the method comprising the following steps:
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designating at least one of the graphic sprites to be a video sprite; setting non-transparent pixels of the designated graphic sprite to a pre-selected key value; writing at least the non-transparent pixels of the graphic sprites to the display frame composition buffer; beginning said writing step with the pixels of the graphic sprite having the greatest depth and proceeding with the pixels of the remaining graphic sprites in order of decreasing depth, wherein each sprite pixel written to a particular display frame composition buffer location replaces any sprite pixel previously written to that same particular display frame composition buffer location; overlaying a video image on the display frame, said overlaying being performed only over those display frame pixels contained in the display frame composition buffer which equal the pre-selected key value, the designated graphic sprite and its video image thereby appearing layered among the other graphic sprites in accordance with the respective depths of the graphic sprites. - View Dependent Claims (2, 3, 4, 5)
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6. In a data processing apparatus having a graphics display device for displaying a display frame comprising a plurality of display frame pixels, the data processing apparatus having a display frame composition buffer for storing a plurality of display frame pixel values at mapped locations corresponding to the individual display frame pixels, a method of displaying graphic sprites represented by sprite pixels and corresponding sprite pixel values stored in individual sprite buffers, the graphic sprites having specified depths relative to each other, the method comprising the following steps:
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designating at least one of the graphic sprites to be a video sprite; writing a pre-selected key value to at least those locations in the sprite buffer of the designated graphic sprite which correspond to non-transparent sprite pixels; identifying a sprite depth order which begins with the graphic sprite having the greatest depth and which continues with the remaining graphic sprites in order of decreasing sprite depth; transferring pixel values of individual graphic sprites from their respective sprite buffers to the display frame composition buffer; said transferring step being performed sprite by sprite in accordance with the identified sprite depth order, wherein each sprite pixel value transferred to a particular display frame composition buffer location replaces any sprite pixel value previously transferred to that same particular display frame composition buffer location; communicating the pixel values transferred to the display frame composition buffer to a video overlay circuit; the video overlay circuit performing a step of overlaying a video image on the display frame, said overlaying being performed only over those display frame pixels which have values equal to the pre-selected key value, the designated graphic sprite and its video image thereby appearing layered in accordance with the depths of the graphic sprites. - View Dependent Claims (7, 8, 9, 10, 11)
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12. In a data processing apparatus having a graphics display device for displaying a display frame comprising a plurality of display frame pixels, a sprite management system for displaying graphic sprites represented by sprite pixels, the graphic sprites having specified depths relative to each other, the sprite management system comprising:
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a data processing device; a display frame composition buffer connected to be accessed by the data processing device for storing a plurality of display frame pixels at mapped locations corresponding to the individual display frame pixels; the data processing device being programmed to designate at least one of the plurality of graphic sprites to be a video sprite and to set non-transparent pixels of the designated sprite to a pre-selected key value; the data processing device being further programmed to write at least the non-transparent pixels of the graphic sprites to the display frame composition buffer, said writing beginning with the pixels of the graphic sprite having the greatest depth and proceeding with the pixels of the remaining graphic sprites in order of decreasing sprite depth, wherein each sprite pixel written to a particular display frame composition buffer location replaces any sprite pixel previously written to that same particular display frame composition buffer location; the sprite management system further comprising a video overlay circuit connected to receive the written pixel values from the display frame composition buffer and to overlay a video image on the display frame, the video overlay circuit being of a type which overlays the video image only on display frame pixels having values from the composition buffer which are equal to the pre-selected key value, the designated graphic sprite and its video image thereby appearing layered among the other graphic sprites in accordance with the depths of the graphic sprites. - View Dependent Claims (13, 14, 15, 16)
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17. In a data processing apparatus having a graphics display device for displaying a display frame comprising a plurality of display frame pixels, a sprite management system for displaying graphic sprites represented by sprite pixels and corresponding sprite pixel values, the graphic sprites having specified depths relative to each other, the sprite management system comprising:
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a data processing device; a display frame composition buffer connected to be accessed by the data processing device for storing a plurality of display frame pixel values at mapped locations corresponding to the individual display frame pixels; individual sprite buffers corresponding to the respective graphic sprites, the sprite buffers being connected to be accessed by the data processing device, the sprite buffers containing sprite pixel values at mapped locations corresponding to the pixels of the respective graphic sprites; the data processing device being programmed to designate at least one of the plurality of graphic sprites to be a video sprite and to load the sprite buffer of the designated graphic sprite with a pre-selected key value; the data processing device being further programmed to transfer non-transparent pixel values of individual graphic sprites from their respective sprite buffers to the display frame composition buffer, said transfer beginning with the pixel values of the graphic sprite having the greatest depth and proceeding with the pixel values of the remaining graphic sprites in order of decreasing sprite depth, wherein each sprite pixel value transferred to a particular display frame composition buffer location replaces any sprite pixel value previously transferred to that same particular display frame composition buffer location; the sprite management system further comprising a video overlay circuit connected to receive the transferred pixel values from the display frame composition buffer and to overlay a video image on the display frame, the video overlay circuit being of a type which overlays the video image only on display frame pixels from the composition buffer which have values equal to the pre-selected key value, the designated graphic sprite and its video image thereby appearing layered among the other graphic sprites in accordance with the depths of the graphic sprites. - View Dependent Claims (18, 19, 20, 21)
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22. In a data processing apparatus having a graphics display device for displaying a display frame comprising a plurality of display frame pixels, a sprite management system for displaying graphic sprites represented by sprite pixels and corresponding sprite pixel values, the graphic sprites having specified depths relative to each other, the sprite management system comprising:
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a display frame composition buffer which stores a plurality of display frame pixel values at mapped locations corresponding to the individual display frame pixels; individual sprite buffers corresponding to the respective graphic sprites, the sprite buffers containing sprite pixel values at mapped locations corresponding to the pixels of the respective sprites; at least one of the plurality of graphic sprites being designated as a video sprite; loading means for loading the sprite buffer of the designated graphic sprite with a pre-selected key value; transfer means for transferring pixel values of individual graphic sprites from their respective sprite buffers to the display frame composition buffer, said transfer means first transferring the pixel values of the graphic sprite having the greatest depth and subsequently transferring the pixel values of the remaining graphic sprites in order of decreasing sprite depths, wherein each sprite pixel value transferred to a particular display frame composition buffer location replaces any sprite pixel value previously transferred to that same particular display frame composition buffer location; overlay means connected to receive the transferred pixel values from the display frame composition buffer for overlaying a video image on the display frame, the overlay means being further for overlaying the video image only on display frame pixels from the composition buffer which have values equal to the pre-selected key value, the designated graphic sprite and its video image thereby appearing layered among the other graphic sprites in accordance with the depths of the graphic sprites. - View Dependent Claims (23, 24, 25, 26)
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Specification