Abstract: A device for detecting the position of a human finger or other object on a touch-sensitive scrolling pad. Dual independent oscillators may be used to generate two pulse trains at frequencies dependent upon the capacitance of two conductors resulting from the position of the finger on the conductors. The pulses from each oscillator may be counted over a time interval. A ratio-metric measurement may be taken by calculating the ratio of the two counts, and a sum may also be calculated. The ratio of the two counts relates to finger position on the device, and their sum relates to finger pressure upon the device.

Abstract: A device for detecting the position of a human finger or other object on a touch-sensitive scrolling pad. Dual independent oscillators may be used to generate two pulse trains at frequencies dependent upon the capacitance of two conductors resulting from the position of the finger on the conductors. The pulses from each oscillator may be counted over a time interval. A ratio-metric measurement may be taken by calculating the ratio of the two counts, and a sum may also be calculated. The ratio of the two counts relates to finger position on the device, and their sum relates to finger pressure upon the device.

Abstract: A system for improved shadowing of images using a multiple pass, depth buffer approach includes rendering a scene from the perspective of a light source to construct a shadow depth map in a rasterization buffer. The system computes depth values for the two nearest geometric primitives to the light source for pixels, and stores these depth values in the rasterization buffer. Once the shadow map is constructed, it is stored in shared memory, where it can be retrieved for subsequent rendering passes. The two depth values for each element in the shadow map can be used in combination with a global bias to eliminate self-shadowing artifacts and avoid artifacts in the terminator region. The system supports linear or higher order filtering of data from the shadow depth map to produce smoother transitions from shadowed and un-shadowed portions of an image. In addition, the system supports the re-use of the shadow map and shadowed images for more than one frame.

Abstract: A layered graphics rendering pipeline measures image fidelity ("fiducials") to determine how accurately a transformed image layer approximates a rendering of a 3D object. The graphics rendering pipeline approximates the change in position or color of 3D object by transforming a rendering of the 3D object from a previous frame. The pipeline uses the fiducials to control rendering of factored scene elements to independent image layers. The pipeline then combines the layers to compute frames of animation. The types of fiducials include sampling, visibility, and photometric fiducials. The sampling fiducial measures the distortion of an image sample when warped to screen coordinates. The visibility fiducial measures the change in visibility of a scene element since a previous rendering of the scene element.

Abstract: A method for supporting image compression in a real-time graphics rendering pipeline includes sorting object geometry for a scene among image regions called chunks. The object geometry for each chunk is rendered separately, and in a serial fashion. After the object geometry is completely rendered for a given chunk, the pixel data for that chunk is compressed and stored. Each chunk of an image can be generated and stored in this manner. To assemble a display image, compressed image chunks are retrieved, decompressed, and temporarily cached. Decompressed image data in the cache is combined into a display image. The process of generating a display image with compression can be performed at real-time rates.

Abstract: A method for improved multi-pass rendering in a graphics system includes rendering geometry in a scene to generate rendered image data and then feeding back this rendered image data for a subsequent rendering pass for the same or other geometry in a scene. Geometric primitives are rasterized to generate pixel data, which is stored in a rasterization buffer. The pixel data, including lists of fragment records, is resolved and stored in a shared memory. Resolved pixel data can be combined to generate a display image at real-time, interactive rates. The resolved pixel data can also be used as a texture for subsequent rendering operations. Geometry in a scene can be rasterized in more than one pass to generate pixel data including fragments for partially covered pixels. Fragments from subsequent passes can be blended with corresponding fragments stored in the rasterization buffer from a previous pass.

Abstract: A system for improved shadowing of images using a multiple pass, depth buffer approach includes rendering a scene from the perspective of a light source to construct a shadow depth map in a rasterization buffer. The system computes depth values for the two nearest geometric primitives to the light source for pixels, and stores these depth values in the rasterization buffer. Once the shadow map is constructed, it is stored in shared memory, where it can be retrieved for subsequent rendering passes. The two depth values for each element in the shadow map can be used in combination with a global bias to eliminate self-shadowing artifacts and avoid artifacts in the terminator region. The system supports linear or higher order filtering of data from the shadow depth map to produce smoother transitions from shadowed and un-shadowed portions of an image.

Abstract: In an image processing system, a method for generating a images includes rendering graphical models comprising a scene to separate image layers called "gsprites," and then compositing these image layers to generate an image. An image processor can retrieve gsprites from memory, transform them, and composite them for display at video rates. Gsprites can be re-rendered or updated at different rates. Reducing the rendering overhead of the system, the image processor can perform an affine transformation on the gsprite to approximate motion of the graphical object that it represents, rather than re-render the object. Objects in a scene can be queued for re-rendering based on a predefined update rate, or based on the accuracy of representing the object with a transformed gsprite, rendered for a previously displayed image.

Abstract: A method for rendering graphical objects in a scene to generate a display images includes dividing the geometric primitives of models in a scene among portions or "chunks" of the view space to which the primitives will be rendered, and then rendering geometry referenced to the chunks in series in a common depth buffer. Geometry for a chunk can be rendered, including sophisticated anti-aliasing and translucency computations, using a minimum of memory. Serially rendering object geometry in chunks provides an effective form of compression because pixel fragments can be generated for one chunk at a time and then resolved. Pixel fragments can be resolved in a post-processing step for one chunk while primitives for another chunk are rasterized.

Abstract: A method for depth complexity reduction includes inserting checkpoints between depth sorted object sections in a stream of geometric primitives. In response to receiving a checkpoint while rasterizing primitives for an image region, coverage data stored for the image region is checked to determine whether each pixel in the image region is fully covered. If so, then additional primitives for the image region can be ignored to avoid rendering occluded geometry.