39 results about "Occlusion culling" patented technology

Techniques, systems, arrangements, and computer program products are operable in computer graphics systems to make shadow volumes more general with respect to the meshes that can serve as occluding geometry in such computer graphics systems, as well as for accelerating shadow volume techniques, particularly for large and complex input scenes.

A method of occlusion culling of graphic objects, comprising the steps of storing a first mask and one or more depth values associated with areas inside and outside the mask for a pre-defined region, and evaluating the visibility of the primitive covering the same region, wherein visibility evaluation begins after the computation of the coverage mask of the primitive in the region, and the computation of one or more depth values representing the pixels of the primitive. The method of the present invention is a real-time method of generating per-region coverage mask and associated Z values after the second primitive is rendered in the same region, which can maximize the bandwidth savings for Z read for both overlapping and non-overlapping primitives, with different relations between their depth values.

A method and apparatus for early occlusion culling are provided. For the method of the present invention, a host processor establishes a coarse Z-buffer. The coarse Z-buffer is divided into a series of tiles. Each tile has an associated depth value. The depth values are updated using information fed back from the Z-buffer. The host processor uses the depth values to selectively discard occluded objects before they are rendered.

The invention discloses an occlusion culling and acceleration method for drawing an outdoor ground surface in real time based on a depth map. The method comprises the following steps: drawing a current scene and storing the depth value of the scene to a piece of depth map through an acceleration algorithm; and carrying out rasterization on a bounding box of a model to be detected and judging the value of pixels in the bounding box of the model to be detected and the magnitude of the depth value in the previous step, and thus the result of occlusion culling is obtained. A portion sight line occlusion body is arranged in a scene editor in an engine, then, all objects in the scene are drawn; the least depth value of the sight line occlusion body in the current scene is recorded; and the depth value of the bounding box of the object to be detected is compared with the least depth value obtained by scene drawing, and visibility of the object is obtained. The purposes of good occlusion effect and real-time drawing can be realized.

A plurality of rows of tiles is defined in a graphics display field comprising a plurality of rows of pixels, each tile including pixels from at least two rows of pixels. Occlusion flags for respective tiles of a row of tiles for a graphics primitive are set based on whether respective representative depth values for the tiles of the row of tiles meet an occlusion criterion. Pixels in rows of pixels corresponding to the row of tiles are processed for the graphics primitive in a row-by-row manner responsive to the occlusion flags. The processing may include processing rows of pixels in the row of tiles using a zig-zag traversal algorithm.

A plurality of rows of tiles is defined in a graphics display field comprising a plurality of rows of pixels, each tile including pixels from at least two rows of pixels. Occlusion flags for respective tiles of a row of tiles for a graphics primitive are set based on whether respective representative depth values for the tiles of the row of tiles meet an occlusion criterion. Pixels in rows of pixels corresponding to the row of tiles are processed for the graphics primitive in a row-by-row manner responsive to the occlusion flags. The processing may include processing rows of pixels in the row of tiles using a zig-zag traversal algorithm.

A rendering processing apparatus is provided which performs occlusion culling for excluding from rendering targets a hidden object behind another object as seen from a point of view, when given a plurality of objects. An object input unit stores a plurality of objects in an object storing unit. An internal volume generating unit generates an internal volume which is included in a target object. A reduced Z-buffer updating unit updates a reduced Z-buffer based on the internal volume. An external volume generating unit generates an external volume which includes the target object subject to culling test. A culling determination unit consults the reduced Z-buffer and performs a Z culling test on the target object based on the external volume.

A method for accelerating occlusion culling in a graphics computer is disclosed. A depth test is performed on a fragment for a first time to determine if the fragment is visible. The fragment can be marked as potentially visible if the depth test concluded that the fragment is visible. Subsequently, the depth test is performed on the fragment for a second time to determine if the fragment is visible. If the depth test concludes that the fragment is visible, graphics processing for the fragment can be stopped at this point.

A rendering processing apparatus is provided which performs occlusion culling for excluding from rendering targets a hidden object behind another object as seen from a point of view, when given a plurality of objects. An object input unit stores a plurality of objects in an object storing unit. An internal volume generating unit generates an internal volume which is included in a target object. A reduced Z-buffer updating unit updates a reduced Z-buffer based on the internal volume. An external volume generating unit generates an external volume which includes the target object subject to culling test. A culling determination unit consults the reduced Z-buffer and performs a Z culling test on the target object based on the external volume.

Embodiments of the invention disclose an occlusion culling method for virtual role and a server, which are used to prevent the client's perspective type plug-in and to avoid the round-off error generated in the rasterization process. In the method, the server projects an obstacle onto the projection plane of a second virtual character to obtain a convex polygon of the obstacle on the projection plane, and the obstacle is located between a first virtual character and the second virtual character. The server performs rasterization on the convex polygon. The server determines whether the convex polygon completely covers the projected area occupied by the second virtual character on the projection plane based on the result of the rasterization processing. If the convex polygon completely covers the projected area of the second virtual character, the server removes the second virtual character from the field of view of the first virtual character and sends the first occlusion culling result to the client. If the convex polygon does not completely cover the projected area of the second virtual character, the server sends the second occlusion culling result to the client.

A method for performing occlusion queries is disclosed. The method includes steps of: (a) a graphics processing unit (GPU) using a first depth buffer of a first frame to thereby predict a second depth buffer of a second frame; and (b) the GPU performing occlusion queries for the second frame by using the predicted second depth buffer, wherein the first frame is a frame predating the second frame. In accordance with the present invention, a configuration for classifying the objects into the occluders and the occludees is not required and the occlusion queries for the predicted second frame are acquired in advance at the last of the first frame or the first of the second frame.

A plurality of rows of tiles is defined in a graphics display field comprising a plurality of rows of pixels, each tile including pixels from at least two rows of pixels. Occlusion flags for respective tiles of a row of tiles for a graphics primitive are set based on whether respective representative depth values for the tiles of the row of tiles meet an occlusion criterion. Pixels in rows of pixels corresponding to the row of tiles are processed for the graphics primitive in a row-by-row manner responsive to the occlusion flags. The processing may include processing rows of pixels in the row of tiles using a zig-zag traversal algorithm.

A method and image processing apparatus for creating simplified representations of an existing virtual 3D model for use in occlusion culling. The existing virtual 3D model is received and a visual hull construction is performed on the existing virtual 3D model using an approximate voxel volume consisting of a plurality of voxels, the voxel volume fully encloses the existing virtual 3D model, and a set of projections from a plurality of viewing angles to provide a visual hull of the existing 3D model. The volumetric size of the visual hull of the existing 3D model is increased to envelop the existing virtual 3D model to provide the visual hull as an occludee model, and the volumetric size of the visual hull of the existing 3D model is decreased to be enveloped by the existing virtual 3D model to provide the visual hull as an occluder model. The occludee model and the occluder model are used during runtime in a 3D virtual environment for occlusion culling.The present invention provides simplified representations for occlusion culling in a simple and computationally cost effective manner.

The invention describes a method and system for use in occlusion culling of polygons in an interactive environment, such as a game. The invention employs a boundary box to simplify the testing of occludee polygons. Occluders and occludees are also transformed into non-interpenetrating, non-overlapping polygons. Winged-edges are employed to minimize a per occludee computational cost due to precision problems that may arise at non-overlapping edges. The invention then proceeds through an active edge list to identify edge discontinuities (e.g., where an edge is added or removed from the active edge list). Depth analysis is employed to determine whether an occluder occludes an occludee at the edge discontinuity. Moreover, the invention only performs depth analysis for those locations of a screen display where an occludee is determined to reside, thereby minimizing unnecessary computations.

Z-buffer rendering of three-dimensional scenes is made more efficient through a method for occlusion culling by which occluded geometry is removed prior to rasterization. The method uses hierarchical z-buffering to reduce the quantity of image and depth information that needs to be accessed. A separate culling stage in the graphics pipeline culls occluded geometry and passes visible geometry on to a rendering stage. The culling stage maintains its own z-pyramid in which z-values are stored at low precision (e.g., in 8 bits). The efficiency of hierarchical z-buffering is improved through hierarchical evaluation of line and plane equations.

An apparatus and a method for generating 3-dimensional computer graphic images. The image is first sub-divided into a plurality of rectangular areas. A display list memory is loaded with object data for each rectangular area. The image and shading data for each picture element of each rectangular area are derived from the object data in the image synthesis processor and a texturizing and shading processor. A depth range generator derives a depth range for each rectangular area from the object data as the imaging and shading data is derived. This is compared with the depth of each new object to be provided to the image synthesis processor and the object may be prevented from being provided to the image synthesis processor independence on the result of the comparison.

An apparatus, method, and machine-readable medium for performing masked occlusion culling. For example, one embodiment of an apparatus comprises: incremental scene rendering circuitry / logic to incrementally render a first portion of a scene in a first buffer and a second portion of a scene in a second buffer; buffer merging circuitry / logic to merge the first portion of the scene and the second portion of the scene to generate merged scene data; and masked occlusion culling (MOC) circuitry / logic, responsive to a mask value in an occlusion query (OQ) mask buffer, to perform depth testing and occlusion culling operations on the merged scene data.

The invention discloses a virtual reality image processing apparatus and method. The method comprises the following steps of A, determining a sight point position and a sight line direction; B, according to the sight point position, the sight line direction and a view frustum culling algorithm, determining a scene model in a corresponding view frustum region in a preset global scene model; C, searching for a visible scene model in the scene model in the view frustum region by adopting an occlusion culling algorithm to serve as a target scene model; and D, performing fine granularity renderingprocessing on a virtual display image displayed in the target scene model. According to the apparatus and the method, the visible scene model is searched for in the scene model in the view frustum region by adopting the occlusion culling algorithm to serve as the target scene model; the scene model outside a view frustum and the invisible scene model in the view frustum can be culled; and the visible scene model in the view frustum region is rendered to generate a virtual scene image, so that the processing efficiency of an image processor is improved.

A method for accelerating occlusion culling in a graphics computer is disclosed. A depth test is performed on a fragment for a first time to determine if the fragment is visible. The fragment can be marked as potentially visible if the depth test concluded that the fragment is visible. Subsequently, the depth test is performed on the fragment for a second time to determine if the fragment is visible. If the depth test concludes that the fragment is visible, graphics processing for the fragment can be stopped at this point.

An apparatus and a method for generating 3-dimensional computer graphic images. The image is first sub-divided into a plurality of rectangular areas. A display list memory is loaded with object data for each rectangular area. The image and shading data for each picture element of each rectangular area are derived from the object data in the image synthesis processor and a texturizing and shading processor. A depth range generator derives a depth range for each rectangular area from the object data as the imaging and shading data is derived. This is compared with the depth of each new object to be provided to the image synthesis processor and the object may be prevented from being provided to the image synthesis processor independence on the result of the comparison.

The invention describes a method and system for use in occlusion culling of polygons in an interactive environment, such as a game. The invention employs a boundary box to simplify the testing of occludee polygons. Occluders and occludees are also transformed into non-interpenetrating, non-overlapping polygons. Winged-edges are employed to minimize a per occludee computational cost due to precision problems that may arise at non-overlapping edges. The invention then proceeds through an active edge list to identify edge discontinuities (e.g., where an edge is added or removed from the active edge list). Depth analysis is employed to determine whether an occluder occludes an occludee at the edge discontinuity. Moreover, the invention only performs depth analysis for those locations of a screen display where an occludee is determined to reside, thereby minimizing unnecessary computations.

The invention provides an OpenGL-based focus area visualization method and system. The method comprises the steps of S1 receiving the model data of a focus area, and constructing an n-element space subdivision tree; S2 traversing the n-element space subdivision tree, and marking tree nodes and leaf nodes in a view cone as potential visibility; S3 judging the shielded tree nodes, and marking the shielded tree nodes as invisible; and S4 calculating adaptive occlusion coefficients of the tree nodes, marking the tree nodes of which the adaptive occlusion coefficients are smaller than a preset threshold value as invisible, and rendering and displaying the remaining tree nodes. According to the invention, aiming at a large-scale complex model in an orthopaedic minimally invasive surgery, the model rendering efficiency is optimized through methods such as occlusion elimination and the like; hardware support such as texture mapping or special occlusion search is not needed; rendering of a focus area model can be completed in real time in the surgery; and conditions around a focus of a patient can be displayed in real time.

A virtual reality (VR) system that includes a three-dimensional (3D) point cloud having a plurality of points, a VR viewer having a current position, a graphics processing unit (GPU), and a central processing unit (CPU). The CPU determines a field-of-view (FOV) based at least in part on the current position of the VR viewer, selects, using occlusion culling, a subset of the points based at least in part on the FOV, and provides them to the GPU. The GPU receives the subset of the plurality of points from the CPU and renders an image for display on the VR viewer based at least in part on the received subset of the plurality of points. The selecting a subset of the plurality of points is at a first frame per second (FPS) rate and the rendering is at a second FPS rate that is faster than the first FPS rate.