Hewlett-packard Company

Bradley L Saunders

Roland M Hochmuth

Ross Cunniff

Samuel C Sands

Brett Edward Johnson

Alan D Ward

A method of buffering graphics vertex commands adaptively. A minimally-formatted vertex values buffer is created. As vertex commands are received from application software, attribute values are stored in an attribute values buffer until a vertex coordinate command is received. Upon receipt of a vertex coordinate command, attribute values are copied from the attribute values buffer into the vertex values buffer. Whenever application software issues a vertex attribute command corresponding to an attribute type that is not currently reflected in the vertex values buffer format, the vertex values buffer is automatically reformatted to include the new attribute type. Thus, the vertex values buffer automatically adapts itself to the behavior of the application. Multiple primitives are buffered between flushes. First-call and subsequent-call versions of code are provided for vertex commands. At initialization, a dispatch table is populated with pointers to the first-call versions. Thereafter, the dispatch table entries are manipulated by the commands themselves. Multiple subsequent-calls versions are provided for a single vertex coordinate command, each of the different subsequent-calls versions optimized for a different vertex values buffer format. The first-call version of the command determines which of the subsequent-calls versions is optimal for the current vertex values buffer format, and places a pointer to the optimized version in the dispatch table. Thereafter, the copying of values from the attribute values buffer into the vertex values buffer is done by the subsequent-calls version in a manner that corresponds exactly to the current vertex values buffer format, and without making any decisions.

Adaptive buffering of computer graphics vertex commands

A computer graphics system includes a host computer, including a graphics application program and an application programming interface, and graphics hardware. The application programming interface creates a display list for receiving and storing user-specified commands and stores each user-specified texture download command in a texture image list. When a texture processing command is received and the corresponding texture map is optimizable, the texture image list is stored in a texture object, the texture object is marked as not downloaded and a bind texture call is inserted in the display list. The bind texture call contains a reference to the texture object. When the display list is executed, each bind texture call in the display list is processed by: (a) downloading the texture map referenced by the bind texture call to the graphics hardware when the referenced texture object is marked as not downloaded, and marking the referenced texture object as downloaded, and (b) binding texture information in the texture object to a current texture state, wherein the texture map is downloaded to the graphics hardware only once for a given texture state of the application programming interface.

Graphics application programming interface avoiding repetitive transfer

The invention provides a method for the fast downloading of textures to graphics hardware for use in computer graphics. By loading the textures directly into hardware, and by making that the only copy of the texture which is downloaded, it is possible to save the time and memory space which have heretofore been required to make at least two additional copies of the texture. Instead, bookkeeping entries are made which tell the graphics API and the applications software that the texture is already available in the graphics hardware.

Method for fast downloading of textures to accelerated graphics hardware

The invention provides a method for downloading texel data into a contiguous block of memory (FIG. 3, 46) in a computer graphics system. The texel data for the first level is downloaded, and from the memory map level number and the size of the MIP map, the amount of contiguous memory needed is allocated for a contiguous block of memory for all of the MIP map levels associated with the texture (FIG. 3, 6). Then, the data for the first MIP map is placed into the contiguous memory in the appropriate location for the level number based upon a computed offset value (FIG. 3, 62). As additional MIP map levels are downloaded, if they have level numbers and sizes which are consistent with the first downloaded MIP map, an offset value is computed, based upon their level number, and they are placed into the appropriate location in the contiguous memory block. Alternatively, if a MIP map is downloaded which is not consistent with the data previously downloaded, it is placed into temporary memory, and a flag is set (FIG. 5, 31). Each time the base level data is downloaded for a particular texture, if there is a consistent set of data which was not in contiguous memory, it is placed into contiguous memory (FIG. 5, 33).

Method for maintaining contiguous texture memory for cache coherency

The invention provides a method for downloading texel data into a contiguous block of memory in a computer graphics system. The texel data for the first level is downloaded, and from the memory map level number and the size of the MIP map, the amount of contiguous memory needed is allocated for a contiguous block of memory for all of the MIP map levels associated with the texture. Then, the data for the first MIP map is placed into the contiguous memory in the appropriate location for the level number based upon a computed offset value. As additional MIP map levels are downloaded, if they have level numbers and sizes which are consistent with the first downloaded MIP map, an offset value is computed, based upon their level number, and they are placed into the appropriate location in the contiguous memory block. Alternatively, if a MIP map is downloaded which is not consistent with the data previously downloaded, it is placed into temporary memory, and a flag is set. Each time the base level data is downloaded for a particular texture, if there is a consistent set of data which was not in contiguous memory, it is placed into contiguous memory.

Growing community of inventors

Fort Collins, CO, United States of America

Bradley L Saunders