Microsoft Technology Licensing, LLC

Silicon Graphics, Incorporated

David L Morgan, Iii

Mark S Peercy

Angus Dorbie

Christopher J Migdal

Frederic J Noraz

Amy J Migdal

A method, system, and computer program product for filtering textures applied to a surface of a computer generated object permits an application program running on a computer system to significantly increase the graphics capabilities and performance of the computer. Rendering data for a pixel of the object is received from the application program, and a first and second set of texture coordinates is generated. Next, the first and second sets of texture coordinates are used to obtain a first and second texture sample from a texture image. The first and second texture samples are then blended together to produce a texture sample having a greater degree of filtering. This produced texture sample having a higher degree of filtering is stored in a frame buffer for subsequent display. The filtering process of the present invention can be performed either by conducting multiple passes through a graphics pipeline having a single texture unit or by conducting one pass through a graphics pipeline having multiple texture units. The filtering process of the present invention can also be performed by conducting multiple passes through a graphics pipeline having multiple texture units.

Method, system, and computer program product for filtering a texture applied to a surface of a computer generated object

A system and method for multiple texture rendering on a primitive using a fine grain multi-pass at a pixel level. The present invention has hardware capable of processing one texture and either hardware, software, and/or firmware capability to hold state information associated with several textures. The hardware rapidly switches between processing different textures and allows a very fine grain multi-pass implementation of multiple texture rendering. In one embodiment, a computer graphics raster subsystem renders multiple textures on a primitive. A fine grain scan converter takes in a primitive description with multiple sets of texture coordinates defined for each vertex. Each set of texture coordinates defines an independent texture. Each texture is associated with a texture number. The fine grain scan converter produces a set of texture coordinates at a given pixel for each of the multiple textures before moving on to the next pixel. A texture address generator and texture filter use the texture numbers and the texture coordinates associated with the texture numbers to produce a filtered texture value for each of the multiple textures. A recirculating texture blender combines color and these filtered texture values to produce a final textured color value. The fine-grain multi-pass technique for rendering multiple textures on a primitive is faster than a coarse grain multi-pass technique because the geometry does not need to be sent multiple times from a geometry engine to a raster subsystem. In addition, the fine-grain multi-pass technique is cheaper and more efficient than a parallel approach because it does not require permanent multiple texture units in a hardware connected together by texture blending units.

Fine grain multi-pass for multiple texture rendering

A method, system, and computer program product are provided for multi-pass bump-mapping into an environment map. At least two passes are made through a hardware rasterizer to bump map into an environment map. In the first pass, a lighting equation is overloaded. The overloaded lighting equation represents a reflection vector of a perturbed normal at a pixel position. The reflection vector at a pixel position is then generated according to the overloaded lighting equation. In a second pass, at least one texel in an environment map is accessed based on the generated reflection vector. For example, the generated reflection vector can be used as a look-up into the environment map to access one or more texel samples. In one example implementation, a lighting equation includes a specular material vector Sm, a lighting vector L, and an ambient material vector Am. Such a lighting equation is overloaded by setting the specular material vector Sm to equal a perturbed normal vector N&prime;, setting the lighting vector L to equal a viewing vector V at the pixel position, and setting an ambient material vector Am to equal the viewing vector V. Other terms in the lighting equation include a specular exponent n two vectors scli and acli. To overload the lighting equation, the specular component n is set to equal one, the vector scli is set to equal to &lcub;2,2,2&rcub;; and the vector acli is set to equal to &lcub;&minus;1,&minus;1,&minus;1&rcub;. A single hardware rasterizer can be used. A separate reflection vector calculation is avoided. One hardware rasterizer can be used to perform processing in each pass. Two separate texture fetch units to support a reflection vector calculation are not necessarily needed.

Method, system and computer program product for multi-pass bump-mapping into an environment map

In a graphics subsystem of a computer system, a method for adjustable texture replication. The method is implemented within the graphics subsystem of the computer system. The method includes the step of configuring a plurality of raster engines into a first cluster and a second cluster. The raster engines of the first cluster and the raster engines of the second cluster are each communicatively coupled to respective texture memories. A first texture image copy is stored among the texture memories of the first cluster such that each respective texture memory stores a respective portion of the first texture image copy. A second texture image copy is stored among the texture memories of the second cluster such that each respective texture memory stores a respective portion of the second texture image copy. A parallel texture mapping process is performed on a surface using the first cluster and the second cluster. The first cluster texture maps the first texture image copy, wherein the plurality of raster engines of the first cluster share access to the each respective texture memory storing the first texture image copy. The second cluster texture maps the second texture image copy, wherein the plurality of raster engines of the second cluster share access to each respective memory storing the second image copy. The number of clusters, and the number of raster engines within the clusters, is adjustable to implement variable texture replication.

Method and system for dynamic texture replication on a distributed memory graphics architecture

The present invention provides a method and a device for generating texture coordinates for a selected pixel within a triangle for a texture wrapping operation. The selected pixel is defined within the triangle by a plurality of barycentric coordinates. The method includes receiving a set of texture coordinates for each of the vertices of the triangle and receiving a plurality of barycentric coordinates associated with the selected pixel. The method further includes determining a plurality of barycentric coefficients for the selected pixel from the texture coordinates of the vertices of the triangle. The barycentric coefficients are optimized to obtain a specified degree of precision, which is adapted to distinguish between neighboring texture coordinates. In addition, the method includes computing the texture coordinates based on the barycentric coefficients and the barycentric coordinates, wherein the texture coordinates are substantially distinct from neighboring texture coordinates.

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Mountain View, CA, United States of America

David L Morgan, Iii