摘要:
A system and method for performing tangent space lighting in a deferred shading graphics processor (DSGP) encompasses blocks of the DSGP that preprocess data and a Phong shader that executes only after all fragments have been preprocessed. A preprocessor block receives texture maps specified in a variety of formats and converts those texture maps to a common format for use by the Phong shader. The preprocessor blocks provide the Phong shader with interpolated surface basis vectors (vs, vt, n), a vector Tb that represents in tangen/object space the texture/bump data from the texture maps, light data, material data, eye coordinates and other information used by the Phong shader to perform the lighting and bump mapping computations. The data from the preprocessor is provided for each fragment for which lighting effects need to be computed. The Phong shader computes the color of a fragment using the information provided by the preprocessor. The Phong shader performs all lighting computations in eye space, which requires it first to transform bump data from tangent space to eye space. In one embodiment the Phong hardware does this by multiplying a matrix M whose columns comprise eye space basis vectors (bs, bt, n) derived from the surface basis vectors (vs, vt, n) and the vector Tb of bump map data. The eye space basis vectors are derived by the DSGP preprocessor so that the multiplication (M×Tb) gives the perturbed surface normal N′ in eye space, reflecting the bump effects. The perturbed surface normal N′ is subsequently used in the lighting computations.
摘要:
A deferred graphics pipeline processor comprised of a mode extraction unit and a Polygon Memory associated with the polygon unit. The mode extraction unit receives a data stream from a geometry unit and separates the data stream into vertices data, and non-vertices data which is sent to the Polygon Memory for storage. A mode injection unit receives inputs from the Polygon Memory and communicates the mode information to one or more other processing units. The mode injection unit maintains status information identifying the information that is already cached and not sending information that is already cached, thereby reducing communication bandwidth.
摘要:
Three-dimensional computer graphics systems and methods and more particularly to structure and method for a three-dimensional graphics processor and having other enhanced graphics processing features. In one embodiment the graphics processor is a Deferred Shading Graphics Processor (DSGP) comprising an AGP interface, a command fetch & decode (2000), a geometry unit (3000), a mode extraction (4000) and polygon memory (5000), a sort unit (6000) and sort memory (7000), a setup unit (8000), a cull unit (9000), a mode injection (10000), a fragment unit (11000), a texture (12000) and texture memory (13000) a phong shading (14000), a pixel unit (15000), a backend unit (1600) coupled to a frame buffer (17000). Other embodiments need not include all of these functional units, and the structures and methods of these units are applicable to other computational processes and systems as well as deferred and non-deferred shading graphical processors.
摘要:
A method for preventing deadlock due to the need for data exclusivity when performing forced atomic instructions in a multi-level cache in a multi-processor system. The system determines whether an aligned multi-byte word in which the data of a forced atomic instruction, such as an integer store operation, is exclusive in a first level cache. If so, the forced atomic instruction is allowed to enter a second level cache pipeline. If not, the forced atomic instruction is prevented from entering the second level cache pipeline and a cache miss and fill operation is initiated to cause the aligned word to be exclusive in the first level cache.