35
Interface for Geometry Accelerator (Z13, Z25, and V25)
Geometry calculations, such as lighting and perspective adjustment, are performed either by
the host processor or by an optional Geometry Accelerator. If installed, the Geometry
Accelerator sends vertex data to the Rasterization Accelerator via a dedicated connector. A
direct connection allows data to flow quickly to the Rasterization Accelerator, which enhances
performance.
Graphics Engine
The Graphics Engine is the core of the Rasterization Accelerator. It accelerates the translation
of high-level graphics requests into pixel-oriented requests through derivative calculations and
span iteration. It then coordinates the movement of pixels to the Frame Buffer.
High-Level Vertex Interface
The Rasterization Accelerator allows the software to send vertex data for triangles and vectors
in multiple formats. Supported formats include 8-bit packed integer, 16-bit packed integer,
32-bit integer, single-precision floating point, and double-precision floating point.
The host processor achieves higher performance because it does not convert data that is native
to a particular application. To conserve bandwidth, the application optionally loads constant
color and Z values to avoid sending them with each vertex.
Gouraud Shading Support
The Graphics Engine supports smooth shading of 3D triangle meshes with the Gouraud
algorithm. High performance hardware accomplishes the shading of the entire triangle,
including color and depth derivative calculations and pixel interpolation. The hardware also
allows maximum update rates with minimum load on the host processor.
Symbolized Vector Support
The Graphics Engine supports the application of any user-supplied, two-color pattern onto
vectors without performance degradation. Dotted or dashed lines are examples of symbolized
vectors.
Antialiased Vector Support
Hardware support of antialiased vectors eliminates the jagged appearance of vectors on
standard raster displays.
Summary of Contents for RealiZm Graphics V25
Page 1: ...RealiZm Graphics Hardware User s Guide February 1997 DHA017120...
Page 4: ......
Page 8: ...viii...
Page 84: ......
