Compaq Computer Corporation, Inc.

John J Watters

Giang H Dao

Randolph W Spurlock

Brian H Danielson

Timothy J McDonald

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine calculates the length of the slices responsive to line definition parameters, such as the coordinates of the two line endpoints. Groups of like-sized slices can be determined to decrease the computations necessary to compute the size of each slice. The slices can be either drawn to the display through the frame buffer or used as endpoints for other lines to be generated. To increase the speed of operation, while parameters requiring a division are being calculated, the partial quotient is being used to generate partial slices. Clipped lines can be generated in part using normal Bresenham techniques for partial slices and using the run slice techniques for the full slices entirely within a window. The run slice line draw engine can be used for a plurality of functions other than simple line draws, such as polygon fills, stretching, shrinking or shading.

Method and apparatus to draw line slices during calculation

A graphics controller for use in a computer system stores information from the screen memory portion of its frame buffer in a compressed form, either in a separate compressed data memory or a portion of the frame memory separate from the screen memory. Data in the compressed data memory references color data in a color dictionary. The display controller uses the color data from the compressed data memory to drive the display, thereby reducing accesses to the frame buffer by the display controller. Accordingly, other devices, such as hardware accelerators, have greater opportunities to access the frame buffer.

Method and apparatus for displaying computer graphics data stored in a

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine can perform non-linear scaling and shading of lines in accordance with a parametric equation by approximating the parametric equation as a polyline with a plurality of linear segments. The polyline approximation can be generated using information concerning each derivative of the parametric equation. Each linear segment of the polyline includes a plurality of slices generated by the run slice line draw engine. By approximating the polyline as a plurality of linear segments, non-linear scaling and/or shading by the run slice line draw engine can be performed without complex mathematical computations.

Run slice line draw engine with non-linear scaling capabilities

Run slice line draw engine with enhanced processing capabilites

Run slice line draw engine with stretching capabilities

Run slice line draw engine with shading capabilities

Run slice line draw engine with non-linear shading capabilities

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine calculates the length of the slices responsive to line definition parameters, such as the coordinates of the two line endpoints. Groups of like-sized slices can be determined to decrease the computations necessary to compute the size of each slice. The slices can be either drawn to the display through the frame buffer or used as endpoints for other lines to be generated. To increase the speed of operation, while parameters requiring a division are being calculated, the partial quotient is being used to generate partial slices. Clipped lines can be generated in part using normal Bresenham techniques for partial slices and using the run slice techniques for the full slices entirely within a window. The run slice line draw engine can be used for a plurality of functions other than simple line draws, such as polygon fills, stretching, shrinking or shading. Non-linear scaling and nonlinear shading can be performed in accordance with a parametric equation by approximating the parametric equation as a polyline having a plurality of linear segments. Scaling and/or shading can be performed responsive to the linear segments of the polyline, thereby avoiding complex mathematical computation. A polyline approximating a parametric equation of degree n may also be displayed on a video display using information generated for n-1 derivatives of the parametric equation.

Growing community of inventors

Spring, TX, United States of America

John J Watters