Principles of interactive computer graphics (2nd ed.)
Principles of interactive computer graphics (2nd ed.)
Mathematical elements for computer graphics (2nd ed.)
Mathematical elements for computer graphics (2nd ed.)
Intermixing refresh and direct view storage graphics
SIGGRAPH '76 Proceedings of the 3rd annual conference on Computer graphics and interactive techniques
An improved economic design for a display processor intermixing refresh and storage graphics
ACM SIGGRAPH Computer Graphics
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This paper describes a stand alone graphics system utilizing a microprocessor based display controller with the capability of combining refresh with storage tube graphics. This combination is accomplished by utilizing the Write-Thru feature of a Tektronix 4014 display terminal. The display controller is a typical Z-80 microprocessor system interfaced to the 4014 by a standard Tektronix parallel interface. A portion of the Z-80 memory is used as the display buffer, allowing it to be divided into store and non-store (refreshed) segments. The microprocessor performs the conversion from the simple integer X, Y coordinates in the display buffer to actual Tektronix drawing commands. A second Z-80 microprocessor is used to perform graphical transformations and transfer the data from the PDP-11 host to the Z-80 display controller. The operations performed by the second microprocessor include translation, rotation and scaling. These operations are implemented by matrix multiplication of the user data by a user specified transformation matrix. The stand alone capabilities of the graphics system is made complete with interactive devices such as a tablet, analog dials, and function switches interfaced directly to the host computer.