Abstract
A procedure for creating smooth and continuous moving displays on a microcomputer using the TMS 9918A video display processor (VDP) is discussed. This processor shares all of the features of other VDPs and, in addition, enables the user to directly program smooth motion of specified graphics shapes (sprites) with multilevel pattern overlaying. The general principles for programming this video chip are described, and a machine language driver is presented. Three illustrative applications from the event perception literature—wheel-generated motion, kinetic disruption of optical texture, and biomechanical motions—are presented as demonstrations of how the unique features of this video chip can be implemented in the creation of dynamic displays.
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Preparation of this paper was supported in part by NICHD Grant HD-16195. We wish to thank Dennis Proffitt for his assistance in the creation of some of the figures and Marshall M. Haith for his comments on a previous version of this manuscript.
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Bertenthal, B.I., Kramer, S.J. The TMS 9918A VDP: A new device for generating moving displays on a microcomputer. Behavior Research Methods, Instruments, & Computers 16, 388–394 (1984). https://doi.org/10.3758/BF03202464
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DOI: https://doi.org/10.3758/BF03202464