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Interrogate I/O devices (eg. mouse)

Interpret I/O and set toggles and flags

Draw updated picture using toggles and flags

•The first program loop examines inputs and user requests from the mouse, keyboard, etc. Based on these values we reset internal flags and registers.

•Based on the values of the internal registers the drawing is updated.

•During execution, the program loops through both of these operations, and thus provides a separation between simultaneous control, and display motion.

•With this architecture it is easy to add ‘real time’ control functions.

12.11 REFERENCES

Chang, T-C., Wysk, R.A. and Wang, H-P., Computer-Aided Manufacturing, Second Edition, Prentice Hall, 1998.

Foley, J., Van Dam, A., “Fundamentals of Interactive Computer Graphics”, AddisonWesley, 1984.

Glassner, A.S., “An Introduction to Ray Tracing”, Academic Press, 1989.

Glassner, A.S., “Graphics Gems”, Academic Press, 1990.

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Harrington, S., “Computer Graphics: A Programming Approach”, McGraw Hill, 1983.

Rogers, D.F., Adams, J.A., “Mathematical Elements for Computer Graphics”, McGraw Hill, 1990.

12.12 PRACTICE PROBLEMS

1 Given the geometry below, draw how it would appear with 5 different computer graphics techniques.

light