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Released At :
Flashback 2012
Achievements :
C64 Demo Competition at Flashback 2012 : #3
Credits :
SIDs used in this release :
Download :
Look for downloads on external sites:
Pokefinder.org
Production Info
Submitted by ready. on 11 June 2012
Some technical stuff.
The octopus automatically synchronizes its vertical jumping period to the music beat. The vertical period of the octopus has one fixed part (adjustable only with F1 and F3 keys) used for the blow phase from top to bottom and one flexible part (when octopus goes from bottom to top) which auto adapts in order to synch with the music. The synching is done using a PI controller (proportional and integral functions), just like several speed control applications in industrial engineering (speed of engines, your car uses a PI or PID controller). The nature of the problem is always to make a process follow a reference setpoint. In the demo the referance setpoint is the period in terms of screen frames taken for the music to repeat a certain pattern. The code calculates also the period in terms of screen frames that the octopus takes to go from top to bottom and back to top. The PI controller compares the two periods and does the necessary adjustments to the octopus speed. So after a transitory phase the octopus period is the same a the music pattern period.
Still this could be improved (but the tight dealine didn't allow me to do so...), using for example a finer measure for the periods, e.g. processor cylces instead of frames. I think this would have led not only to a faster synching but also to a perfect phase alignament of the to processes (music and octopus jump). In fact now, even if the 2 periods are the same, they can be out of phase sometimes: I would like to see the octopus blow exaclty when the music pattern has been detected, but I couldn't reliably control this.
If you press 16 times F3 you see that the octopus does the fast jump upward, and blows slowly downward. In this way you really get to see that the PI controller always tries to catch up with the music, regardless of the disturbances induced by the changed blowing speed. Of course there are transitories, so the octopus doesn't catch the rithm immediately.
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Production Info
Submitted by Raffox|HF on 10 June 2012
| * No Animals Were Harmed During the Making of This One-File Demo * |
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