Notes for Class No. 14

Revisiting Conditional Structures and Their Use in Assignment No. 5

Tuesday, March 8, 2016

A video of this class is (or will be) posted at: http://echo360.uml.edu/heines2016/comp-mued2120.html

Handouts and Materials

Assignment No. 5

Scales and Intervals

C Major Scale
- https://www.noteflight.com/scores/view/db433343291498377d1f83399f044465d2930015
A Natural Minor Scale
- https://www.noteflight.com/scores/view/38cc0dfb9a939ff3abdef9c2accca4737564f13c
Chromatic Scale
- https://www.noteflight.com/scores/view/6abab2098657fcb9433dc3834bd40f5d8c21d32c
2nds & 5ths
- https://www.noteflight.com/scores/view/c60973c6c8c1c968de21e25258ca54c6f23162a3

Openings / Announcements / Reminders

For your reading pleasure: Emily Howell by David Cope

Class Notes

Putting It All Together (continued)

Review from last class ...

All of the following code is available at http://scratch.mit.edu/projects/19070222/#editor

Sprite Control

the hide block hides the costume for this sprite

Sprite Init (Initialize)

here we are assigning values to four variables that were created in the Data section

note that the numbers assigned are differences in MIDI note values from the starting note to the interval note

Sprite Maj. 2nd (generic Major 2nd interval)

the top stack is the one that plays a major 2nd interval

the bottom two stacks are only for testing and debugging

look carefully at the set Ending Note to Starting Note - 12 - Delta 2nd block

it is difficult to see in the screen capture, but the Starting Note - 12 - Delta 2nd part is really ( Starting Note - ( 12 - Delta 2nd ) )

this means that ( 12 - Delta 2nd ) is computed first, and then that result is subtracted from the value of Starting Note

thus, if Starting Note is 60 and Delta 2nd is 2, we get ( 60 - ( 12 - 2 ) ) = ( 60 - 10 ) = 50

this makes sense because ( Starting Note + Delta 2nd ) = ( 60 + 2 ) = 62

now you can see that the difference between 50 and 62 is 12, which is an octave, as it should be

Sprite Per. 4th (generic Perfect 4th interval)

note the similarity of the stack that plays a perfect 4th to the previous one that plays a major 2nd

Sprite Per. 5th (generic Perfect 5th interval)

again note the structural similarity of the top stack to the previous ones

the other stacks are, once again, only for testing and debugging

Sprite Min. 7th (generic Minor 7th interval)

New material begins here ...

Sprite Ver. 1, which puts these all together to play a melody

Version 2 — Selecting a Direction and an Interval at Random

http://scratch.mit.edu/projects/19070843/#editor

Version 3 — Correcting Note Doubling and Adding Musicality

http://scratch.mit.edu/projects/19070399/#editor

The next version is the same as the previous one with the addition of the Play Starting Note variable

before entering the loop, set Play Starting Note to True so that the first execution of an interval script plays the starting note
at the end of the loop, set Play Starting Note to False so that subsequent executions of interval scripts do *not* play the starting note