-> Get practice using the multisprite kernel
-> Observe the flicker management algorithm for virtual sprites in action.
-> Implement the playfield as a dark grey checkerboard to facilitate line counting
-> Use numbers for the sprite graphics to identify them on screen.
-> Arrange the sprites in a tight line so side by side veritcal differences are easier to measure.
-> Joy 0 moves the sprites. Up and down move virtual sprites 1 through 5 at different velocities to cause combinations of overlap.
-> Joy 0 left and right moves P0, M0, M1 and the ball vertically.
-> M0 and M1 are drawn 1 scanline lower than all the other graphics which are aligned to the 2LK kernel line. This is not unsurprising, but may need to be considered for collision detection.
-> COLUP0 must be set every frame. The kernel resets it to black during drawscreen.
-> BUG? If a sprite or the ball is visible at the bottom line pair on the screen the last row of pixels is drawn for a 3rd scanline below the last PF graphics.
-> With the screenheight set to 84:
-----> P0's lower left corner of screen is x = 0, y = 11.
-----> P1's through P5 lower left corner of screen is x = 8, y = 8.
-----> For M0, M1 the lower left corner is x = 1, y = 1, but M0 and M1 droop 1 scanline down.
-----> Ball lower left corner is x = 1, y = 2.
-> Flicker behavior is the same for pfheight values of 1, 3 and 7.
-> Setting pfheight to 0 scrambles the screen as documented in the bBasic manual, but you can see when repositionings are being done.
-> Virtual sprites require a horizontal gap of 2 lines to reposition without flicker.
-> Flickering fails for some cases when more than 2 sprites overlap.
Recommendations for improving bBasic:
-> The language is fine, but the portion of the manual for the mulity sprite kernel has some unclear language.
------> What is the default value for pfheight?
------> The screenheights of 80 and 84 only work with some pfheights all 7 or less, but pfheight can be 15 and 31. What are the legal screenheights for those values. A table of legal combinations of screenheight and pfheight would make things more clear and complete.