4 ms·
Neat. Having more than 8 sprites on screen is not hard, it just requires some well-timed interrupts to move a sprite from above the current raster location to
by kbelder 2y ago
Neat. Having more than 8 sprites on screen is not hard, it just requires some well-timed interrupts to move a sprite from above the current raster location to below it, so that the same sprite is drawn multiple times.
But I'm not sure about the end of the demo where they are all rotating on the same line. I guess it could be done with interrupts occurring partway through the horizontal scanline, but I didn't think they could be that precise?
- o11c 2y agoYoutube comments said something about "multiple apparent sprites per actual sprite, with stretching"?
- pwrrr 2y agoYeah, you can x and/or y expand a sprite, then change it to make it look like it contains more data by cleverly drawing the sprite because 1 pixel becomes 2 pixels wide in expanded mode.
- egypturnash 2y agoNope, that’s not it. There’s a video out there already that dissects it and figures out the trick.
- peterleiser 2y agoI don't know the trick, but take a look at the "7". It looks like it's made from the vertical line in "4" and a portion of another number.
- badc0ffee 2y agoThis is true, but not relevant to the trick.
- deleted 2y ago[deleted]
- boltzmann-brain 2y agoyou can't multiplex sprites so that more than 8 appear on the same line. the secret is to pretend you have a 9th sprite by emulating it with characters that look exactly like one of the sprites would.
- egypturnash 2y agoThat stops working when you open the borders and put sprites outside the area the video chip will render characters/bitmaps.
- eru 2y agoYes, but the demo is really cheeky about that. The borders are open when you can still do the normal multiplexing, because there's lots of vertical separation between the sprites. Later, when they put the sprites together on the same line, the borders are closed.
- jchw 2y agoBut in this case, that (alone) can't be it because all 9 sprites clip (smoothly) in and out of the border. So they've really gotten cheeky with this one.
- deleted 2y ago[deleted]
- Dylan16807 2y agoI don't like how you worded this post. You know the demo's point is having all 9 go at the same time, so it's quite misleading to start off describing something that sounds like the demo's point, but is not the demo's point, and saying it's "not hard". Your second paragraph mostly corrects that false impression, but I dislike that you gave a false impression to start with.
- Underphil 2y agoThis is an extremely common type of comment on articles like this. The commenter has to ensure everyone knows their credentials before offering any sort of praise to the creator. I also despise this type of self-serving comment.
- flohofwoe 2y ago9 sprites on screen at the same time is trivial (this is known as sprite multiplexing), 9 sprites on the same raster line is the actual 'aha effect' because the C64 can only do 8 sprites per line.
- Dylan16807 2y agoI'm not sure why you replied to me? Are you nitpicking that I said "go at the same time" because I think it's clear enough in context.
- pinoy420 2y agoAll you need is a little “Just”(TM) and everything is possible. Typical HN comment minimising the immense effort required to do %thing% due to their own arrogance.
- flohofwoe 2y agoThe VIC-II reads the data for each sprite at hardwired horizontal positions outside the visible area, so this sort of 'horizontal multiplexing' shouldn't work.