| |
Bastet
Registered: Jul 2005
Posts: 88 |
Sprite multiplexing, when is it save to edit the values?
I have a little question to the pros here, when is it save to edit the sprite data so that the first one dosnt get corrupted?
Do i have to wait the full 21 lines of the sprite or can i savely edit it somewhere in betwhen there? |
|
... 15 posts hidden. Click here to view all posts....
|
| |
Oswald
Registered: Apr 2002
Posts: 5094 |
so simple that I have invented it by my own in around 92 after roughly 1.5 years of asm coding at the age of 16. |
| |
Radiant
Registered: Sep 2004
Posts: 639 |
*hands Oswald a medal* |
| |
JackAsser
Registered: Jun 2002
Posts: 2014 |
Most often I still stick to using intermediate sprite images since switching $d018 to change all pointers are so limiting when it comes to different Y-positions of the sprites etc + intermediate sprite images allows a slack of 10-11 raster lines, where as a $d018 change still needs quite tight timing.
For instance if you have NMI timers and shit going on at the same time that collides with the raster IRQ u're fucked with the $d018 approach anyways.
|
| |
Oswald
Registered: Apr 2002
Posts: 5094 |
radiantx :D |
| |
Cruzer
Registered: Dec 2001
Posts: 1048 |
Quote: If you are only interested in changing the shape (framepointer) you can use a trick Usagi Yojimbo & Double Dragon 3 (possibly others) use: have a half-shape that has the new upper part but old lower part. Then changing the framepointer isn't timecritical anymore, but there's added memory use and added trouble of changing to the real new shape after the new sprite has started displaying.
Actually this doesn't have to take that much more memory, at least not double up. E.g. if you just need a flexibility of say 3 lines to change the sprite pointer, you only need to waste about 3 lines of gfx for each 18 lines, i.e. use 1/6th more memory.
Here's how I would do it... The first sprite is displayed normally on line 1-18. Then you need to change the pointer on line 19, 20 or 21. For these lines the new sprite image should double the line 19+20+21 of the old one. Then the new sprite image is displayed normally for its line 1-15, and after that the pointer needs to be changed on line 16/17/18. For these lines the new sprite image again has to double the gfx, and after this the displaying continues normally for line 19,20,21, and then cycles to 1,2,3...12. And so on, until the final sprite, which needs to end with 3 empty lines, where you have time to switch to an empty sprite image. |
| |
HCL
Registered: Feb 2003
Posts: 728 |
@JackAsser: Well, we know you're not so good at timing and stuff, but for the rest of us it's quite ok to just split d018 i think ;)..
Btw. look at Grahams Interference-Circles in DEM for hardcore sprite splitting :). Re-implemented in Tsunami etc.. |
| |
JackAsser
Registered: Jun 2002
Posts: 2014 |
Quote: @JackAsser: Well, we know you're not so good at timing and stuff, but for the rest of us it's quite ok to just split d018 i think ;)..
Btw. look at Grahams Interference-Circles in DEM for hardcore sprite splitting :). Re-implemented in Tsunami etc..
@HCL: Yeah I know, I suck. |
| |
Oswald
Registered: Apr 2002
Posts: 5094 |
HCL, any trick in DEM that wasnt mentioned here ? |
| |
hollowman
Registered: Dec 2001
Posts: 474 |
Quote: So simple, yet so elegant. Thanks hollowman! :-)
And I thank Iopop. Not everyone is wonderbug like Oswald when it comes to coding |
| |
Bastet
Registered: Jul 2005
Posts: 88 |
For the curious, i want to make a playfield out of sprites.
3x3 sprites with 2 layers (one mc and one hires) and the "non shown" sprites for nice and smooth per pixel scrolling. |
| Previous - 1 | 2 | 3 - Next |
