Author Topic: Total noob question (Read 19611 times)

matthias1992 · « **on:** July 14, 2010, 09:39:17 am »

Yesterday was my first hands on experience with Axe, and I love it! despite the compiled files being nearly 2x larger then the source it is incredibely fast! I do have one problem however, moving sprites. I used this code

Code: [Select]

.SPRITE
DiagnosticOff
10->X->Y
[FFFFFFFFFFFFFFFF->Pic0
Lbl DR
Pt-On(X,Y,Pic0)
Return
Repeat getKey(15)
If getKey(2)
X-1->X
sub(DR)
End
If getKey(3)
X+1->X
sub(DR)
End
End

now instead of moving one pixel left or right the sprite moves 8 pixels. How can I make this one pixel? Am I doing something wrong?

And on a slightly off topic note: I was trying to read The Complete guide to effective Axe by SirCwmp but after page 3 or so there are only blank pages (except the titles of the chapaters) can someone either verify this or upload a non-corrputed version (assuming it is not meant to have those blank spaces)

edit:just another question, how do I display sprites bigger then 8x8 at once? or do I have to make, say, a 32x32 sprite from four 8x8 sprites?
Thanks in advance.

calcdude84se · « **Reply #1 on:** July 14, 2010, 10:19:40 am »

One at a time.

AFAIK, SirCmpwn never actually released it. What you're probably talking about is just a bit he wrote up so we could give feedback on formatting.
As for larger sprites, you have two options. The first one is to use the Bitmap( command, which is a bit slower (being an OS call) and somewhat inflexible. Your other option is two draw multiple sprites, though, for 32*32, that would be 16 8*8 sprites.
Now to your main question.
First of all, the subroutine DR you have should be at the end of your code, because otherwise your program will right after drawing the sprite once. Also, you need to erase the sprite at its original location when you move it because the edges get left behind. Depending on what else you're doing, you could erase the whole screen, backup the entire screen to the backbuffer, or you might have some other option that I can't think of right now.
Also, that said, are you sure it's exactly 8 pixels? That shouldn't happen. If you haven't realized yet, the direct key commands (of the form getkey(9)) are much faster than just using getkey, and it's probably just moving very quickly.
(Note that some of my criticisms of your code may not be valid, as I'm unsure if what you posted is just an example)
Good luck in Axe!

Magic Banana · « **Reply #2 on:** July 14, 2010, 10:35:02 am »

Eh, just woke up, but let's see what we got here.

Yeah, calcdude basically covers it. I'm not seeing a DispGraph, so this program doesn't seem to be doing anything. If you don't want the sprite leaving a trail, then make sure you ClrDraw after using DispGraph. Both of those should be put after you've done all the drawing on the screen, so after sub(DR) is called. Oh, it's not really needed, but when closing a program, having ClrHome right before the program ends will clean up your screen when you exit out of it. Otherwise it seems ok. You don't really need to worry about optimizing right now so you should be fine. Just don't forget to make If statements for the Y coordinate.

jsj795 · « **Reply #3 on:** July 14, 2010, 10:35:37 am »

In the subroutine DR, before Pt-On(, put ClrDraw for, well, clearing the screen, and after Pt-On(, put DispGraph so the sprites show after you've drawn them. And see if it works

Magic Banana · « **Reply #4 on:** July 14, 2010, 10:44:35 am »

Oh, one more thing, you should probably pull the sub(DR) out of the if loops and have it call the sub after all the button presses so that if there are multiple button presses (diagonal movement) it will only make the draw command once instead of multiple times, preventing any weird mishaps. Kind of like:

Code: [Select]

If getkey(1)
blah
End
If getkey(2)
blah
End
If getkey(3)
blah
End
If getkey(4)
blah
End
sub(DR)
DispGraph
ClrDraw

@jsj795
Hmm, clearing the screen right before drawing to it might not be the best thing, considering that he could draw something else to the buffer before sub(DR) is called. Usually it's best to have it right after you display the contents of the buffer to ensure that you got everything that was needed to be displayed to be uh, displayed.

matthias1992 · « **Reply #5 on:** July 14, 2010, 10:55:06 am »

Ooh Yea i made some mistakes indeed so it should be:

Code: [Select]

.SPRITE
DiagnosticOff
10->X->Y
[FFFFFFFFFFFFFFFF->Pic0
[0000000000000000->Pic1
Repeat getKey(15)
If getKey(2)
X-1->X
sub(DR)
End
If getKey(3)
X+1->X
sub(DR)
End
End
Lbl DR
Pt-On(X-(getKey(3))+(getKey(2)),Y,Pic1) .I have not included Y movement yet for simplicity's sake.
Pt-On(X,Y,Pic0)
DispGraph .no return needed

I always try to avoid ClrDraw, maybe a bad habit in Axe but a good one on BASIC. I don't know with what logic the sprites are drawn so I am not sure if the Pic1 sprite will do what I want it to do, erase the previous position of Pic0...
I have no calc at hand so i am jsut doing this from memory and the commentary you made...
it should work now...

@magic banana
in your example code you dispGraph and then Clrdraw, shouldn't it be the other way around?

jsj795 · « **Reply #6 on:** July 14, 2010, 10:56:36 am »

@magic banana oh... Thanks for the advice lol I'm so used to clearing screen before displaying :p I was also ninja'd by you before

LordConiupiter · « **Reply #7 on:** July 14, 2010, 11:30:18 am »

Quote from: matthias1992 on July 14, 2010, 10:55:06 am

@magic banana
in your example code you dispGraph and then Clrdraw, shouldn't it be the other way around?

Then you will draw a white screen all the time, and I guess that is not what you want

ClrDraw crears the buffer, and dispGraph writes the buffer to the screen, so when you want to draw something, most times you have to clear the buffer, draw everything you want on it, and then write it to the screen with the dispGraph command.

Magic Banana · « **Reply #8 on:** July 14, 2010, 12:36:33 pm »

Quote from: matthias1992 on July 14, 2010, 10:55:06 am

I always try to avoid ClrDraw, maybe a bad habit in Axe but a good one on BASIC. I don't know with what logic the sprites are drawn so I am not sure if the Pic1 sprite will do what I want it to do, erase the previous position of Pic0...
I have no calc at hand so i am jsut doing this from memory and the commentary you made...
it should work now...

@magic banana
in your example code you dispGraph and then Clrdraw, shouldn't it be the other way around?

In Axe, DispGraph will display everything that has been drawn in the buffer onto the LCD and ClrDraw will clear the buffer, but NOT the screen. Axe is a little different than BASIC, so it will take some getting used to, but (almost) everything, unless specified, is drawn to the buffer while in BASIC, everything was drawn straight to the screen (or rather automatically updated to the screen whenever anything on the buffer was changed). In Axe, the LCD will only display what's on the buffer when you tell it to, so that is why you use DispGraph after you have drawn all of your sprites onto the buffer.

LordConiupiter is right about what you said. Deleting everything you draw on the buffer before it is displayed onto the screen = blank screen.

Also, in your sub you use Pt-On(X-(getKey(3))+(getKey(2)),Y,Pic1) do display a white block to which I am assuming to clear out the old space of where your sprite was before. There is no need for this, because your program isn't updating the screen until it gets to DispGraph, and even so, using that white block would erase anything behind your first sprite if there was anything. That is what ClrDraw is for. Unlike BASIC, everything get's drawn extremely fast because it's drawn to the buffer. Once you draw everything you need to, you simply call DispGraph once and BAM - everything is displayed on the screen all at once.

Before I get carried away about the differences between BASIC and Axe syntax, let me just revise your code a bit so you can see what I mean.

Code: [Select]

.SPRITE
DiagnosticOff
10->X->Y
[FFFFFFFFFFFFFFFF->Pic0
Repeat getKey(15)
X+getkey(3)-getkey(2)->X
Y+getkey(1)-getkey(4)->Y
sub(DR
DispGraph
ClrDraw
End
ClrHome

Lbl DR
Pt-On(X,Y,Pic0

nemo · « **Reply #9 on:** July 14, 2010, 08:45:44 pm »

Code: [Select]

.SPRITE                   . header
DiagnosticOff             . turn off indicator/done
10->X->Y                  . initialize sprite position
[3C7EFFFFFFFF7E3C->Pic0   . squares are for squares. therefore, a black circle is stored to pic0.
Repeat getKey(15)         . repeat until clear is pressed
X+getkey(3)-getkey(2)->X  . movement
Y+getkey(1)-getkey(4)->Y  . code
Pt-Change(X,Y,Pic0        . draw sprite to buffer
DispGraph                 . display what's on the buffer
Pt-Change(X,Y,Pic0        . draw same sprite to buffer. since it's pt-change, the sprite is erased on the buffer, leaving no 
End                       . residue from movement.
ClrHome                   . clear the screen, move cursor to upper left corner of the screen.
ClrDraw                   . clear the buffer.

you can use a subroutine for pt-change() if those 10 bytes you save are really important to you.

shmibs · « **Reply #10 on:** July 14, 2010, 09:12:19 pm »

a subroutine is nice when you use a routine more than once in your program but otherwise they should generally be avoided as they add size and make the program more difficult to read

also, nemo's ptchange method is useful if you want a background image without having to store it in the backbuffer and do swapping(freeing up more RAM for storage)

matthias1992 · « **Reply #11 on:** July 15, 2010, 06:22:03 am »

Quote from: nemo on July 14, 2010, 08:45:44 pm

Code: [Select]
.SPRITE . header DiagnosticOff . turn off indicator/done 10->X->Y . initialize sprite position [3C7EFFFFFFFF7E3C->Pic0 . squares are for squares. therefore, a black circle is stored to pic0. Repeat getKey(15) . repeat until clear is pressed X+getkey(3)-getkey(2)->X . movement Y+getkey(1)-getkey(4)->Y . code Pt-Change(X,Y,Pic0 . draw sprite to buffer DispGraph . display what's on the buffer Pt-Change(X,Y,Pic0 . draw same sprite to buffer. since it's pt-change, the sprite is erased on the buffer, leaving no End . residue from movement. ClrHome . clear the screen, move cursor to upper left corner of the screen. ClrDraw . clear the buffer.
you can use a subroutine for pt-change() if those 10 bytes you save are really important to you.

Thanks! but how comes it doesn't flicker? because every time Clear is not pressed it redraws the sprite...

LordConiupiter · « **Reply #12 on:** July 15, 2010, 06:35:22 am »

that is because you don't clear the screen, but send directly the new data you want to it. The buffer flickers, but the screen just displays the bufferdata when it is sent to it.

matthias1992 · « **Reply #13 on:** July 15, 2010, 06:57:17 am »

but doesn't that eventually cause memory fatigue?

Quigibo · « **Reply #14 on:** July 15, 2010, 07:03:30 am »

The only time the screen changes is when you use "DispGraph". The buffer itself is not the screen, its just a place in memory like a program or a variable. Since the majority of commands draw things to this buffer location instead of the screen nothing actually happens to the LCD screen at all. It just stays the way it is (no flickering). The only time the display physically changes is when you use the DispGraph command which looks at the buffer and copies whatever's there to the screen. It copies the data so fast in fact, that it appears the entire screen was updated instantly. Once the screen has been updated with the DispGraph command, it will stay that way until the next DispGraph command so you are free to do whatever you want to the buffer in the mean time including clearing it and redrawing all the sprites.

Author Topic: Total noob question (Read 19611 times)

matthias1992

Total noob question

calcdude84se

Re: Total noob question

Magic Banana

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jsj795

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Magic Banana

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matthias1992

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jsj795

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LordConiupiter

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Magic Banana

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nemo

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shmibs

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matthias1992

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LordConiupiter

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matthias1992

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Quigibo

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