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Post by memorydump on Jan 20, 2011 23:16:35 GMT -5
I'm never going to be an excellent coder, but am trying what I can. I recently thought I could try to make a Zelda engine by just taking examples that have been given already and try to edit them and hopefully get my desired result. That's basically my whole plan for this project, because I don't have the time to learn programming much besides the basics, and this is just something to pass the time when I'm bored to see if I can actually make something on the Genesis. So hopefully no one attacks me when it appears I want all the work done for me, since it's admittedly what I'm doing and I'm not too serious about this, it's just for fun =p So far it's of course difficult since I have no understanding of programming and am just doing guess work when messing with code. What my goal is right now is to just get a camera that follows the sprite on screen. I'm using moon's excellent Soleil example, which comes from here devster.proboards.com/index.cgi?action=display&board=basiegaxorz&thread=603&page=1#5815I'm combining this with oompa loopa's Gelda example, just taking the sprite from it and the basic "if...then..else" commands that move the camera with the sprite depending on its position. The problem of course for me since I am not good at programming is that I can't figure out how to integrate this coding into the Soleil example. I've been doing lots of things and so far I can't seem to get the camera to follow the sprite, but just get it to respond to me pressing the direction keys. What I'm doing at the moment is just to get the sprite moving up and the camera going with it when it reaches a certain position. Here's what the Gelda code has: while 1
sleep 1
j = joypad()
if j.0 then ' Up
if (gelda_y-2-camera_y) <= 64 then
gosub scroll_map_up
else
gelda_y = gelda_y - 2
gosub update_gelda_sprite
endifThe main part of the Soleil code I guessed I should be trying to rewrite in combination for that is this: while 1
joypad = joypad(0)
camera(0,1) = (joypad.3-joypad.2)*12
camera(1,1) = (joypad.1-joypad.0)*12
camera(0,0)+= camera(0,1)
camera(1,0)+= camera(1,1)
cx = divide(camera(0,0),16)
cy = divide(camera(1,0),16)
render cx ,cy,cx ,cy+13
render cx+20,cy,cx+20,cy+13
render cx,cy ,cx+20,cy
render cx,cy+14,cx+20,cy+14
scroll left,camera(0,1)
scroll up,camera(1,1)
sleep 1
wendI'm guessing camera(1,1) = (joypad.1-joypad.0)*12 is what I'm wanting to mess with so i can instead of getting the camera to move when you press the up key, I get it to move when the sprite is at the right position. So I guessed up something dirty and ridiculous like this: movesprite gelda_sprite, 128+gelda_x, 128+gelda_y
while 1
joypad = joypad(0)
if joypad.0 then ' Up
if (gelda_y-2-cy) <= 64 then
camera(1,1) = (joypad.1-joypad.0)*12
else
gelda_y = gelda_y - 2
gosub update_gelda_sprite
endif
endif
I can move the sprite up until it reaches the <= 64 position, but once it gets past that the screen keeps scrolling up. I've tried tons of different things too, too many to remember or list, map keeps looping crazy, link flies off the screen, it's all not the desired result of course. So I'm wondering if anyone can give me a clue on how I can get a properly Zelda Link to the Past type thing going on here where the camera will follow the sprite when it should. I'm guessing it's not all that complex a thing to put into here, I'm just not figuring it out since I mainly can't figure out how to get the camera to stop being controlled by the D-pad but instead controlled by the sprites position, and to follow the sprite on when it moves. Hope I made sense, go easy on me  |
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Post by Deleted on Jan 21, 2011 9:01:25 GMT -5
I'm assuming you're referring to Zelda 1 (or maybe A link to the past?). If I remember correctly, both use a similar screen by screen engine.
I know zelda 1 is purely screen by screen, so we'll start with that since it's the easiest and I think a link to the past is screen by screen, but with scrolling as well (it's been a while since I played it).
Anyway, if you take out the soleil main loop and put your character sprite in there, use the joypad functions to move the sprite around the screen. When your sprite reaches X or Y on the screen, use the soliel functions to scroll to desired screen, while moving the character sprite to the starting origin of that screen.
Edit: I should have read the entire post. If you want your sprite in the center of the screen, just put him there and the scrolling will happen while the sprite sits there.
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Post by Deleted on Jan 21, 2011 14:34:55 GMT -5
memorydumpFirst off, as mentioned in the original post, the "Soleil" example is highly unoptimized and purely meant to explain the concept behind a scrolling map. You don't want to use that code in a actual project. Anyway .. the world map in "Link to the Past" is divided up in cells of 512x512 pixels ( see image below ). Depending on your character's position you can check whether the camera frustum overlaps a cell border. If this is the case, check whether the neighboring cell in question is a different "area" or not. If it is different, clamp the camera to the cell border ( and do a sweep animation when crossing such border ).  Good luck with that 
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Post by memorydump on Jan 21, 2011 21:36:20 GMT -5
Thanks for the help, I'm not sure I get everything though, my main gripe at the moment is figuring out which part of the Soliel example is considered the main code. In the original Gelda example, when the camera needs to move with the sprite it jumps to a separate subroutine for scrolling the map in the direction you're headed. I don't see any one piece of code in in the Soliel example that I can have it jump to to move the screen with the sprite. And just to be clear, I'm trying for a Link to the Past type thing, not like the original Zelda i.e the camera follows the sprite on screen. BTW if it's not obvious, I'm trying to make a little Link to the Past clone =p memorydumpFirst off, as mentioned in the original post, the "Soleil" example is highly unoptimized and purely meant to explain the concept behind a scrolling map. You don't want to use that code in a actual project. Anyway .. the world map in "Link to the Past" is divided up in cells of 512x512 pixels ( see image below ). Depending on your character's position you can check whether the camera frustum overlaps a cell border. If this is the case, check whether the neighboring cell in question is a different "area" or not. If it is different, clamp the camera to the cell border ( and do a sweep animation when crossing such border ). Good luck with that Heh, keep in mind when I said have everyone do all the work for me I was referencing the fact I'll be using lots of examples given around here, I'm not going to specifically ask someone to write a whole part of the game for me each time when I need something =p But admittedly lots of newbies use the examples given on this board as the basis starting their games. I'm aware your camera is unoptimized, but it's surely the fastest one I've seen so far, any other examples lag. Anyway I didn't mean to sound too bad there, i just notice lots of people on this board ask for help and ask specifically for examples, when its clear they don't understand how to do it themselves at all so they're practically saying make it for them since they can't. So I thought it better to just be honest about where I stand in my skills instead of following that trend  BTW, did you make that Zelda map yourself? Cool example, I mostly guessed all of what you said, including noticing that all the maps are 512x512 cells. Just the fact I'm a total newbie at programming makes it so i have no idea how to really get any of the work done, but I'm trying. |
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Post by Deleted on Jan 22, 2011 14:44:51 GMT -5
memorydumpAttached is a example how the camera behavior works. I've borrowed part of "Link's Awakening" map ( easier to convert ) but used the "Link to the Past" camera technique ( without the transition, and a border of 0 pixels ). As usual, highly unoptimized and purely for learning purposes. The map is divided up into the following areas.  Don't worry, everybody can do whatever they want obviously  Attachments:
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Post by memorydump on Jan 22, 2011 21:08:54 GMT -5
Thanks for the example again. I've been searching the net also for other people that may have written a Zelda engine in QBasic and the like, it's proving somewhat useful since they also give examples and it's not too complex to translate for BasiEgXorz  |
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Post by Deleted on Jan 22, 2011 22:08:25 GMT -5
The big difference you'll find in qbasic vs basiegxorz is there's no scroll commands in qbasic, and it's all done through a pixel scrolling engine. We basiegxorz coders are lucky that we have that option, as it strips out a LOT of coding to be done. Aside from that (and graphic manipulation), there's a lot of similarities, so if you can program logic in one, you can in the other.
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Post by memorydump on Jan 22, 2011 23:30:36 GMT -5
Quick question because I can't get anything to come up on Google, what does += mean exactly?
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Post by Deleted on Jan 23, 2011 0:06:16 GMT -5
a = 1
a+=2
print a
(should display 3)
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Post by Deleted on Jan 23, 2011 11:26:20 GMT -5
Also worth noting is that even though "x=x+1" and "x+=1" result in the same, the latter compiles much nicer.
' x=x+1
clr.l d0
move.w (__INTEGER_x),d0
add.w #1,d0
move.w d0,(__INTEGER_x) ' x+=1
move.l #1,d0
add.w d0,(__INTEGER_x)
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Post by Deleted on Jan 23, 2011 12:45:21 GMT -5
Nice to know moon, thanks for that additional info |
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Post by memorydump on Feb 10, 2011 5:08:19 GMT -5
Alright, I searched around the net a bit and found a pixel scrolling engine for qbasic that I've been trying to adapt to bex. You'll see it's not perfectly adapted for it yet(heck, I don't think I know what I'm doing, just trying my luck =p), but as it is I'd think it wouldn't bring up this error. It keeps complaining about an If statement without endif, but I don't see any statements in the code that require me to do an endif, it seems perfectly fine the way it is. Any help? I realize the thing as a whole wouldn't compile perfectly as is, but I usually try compiling anyway time to time just so I can spot errors like this before making more code. Attachments:
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Post by sega16 on Feb 10, 2011 16:30:53 GMT -5
Try changing:
IF anim(til).frames > 1 THEN til = til + ((frames# / anim(til).delay) % (anim(til).frames))
To:
IF anim(til).frames > 1 THEN
til = til + ((frames# / anim(til).delay) % (anim(til).frames))
ENDIF
And do the same for all other ifs
if ShowMapx<0 then
ShowMapx=0 'If the camera is off the map in the negative area, recenter
endif
if ShowMapy<0 then
ShowMapy=0 'it at 0,0
endif
IF ShowMapx>(MapSizeX-160) then
ShowMapX=(MapSizeX-160) 'if the camera is too far, clip it at
'the max point
endif
IF ShowMapy>(MapSizeY-96) then
ShowMapY=(MapSizeY-96)
endif
And so on...
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Post by memorydump on Feb 10, 2011 21:46:15 GMT -5
That seemed to work. I don't understand why though, what was bad with the original code? For example in the zelda example moon gave above, there's code like this: if player_x<4 then player_x=4 if player_y<4 then player_y=4 if player_x>316 then player_x=316 if player_y>188 then player_y=188 And yet neither of those require endif. So why is it needed in my example? Edit: It seems like it has something to do with how you put the symbols together. If I do if ShowMapx<0 then ShowMapx=0 with no spaces between the equals sign or the less than sign, it brings no errors. I can't get it to work with this though: if ShowMapx>(MapSizeX - 160) then ShowMapX=(MapSizeX- 160) 'if the camera is too far, clip it at
endifThat still brings up an error. Still lost what,s wrong, but I thought putting them together might work after I looked at this topic: www.assemblergames.com/forums/showthread.php?t=30681Is it really interpreted differently depending on spaces or not? |
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Post by sega16 on Feb 11, 2011 16:28:51 GMT -5
To always get "Proper" if statement do it like this
if (compare statement) then (Nothing after then skip a line)
(code goes here)
(else statement and code if you want)
ENDIF
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