Off screen problem - GameCreators Forum

Author

Message

Bankzy10

15

Years of Service

User Offline

Joined: 29th Jan 2009

Location: Planet DarkBasic - Learning the tricks

Posted: 6th Jun 2009 18:30

Link

I have a spaceship that goes off the screen and was wondering how I stopped it from leaving the screen. The problem is only with it going off the top and bottom of the screen (it doesn't move left or right). How can I stop it? My spaceship is 90 by 37 and is located on the left side of the screen (its the background that scrolls to allow it to look like its moving right).

Thanks in advance, Bankzy10 =]

Back to top

Profile PM Email

Grog Grueslayer

Valued Member

19

Years of Service

User Offline

Joined: 30th May 2005

Playing: Green Hell

Posted: 6th Jun 2009 19:53

Link

You just check to see if the spaceship is beyond the limits before you show it. If it is outside of the limits you change the coordinates to within the limits.

+ Code Snippet

` Make a small box and grab the image
ink rgb(0,255,0),0
box 0,0,20,20
get image 1,0,0,100,100,1

do

 ` Get the x and y coordinates from the mouse
 x=mousex()
 y=mousey() 
 
 ` Limit the x coordinate to between 100 and 540
 if x<100 then x=100
 if x>540 then x=540
 
 ` Limit the y coordinate to between 100 and 340
 if y<100 then y=100
 if y>340 then y=340
 
 ` Show the sprite
 sprite 1,x,y,1

loop

Back to top

Profile PM Email

Bankzy10

15

Years of Service

User Offline

Joined: 29th Jan 2009

Location: Planet DarkBasic - Learning the tricks

Posted: 6th Jun 2009 22:02 Edited at: 8th Jun 2009 01:28

Link

How would you do it with keyboard inputs though as that done with where the mouse cursor is. Is there no statment for something like this:

If SPRITE NUMBER < 640, 0 THEN move back 37 (as the image is 37 pixels high).

640 Pixels
____________________
-/------------------|
--------------------| 4
-|--/___Spaceship---| 8
/-|/----------------| 0
--------------------| Pixels
-/------------------|
____________________|

The spaceship doesn't move to the right or left. It moves up and down. The ship is 90 X 37 pixels if that helps. It all works by Keyboard inputs - the up and down arrow buttons.

Back to top

Profile PM Email

vidmouse

15

Years of Service

User Offline

Joined: 28th Apr 2009

Location:

Posted: 15th Jun 2009 22:10

Link

Is this topic still live? My posts are delayed b/c I'm a noobie poster. It seems to me that you essentially have it, except that you need to check if the sprite location, not the sprite number is less than 0 or greater than 640:

+ Code Snippet

spriteposition_y = sprite y(sprite_number)

if spriteposition_y < 0
   spriteposition_y = 0
endif

if spriteposition_y > 640
   spriteposition_y = 640
endif

sprite sprite_number,spriteposition_x,spriteposition_y,sprite_image_number

Vidmouse's Software: http://www.freewebs.com/vidmouse/software.htm

Back to top

Profile PM

Bankzy10

15

Years of Service

User Offline

Joined: 29th Jan 2009

Location: Planet DarkBasic - Learning the tricks

Posted: 18th Jun 2009 23:59 Edited at: 19th Jun 2009 00:28

Link

So I would put it like this into my code?

+ Code Snippet

Do
spriteposition_x = sprite x(1)
spriteposition_y = sprite y(1)
`39 because my spaceship is 90x37 pixels
if spriteposition_y < 0
   spriteposition_y = 0
endif

if spriteposition_y > 443
   spriteposition_y = 443
endif

sprite 1,spriteposition_x,spriteposition_y,1
loop

Is that right? Or have I messed up with something?

EDIT: I have tried it and it works. The only problem is that it lags the game quiet abit, where when you hit the top and bottom of the screen it freezes for a second or so. It has a sync after that code, but still has the lag issue. Is there anything else I can do? Maybe run it from a sub?

Thanks, Bankzy10

Back to top

Profile PM Email

Grog Grueslayer

Valued Member

19

Years of Service

User Offline

Joined: 30th May 2005

Playing: Green Hell

Posted: 19th Jun 2009 02:55

Link

It's hard to say without more code. If you have a DO/LOOP exactly like your last code snip that may be the cause because there is no way to leave the DO/LOOP. If the SYNC is outside of that DO/LOOP it'll never SYNC again.

Back to top

Profile PM Email

Bankzy10

15

Years of Service

User Offline

Joined: 29th Jan 2009

Location: Planet DarkBasic - Learning the tricks

Posted: 19th Jun 2009 11:35

Link

This is my entire do loop that the code is located in. At the beginning the code is for my scrolling background, then my scoring and life text and then its the code from above. As you can see, it has the sync of it.

do
			rem if rightkey()=1
				set current bitmap 2
				offset= offset+1
				for i = 1 to 640
			   	paste image  x(i+offset),i,0
				next i
			rem endif

set current bitmap 0
			copy bitmap 2,0
			
rem Lifes left text on the screen
set text size 10
ink rgb(255,255,255),0
text 10,465,"Lifes Left:"

rem Score text on the screen
set text size 10
ink rgb(255,255,255),0
text 10,15,"Score:"

if upkey()=1 then ypos=ypos-5
			if downkey()=1 then ypos=ypos+5
         rem Update sprite
			sprite 1,xpos,ypos,1

spriteposition_x = sprite x(1)
spriteposition_y = sprite y(1)

`39 because my spaceship is 90x37 pixels
if spriteposition_y < 0
   spriteposition_y = 0
endif

if spriteposition_y > 443
   spriteposition_y = 443
endif

`1 is the sprite number and sprite image number is 1 too.
sprite 1,spriteposition_x,spriteposition_y,1

sync

if spacekey()>0
			gosub fire
		endif

rem Refresh screen now
		rem SYNC : SLEEP 20

sprite 5, xalien,yalien,3
xalien=xalien-1
rem if xalien<160
rem delete sprite 5
rem endif

if sprite collision(1,5)>0 then DELETE BITMAP 5
		loop

+ Code Snippet

		do
			rem if rightkey()=1
				set current bitmap 2
				offset= offset+1
				for i = 1 to 640
			   	paste image  x(i+offset),i,0
				next i
			rem endif

			set current bitmap 0
			copy bitmap 2,0
			
rem Lifes left text on the screen
set text size 10
ink rgb(255,255,255),0
text 10,465,"Lifes Left:"

rem Score text on the screen
set text size 10
ink rgb(255,255,255),0
text 10,15,"Score:"




			if upkey()=1 then ypos=ypos-5
			if downkey()=1 then ypos=ypos+5
         rem Update sprite
			sprite 1,xpos,ypos,1

spriteposition_x = sprite x(1)
spriteposition_y = sprite y(1)


`39 because my spaceship is 90x37 pixels
if spriteposition_y < 0
   spriteposition_y = 0
endif

if spriteposition_y > 443
   spriteposition_y = 443
endif

`1 is the sprite number and sprite image number is 1 too.
sprite 1,spriteposition_x,spriteposition_y,1

sync

		if spacekey()>0
			gosub fire
		endif


		rem Refresh screen now
		rem SYNC : SLEEP 20


sprite 5, xalien,yalien,3
xalien=xalien-1
rem if xalien<160
rem delete sprite 5
rem endif

if sprite collision(1,5)>0 then DELETE BITMAP 5
		loop

If had a little fiddle around with it, but it's still doing the same - any suggestions?

Thanks, Bankzy10

Back to top

Profile PM Email

Grog Grueslayer

Valued Member

19

Years of Service

User Offline

Joined: 30th May 2005

Playing: Green Hell

Posted: 19th Jun 2009 12:27

Link

You should put the SYNC at the bottom just before LOOP. Putting it there makes sure anything in the DO/LOOP will be SYNCed at the same time. The text size and the color can be put outside of the DO/LOOP (since they don't change) and you only need one of each. COPY BITMAP may be causing lag too. Since you're just copying the bitmap of a pasted image you could just paste the image to bitmap zero and avoid switching screens and copying the bitmap. Hopefully that'll de-lag your game.

Back to top

Profile PM Email

Sorry your browser is not supported!

2D All the way! / Off screen problem