Easy 2D Scrooling Help Plz?

BlitzMax Forums/BlitzMax Beginners Area/Easy 2D Scrooling Help Plz?

Joestick

(Posted 2009) [#1]

Hi,

I have a black map(space 10.000 x 10.000) and 2 Objects,
the first one(A) beginning on left side on the map and the second(B)
on the right side.

Like This:

----------------------------------------------------
|A................................................B|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
|..................................................|
----------------------------------------------------

Now when i move my object A (A.x = A.X+1) everything is ok!!
the coords of B are X = 1000 and Y = 0
How i copy the viewport of my object A is the problem.

I try:

SetViewPort
SetOrign

But some thing is wrong.

Help me and thank's

xlsior

(Posted 2009) [#2]

The viewport limits the drawable portion of the screen to a subset of the screen, it doesn't move a larger-than-the-screen image around.

For what you're trying to do, people would typically use a tile-system: you'd have to figure out which part of your map is visible, and draw only draw those portions (off-set to the actual screen coordinates)

ImaginaryHuman

(Posted 2009) [#3]

If you use SetOrigin to change the origin, you would then have to draw/copy from 0,0 to width,height and NOT from the A object's X/Y coord.

Otherwise, if you keep the origin at 0,0, then you'd want to draw copy from the object's X,Y to X+width,Y+height.

I don't think Viewport is going to help you much - it confines the drawing to a smaller section of the screen. It sounds like you want to scroll a game world larger than the screen?

Derron

(Posted 2009) [#4]

Better use something like:

type TTiles
 field x:float, y:float

 method Draw(wx:float, wy:float)
    'wx and wy are starting points of world - local coordinates get added here
    'add optional checks wether draw etc. is needed (wx+x +imgwidth>0 and wx+x < screenwidth, same for y and height)
    DrawOval(wx + x, wy+y, 2,2)
 end Method
End Type

global worldX:float = 0.0
global worldY:float = 0.0
global testtile:TTiles = new TTiles
testtile.x = 10
testtile.y = 5

repeat
 cls
 testtile.draw(worldX, worldY)
 if keyhit(KEY_LEFT) then worldX :-1
 if keyhit(KEY_RIGHT) then worldX :+1
 if keyhit(KEY_UP) then worldY :-1
 if keyhit(KEY_DOWN) then worldY :+1
 flip
until AppTerminate()

Code is not tested, but will show the principles.

bye MB

Dabhand

(Posted 2009) [#5]

If your new to programming, I'd suggest taking a peek at mappy:-

http://www.tilemap.co.uk/mappy.php

Then have a looksy at Gmans BlitzMax Mappy module, which is nicely located here:-

http://www.gprogs.com/viewtopic.php?id=26

First scroller I ever made was with mappy (Blitz2D), learnt a lot too! :)

Dabz