I'm trying to make a grid-based level editor, and I need a giant white grid in the background that moves with the objects when the level scrolls, but isn't one huge image that's the size of the stage. Any ideas on how to do that?
Entity1037 wrote ...
2013/10/5
Create a grid that outlines squares where objects can be placed?
You can make the grid by setting the background of the world to an grid-cell-sized image that has a frame, with your world being of cell-size one. After that, you just need a scrolling engine with x and y scroll offsets and an array to keep track of where everything is at; so object would be located at (arrayX*gridSize+gridSize/2+scrollX, arrayY*gridSize+gridSize/2+scrollY).
Hope this helps. (+: DAN :+)
To scroll the background, take a grid-cell-sized image from the top-left corner of your current background and apply the scroll amounts to that image and re-apply the new image to set the background to.
For example, if you needed to scroll scrollingX along the x-axis and scrollingY along the y-axis:
int scrollAmtX = (scrollingX+gridSize)%gridSize; // wraps along x-axis int scrollAmtY = (scrollingY+gridSize)%gridSize; // wraps along y-axis GreenfootImage old = new GreenfootImage(gridSize, gridSize); old.drawImage(getBackground(), 0, 0); // the current grid-sized image GreenfootImage image = new GreenfootImage(gridSize, gridSize); image.drawImage(old, scrollAmtX, scrollAmtY); image.drawImage(old, scrollAmtX-gridSize, scrollAmtY); image.drawImage(old, scrollAmtX, scrollAmtY-gridSize); image.drawImage(old, scrollAmtX-gridSize, scrollAmtY-gridSize); setBackground(image); // move all objects by (objectRef.getX()+scrollingX, objectRef.getY()+scrollingY) scrollX += scrollingX; scrollY += scrollingY;
Actually, I have a scrolling engine already. I just need some way to make a 50 cell X 50 cell grid that moves with the objects (which can only be placed inside those grid spaces.
Here's my scrolling engine:
The player's coordinates are continually given to the engine by X.class, which uses getCoordinates(int x,int y){}
boolean autoScroll=true;
int xc=getWidth()/2;//X center of screen
int yc=getHeight()/2;//Y center of screen
int xX=xc;//X's X coordinate
int xY=yc;//X's Y coordinate
public void getCoordinates(int x, int y){xX=x; xY=y;}
int xcorrect=0;//How much world needs to be scrolled on the X-axis
int ycorrect=0;//How much world need to be scrolled on the Y-axis
int s=25;//How far from center X can stray before the screen scrolls
int xst=0;//How far the screen's x coordinate is away from start
int yst=0;//How far the screen's y coordinate is away from start
int rlimit=1000;
int llimit=1000;
int ulimit=500;
int dlimit=200;
public void setScrollingLimits(int right, int left, int up, int down){rlimit=right; llimit=left; ulimit=up; dlimit=down;}
public void scrollingEngine(){
xcorrect=0;
ycorrect=0;
if (autoScroll==true){
//Figure out how far away X is from the scrolling margin, if at all
if (xX<xc-s){xcorrect=xc-s-xX;}else if (xX>xc+s){xcorrect=xc+s-xX;}
if (xY<yc-s){ycorrect=yc-s-xY;}else if (xY>yc+s){ycorrect=yc+s-xY;}
}
//Test if the scrolling boundries have been reached, and stop scrolling if they have
if (xst+-xcorrect>=rlimit){xcorrect=0; xst=rlimit;}
if (xst+-xcorrect<=-llimit){xcorrect=0; xst=-llimit;}
if (yst+-ycorrect>=dlimit){ycorrect=0; yst=dlimit;}
if (yst+-ycorrect<=-ulimit){ycorrect=0; yst=-ulimit;}
//Track the screen's scrolling
xst+=-xcorrect; //x-axis tracking
yst+=-ycorrect; //y-axis tracking
//Scroll world, if at all
((GridCoordinates)getObjects(GridCoordinates.class).get(0)).giveGridCoordinates(xcorrect,ycorrect);
if (xcorrect==0&&ycorrect==0)return;
scroll();
}
Class[] world = {Matter.class,Terrain.class,xbullets.class};
public void scroll(){
for (int i=0; i<world.length; i++){
List objects = getObjects(world[i]);
if (! objects.isEmpty()){
for (int o=0; o<objects.size(); o++){
Actor object = (Actor) objects.get(o);
object.setLocation(object.getX()+xcorrect,object.getY()+ycorrect);
}
}
}
}
Entity1037 wrote...
I just need some way to make a 50 cell X 50 cell grid that moves with the objects (which can only be placed inside those grid spaces.GreenfootImage cell = new GreenfootImage(50, 50); cell.setColor(java.awt.Color.white); cell.fill(); cell.setColor(java.awt.Color.gray); cell.drawRect(0, 0, 49, 49); setBackground(cell);
I'm having problems getting your code to work. I'm not exactly sure what those variables are suppose to represent in the first place, and the background ends up going really fast diagonally.
Nevermind, I got it!
ScrollingX and ScrollingY were the same thing as xcorrect and ycorrect.
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