I wrote earlier about wanting to have certain sprites (enemies, locked doors, etc), have state that is persistent in a number of levels – screen-local (respawning when leaving/entering a room), map-local (enemies don’t respawn tiill you leave a dungeon and re-enter), and global (bosses stay dead, unlocked doors stay open!)
I kind of figured out a way to deal with this. I never sucked it up to figure out some stuff with the wonderful DAME exporter (an awesome map editor for flixel/flashpunk/etc games) and its lua exporter business…but then I did, sort of, at least enough to make it kind of do what I wanted.
Every map I make is split into grids, because that’s how I want the camera to work. I also only want to load sprites on a certain grid. Currently when I export the sprites from DAME, they end up all under one XML <level> node. This is fine, but on a big map when I want to load certain sprites for a grid, I’d have to calculate every single object’s grid x and y coordinates!! Although that would probably work fine, that’s not as nice. So, I did the following:
After embedding the XML from DAME into my game, I iterate through its <level> nodes (remember, level nodes just correspond to contiguous “areas” in my game – perhaps a floor of a dungeon, someone’s house, etc.). I create a new XML (one that will be serialized/saved and later checked to determine state of a room) object, and create a new <level> node. For every object (enemy, door, etc) in the <level> node of the DAME XML, I convert its x and y coordinates into grid-coordinates, so [0,screen_width) -> 0, [screen_width,2*screenwidth) -> 1, etc. I check if I’ve already added a <grid> node to my new <level> node, if so, I append the object to the grid node, otherwise, make a new grid node, append it to the level node, and append the object to the grid node.
Conceptually I guess this wasn’t too unwieldy, but it took a little time to figure out the syntax and what not.
This DAME-generated XML:
<root> <level name="Dungeon_Test"> <Slime x="96" y="32" p="1" alive="true" /> <Slime x="128" y="32" p="1" alive="true" /> <Slime x="80" y="32" p="1" alive="true" /> <Slime x="176" y="224" p="1" alive="true" /> <Slime x="224" y="368" p="1" alive="true" /> <Slime x="80" y="256" p="1" alive="true" /> <Slime x="16" y="336" p="1" alive="true" /> <Slime x="32" y="352" p="1" alive="true" /> </level> <level name="Area_X"> <Slime x="80" y="80" p="1" alive="true" /> <Slime x="0." y="32" p="1" alive="true" /> <Slime x="16" y="112" p="1" alive="true" /> <Slime x="48" y="32" p="1" alive="true" /> <Slime x="48" y="80" p="1" alive="true" /> </level> </root>
is transformed to this XML (which will end up being serialized and used in the game):
<root>
<level name="Dungeon_Test">
<grid grid_x="0" grid_y="0">
<Slime x="96" y="32" p="1" alive="true"/>
<Slime x="128" y="32" p="1" alive="true"/>
<Slime x="80" y="32" p="1" alive="true"/>
</grid>
<grid grid_x="1" grid_y="1">
<Slime x="176" y="224" p="1" alive="true"/>
</grid>
<grid grid_x="1" grid_y="2">
<Slime x="224" y="368" p="1" alive="true"/>
</grid>
<grid grid_x="0" grid_y="1">
<Slime x="80" y="256" p="1" alive="true"/>
</grid>
<grid grid_x="0" grid_y="2">
<Slime x="16" y="336" p="1" alive="true"/>
<Slime x="32" y="352" p="1" alive="true"/>
</grid>
</level>
<level name="Area_X">
<grid grid_x="0" grid_y="0">
<Slime x="80" y="80" p="1" alive="true"/>
<Slime x="0." y="32" p="1" alive="true"/>
<Slime x="16" y="112" p="1" alive="true"/>
<Slime x="48" y="32" p="1" alive="true"/>
<Slime x="48" y="80" p="1" alive="true"/>
</grid>
</level>
</root>
By this chunk of AS3 code (FYI, there are some static thingies from me playing around calling this function from elsewhere, also saveXML needs to be referenced globally)
[Embed (source = '../xml/Seen.xml', mimeType = "application/octet-stream")] public static const EmbedXML:Class;
public static var embedXML:XML = new XML(new EmbedXML);
public static var saveXML:XML = <root> </root>;
public static function embed2saveXML():void {
var savelevel:XML; //Will be a level node for our saveXML tree
var o:XML; //Generic object XML
var level:XML; //For each "level" (house/dungeon/whatever)
var grid:XML; //Represents a "grid"
var grid_exists:Boolean; // Set to true when an existing grid is found
// while iterating through some level's grids
var name:String;
var x:int; var grid_x:int;
var y:int; var grid_y:int;
//Every level corresponds to a floor of a dungeon,
//a house, the world map, etc.
for each (level in embedXML.level) {
savelevel = <level/>;
savelevel.@name = level.@name;
// These are all the DAME objects.
for each (o in level.*) {
//convert XY into Grid X,Y.
x = parseInt(o.@x);
y = parseInt(o.@y) + HEADER_HEIGHT;
grid_x = x / Registry.SCREEN_WIDTH_IN_PIXELS;
grid_y = y / Registry.SCREEN_HEIGHT_IN_PIXELS;
// Append the object "o" to the grid node if it already exists.
grid_exists = false;
for each (grid in savelevel.grid) {
if (grid.@grid_x == grid_x.toString() && grid.@grid_y == grid_y.toString()) {
grid.appendChild(o);
grid_exists = true;
break;
}
}
// Otherwise, create a new grid node and append "o" to it.
if (!grid_exists) {
grid = <grid/>
grid.@grid_x = grid_x.toString();
grid.@grid_y = grid_y.toString();
grid.appendChild(o);
savelevel.appendChild(grid);
}
}
//Finally, append the transformed level node to the serialized XML.
saveXML.appendChild(savelevel);
}
}
Is there a better way to do this? Probably! But this works…it seems. Of course, more attributes will have to be added and what not to deal with state, but this is a good base for that.
ambient-melodic 