feat: Add json sdf font parser

hxd/fmt/bfnt/FontParser.hx

@@ -40,6 +40,13 @@ class FontParser {
 
 		font.baseLine = 0;
 
+		// Json Format generated by https://github.com/Chlumsky/msdf-atlas-gen
+		if(bytes.getString(0,1) == "{") {
+				resolveTileSameName();
+				return hxd.fmt.bfnt.JsonFontParser.parse(bytes,tile);
+		}
+
+
 		switch( bytes.getInt32(0) ) {
 		case 0x544E4642: // Internal BFNT
 			return hxd.fmt.bfnt.Reader.parse(bytes, function( tp : String ) { resolveTileWithFallback(tp); return tile; });

hxd/fmt/bfnt/JsonFontParser.hx

@@ -0,0 +1,85 @@
+package hxd.fmt.bfnt;
+
+import h2d.Font.FontChar;
+import haxe.Json;
+using thx.Arrays;
+
+typedef JsonFontAtlas = {
+	var type:String;
+	var distanceRange:Int;
+    var size:Int;
+	var width:Int;
+	var height:Int;
+}
+
+typedef JsonFontMetrics = {
+	var emSize:Float;
+	var lineHeight:Float;
+	var ascender:Float;
+	var descender:Float;
+	var underlineY:Float;
+	var underlineThickness:Float;
+}
+
+typedef JsonFontBounds = {
+	var left:Float;
+	var bottom:Float;
+	var right:Float;
+	var top:Float;
+}
+
+typedef JsonFontGlyph = {
+	var unicode:Int;
+	var advance:Float;
+	var planeBounds:JsonFontBounds;
+	var atlasBounds:JsonFontBounds;
+}
+
+
+typedef JsonFontFormat = {
+	var atlas:JsonFontAtlas;
+	var metrics:JsonFontMetrics;
+	var glyphs:Array<JsonFontGlyph>;
+}
+
+@:access(h2d.Font)
+class JsonFontParser {
+
+	public static inline function parse(bytes : haxe.io.Bytes,tile) : h2d.Font {
+        final font = new h2d.Font(null,0);
+        final glyphs = font.glyphs;
+        font.tile = tile;
+
+        final data:JsonFontFormat = Json.parse(bytes.getString(0,bytes.length));
+
+        font.size = data.atlas.size;
+		font.initSize = font.size;
+        font.distanceRange = data.atlas.distanceRange;
+        font.fieldType = data.atlas.type;
+
+        font.lineHeight = data.metrics.lineHeight * data.atlas.size * 0.5;
+
+		for(glyph in data.glyphs) {
+			final xadvance = data.atlas.size * glyph.advance;
+			if( glyph.atlasBounds != null && glyph.planeBounds != null ) {
+				final x = glyph.atlasBounds.left;
+				final y = data.atlas.height - glyph.atlasBounds.top;
+				final width = glyph.atlasBounds.right - glyph.atlasBounds.left;
+				final height = glyph.atlasBounds.top - glyph.atlasBounds.bottom;
+
+				final offsetX = glyph.planeBounds.left * data.atlas.size;
+				final offsetY = glyph.planeBounds.top * data.atlas.size;
+
+				final subTile = tile.sub(x,y,width,height,offsetX,-offsetY + data.atlas.size);
+				glyphs.set(glyph.unicode,new FontChar(subTile,xadvance));
+			} else {
+				final subTile = tile.sub(0,0,1,1,0,0);
+				glyphs.set(glyph.unicode,new FontChar(subTile,xadvance));
+			}
+
+		}
+
+		return font;
+	}
+
+}