Load Tileset file independently of a Map (#91)

* Functions to load/save tileset

* Add support for loading tilesets directly from TSX files, without maps.

* Address #35 by removing Save feature.

Concerns were around using pointer-to-bool to support omitting default-true
bools during save.

Removed the Save feature to get past that issue, hoping to get at least part
of this PR submitted after 4 years.

* Fix naming of LoadTilesetReader functions to match local convention.

---------

Co-authored-by: Metalblueberry <metalblueberry@gmail.com>

Author: hegh

assets/tilesets/testLoadTileset.tsx

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<tileset version="1.2" tiledversion="1.2.3" name="ProjectUtumno_full" tilewidth="32" tileheight="32" tilecount="6080" columns="64">
+ <image source="ProjectUtumno_full.png" width="2048" height="3040"/>
+ <properties>
+  <property name="testTilesetProperty" value="valueOfTilesetProperty"/>
+ </properties>
+ <tile id="116" type="door">
+  <properties>
+   <property name="testTileProperty" type="int" value="7"/>
+  </properties>
+ </tile>
+</tileset>

assets/tilesets/testLoadTilesetTile.tsx

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<tileset version="1.2" tiledversion="1.2.3" name="ProjectUtumno_full" tilewidth="32" tileheight="32" tilecount="6080" columns="64">
+ <image source="ProjectUtumno_full.png" width="2048" height="3040"/>
+ <tile id="464">
+  <objectgroup draworder="index">
+   <object id="1" x="-0.25" y="17.75" width="32.375" height="6.125"/>
+  </objectgroup>
+  <animation>
+   <frame tileid="75" duration="500"/>
+   <frame tileid="76" duration="500"/>
+  </animation>
+ </tile>
+</tileset>

tiled.go

@@ -43,6 +43,20 @@ func LoadFile(fileName string, options ...LoaderOption) (*Map, error) {
 	return l.LoadFile(fileName)
 }
 
+// LoadTilesetReader loads a tileset from an io.Reader.
+// baseDir is used to locate relative paths to additional tileset data; default
+// is currend directory if empty.
+func LoadTilesetReader(baseDir string, r io.Reader, options ...LoaderOption) (*Tileset, error) {
+	l := newLoader(options...)
+	return l.LoadTilesetReader(baseDir, r)
+}
+
+// LoadTilesetFile loads a tiled map in TSX format from a file.
+func LoadTilesetFile(fileName string, options ...LoaderOption) (*Tileset, error) {
+	l := newLoader(options...)
+	return l.LoadTilesetFile(fileName)
+}
+
 // loader provides configuration on how TMX maps and resources are loaded.
 type loader struct {
 	// A FileSystem that is used for loading TMX files and any external
@@ -106,3 +120,30 @@ func (l *loader) LoadFile(fileName string) (*Map, error) {
 	dir := filepath.Dir(fileName)
 	return l.LoadReader(dir, f)
 }
+
+// LoadTilesetFile loads a tileset in TSX format from a file.
+func (l *loader) LoadTilesetFile(fileName string) (*Tileset, error) {
+	f, err := l.open(fileName)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	dir := filepath.Dir(fileName)
+	return l.LoadTilesetReader(dir, f)
+}
+
+// LoadTilesetReader loads a .tsx file into a Tileset structure
+func (l *loader) LoadTilesetReader(baseDir string, r io.Reader) (*Tileset, error) {
+	d := xml.NewDecoder(r)
+
+	t := &Tileset{
+		baseDir: baseDir,
+	}
+	if err := d.Decode(t); err != nil {
+		return nil, err
+	}
+
+	t.SourceLoaded = true
+	return t, nil
+}

tmx_tileset_test.go

@@ -24,6 +24,8 @@ package tiled
 
 import (
 	"image"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -165,3 +167,124 @@ func TestGetTileRect(t *testing.T) {
 		})
 	}
 }
+
+var testLoadTilesetFile = &Tileset{
+	baseDir:  ".",
+	Columns:  64,
+	FirstGID: 0,
+	Image: &Image{
+		Format: "",
+		Data:   nil,
+		Height: 3040,
+		Width:  2048,
+		Source: "ProjectUtumno_full.png",
+		Trans:  nil,
+	},
+	Margin: 0,
+	Name:   "ProjectUtumno_full",
+	Properties: Properties{
+		{
+			Name:  "testTilesetProperty",
+			Value: "valueOfTilesetProperty",
+		},
+	},
+	Source:       "",
+	SourceLoaded: true,
+	Spacing:      0,
+	TerrainTypes: nil,
+	TileCount:    6080,
+	TileHeight:   32,
+	TileOffset:   nil,
+	TileWidth:    32,
+	TiledVersion: "1.2.3",
+	Tiles: []*TilesetTile{
+		{
+			ID:           116,
+			Type:         "door",
+			Animation:    nil,
+			Image:        nil,
+			ObjectGroups: nil,
+			Probability:  0,
+			Properties: Properties{
+				{
+					Name:  "testTileProperty",
+					Type:  "int",
+					Value: "7",
+				},
+			},
+			Terrain: "",
+		},
+	},
+	Version: "1.2",
+}
+
+var testLoadTilesetTileFile = &TilesetTile{
+	ID: 464,
+	Animation: []*AnimationFrame{
+		{
+			Duration: 500,
+			TileID:   75,
+		},
+		{
+			Duration: 500,
+			TileID:   76,
+		},
+	},
+	Image: nil,
+	ObjectGroups: []*ObjectGroup{
+		{
+			ID:        0,
+			Color:     nil,
+			DrawOrder: "index",
+			Name:      "",
+			Objects: []*Object{
+				{
+					GID:        0,
+					Ellipses:   nil,
+					Height:     6.125,
+					ID:         1,
+					Name:       "",
+					PolyLines:  nil,
+					Polygons:   nil,
+					Properties: nil,
+					Rotation:   0,
+					Text:       nil,
+					Type:       "",
+					Visible:    true,
+					Width:      32.375,
+					X:          -0.25,
+					Y:          17.75,
+				},
+			},
+			OffsetX:    0,
+			OffsetY:    0,
+			Opacity:    1,
+			Properties: nil,
+			Visible:    true,
+		},
+	},
+}
+
+func TestLoadTileset(t *testing.T) {
+	tsxFile, err := os.Open(filepath.Join(GetAssetsDirectory(), "tilesets/testLoadTileset.tsx"))
+	assert.Nil(t, err)
+	defer tsxFile.Close()
+
+	tsx, err := LoadTilesetReader(".", tsxFile)
+	assert.Nil(t, err)
+
+	assert.Equal(t, testLoadTilesetFile, tsx)
+}
+
+func TestLoadTile(t *testing.T) {
+	tsxFile, err := os.Open(filepath.Join(GetAssetsDirectory(), "tilesets/testLoadTilesetTile.tsx"))
+	assert.Nil(t, err)
+	defer tsxFile.Close()
+
+	tsx, err := LoadTilesetReader(".", tsxFile)
+	assert.Nil(t, err)
+	assert.Len(t, tsx.Tiles, 1)
+
+	tile := tsx.Tiles[0]
+	assert.Equal(t, testLoadTilesetTileFile, tile)
+}