tmx_object.go

/*
Copyright (c) 2017 Lauris Bukšis-Haberkorns <lauris@nix.lv>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

package tiled

import (
	"encoding/xml"
	"errors"
	"strconv"
	"strings"
)

var (
	// ErrInvalidObjectPoint error is returned if there is error parsing object points
	ErrInvalidObjectPoint = errors.New("tiled: invalid object point")
)

// ObjectGroup is in fact a map layer, and is hence called "object layer" in Tiled Qt
type ObjectGroup struct {
	// The name of the object group.
	Name string `xml:"name,attr"`
	// The color used to display the objects in this group.
	Color string `xml:"color,attr"`
	// The opacity of the layer as a value from 0 to 1. Defaults to 1.
	Opacity float32 `xml:"opacity,attr"`
	// Whether the layer is shown (1) or hidden (0). Defaults to 1.
	Visible bool `xml:"visible,attr"`
	// Rendering offset for this layer in pixels. Defaults to 0. (since 0.14)
	OffsetX int `xml:"offsetx,attr"`
	// Rendering offset for this layer in pixels. Defaults to 0. (since 0.14)
	OffsetY int `xml:"offsety,attr"`
	// Whether the objects are drawn according to the order of appearance ("index") or sorted by their y-coordinate ("topdown"). Defaults to "topdown".
	DrawOrder string `xml:"draworder,attr"`
	// Custom properties
	Properties Properties `xml:"properties>property"`
	// Group objects
	Objects []*Object `xml:"object"`
}

// Object is used to add custom information to your tile map, such as spawn points, warps, exits, etc.
type Object struct {
	// Unique ID of the object. Each object that is placed on a map gets a unique id. Even if an object was deleted, no object gets the same ID.
	// Can not be changed in Tiled Qt. (since Tiled 0.11)
	ID uint32 `xml:"id,attr"`
	// The name of the object. An arbitrary string.
	Name string `xml:"name,attr"`
	// The type of the object. An arbitrary string.
	Type string `xml:"type,attr"`
	// The x coordinate of the object in pixels.
	X int `xml:"x,attr"`
	// The y coordinate of the object in pixels.
	Y int `xml:"y,attr"`
	// The width of the object in pixels (defaults to 0).
	Width int `xml:"width,attr"`
	// The height of the object in pixels (defaults to 0).
	Height int `xml:"height,attr"`
	// The rotation of the object in degrees clockwise (defaults to 0). (since 0.10)
	Rotation int `xml:"rotation,attr"`
	// An reference to a tile (optional).
	GID uint32 `xml:"gid,attr"`
	// Whether the object is shown (1) or hidden (0). Defaults to 1. (since 0.9)
	Visible bool `xml:"visible,attr"`
	// Custom properties
	Properties Properties `xml:"properties>property"`
	// Used to mark an object as an ellipse. The existing x, y, width and height attributes are used to determine the size of the ellipse.
	Ellipses []*Ellipse `xml:"ellipse"`
	// Pollygons
	Polygons []*Polygon `xml:"polygon"`
	// Poly lines
	PolyLines []*PolyLine `xml:"polyline"`
}

// Ellipse is used to mark an object as an ellipse.
type Ellipse struct {
}

// Polygon object is made up of a space-delimited list of x,y coordinates. The origin for these coordinates is the location of the parent object.
// By default, the first point is created as 0,0 denoting that the point will originate exactly where the object is placed.
type Polygon struct {
	// A list of x,y coordinates in pixels.
	Points *Points `xml:"points,attr"`
}

// PolyLine follows the same placement definition as a polygon object.
type PolyLine struct {
	// A list of x,y coordinates in pixels.
	Points *Points `xml:"points,attr"`
}

// Point is point
type Point struct {
	// Point X
	X int
	// Point Y
	Y int
}

// Points is array of points
type Points []Point

// UnmarshalXML decodes a single XML element beginning with the given start element.
func (m *Points) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
	var item string
	if err := d.DecodeElement(&item, &start); err != nil {
		return err
	}

	if item == "" {
		return nil
	}

	ps := strings.Split(item, " ")

	points := make(Points, len(ps))

	for i, s := range ps {
		c := strings.Split(s, ",")
		if len(c) != 2 {
			return ErrInvalidObjectPoint
		}

		var x, y int
		var err error
		if x, err = strconv.Atoi(c[0]); err != nil {
			return err
		}
		if y, err = strconv.Atoi(c[1]); err != nil {
			return err
		}
		(*m)[i].X = x
		(*m)[i].Y = y
	}

	*m = (Points)(points)
	return nil
}