A sprite is an animated image that can be displayed on the screen or attached to an entity of the map. More precisely, a sprite displays images from an animation set with a current animation, a current direction and a current frame. Several sprites displayed at the same time can share the same animation set and have different states (i.e. different animations, directions and frames).

An animation set has at least two data files:

one or more PNG images that contains the images of the animation set,
a description file like sprites/XXX.dat, where XXX is a string that identifies the animation set. The description file contains the definition of each animation and direction of the animation set.

The sprite animation sets are represented as in Multimedia Fusion:

A sprite animation set is composed of one or several animations. For instance, the animation set of a basic enemy may have four animations: stopped, walking, hurt and shaking.
Each animation is composed of one or several directions, numbered from 0. Usual enemies have four directions.
Each direction is a sequence of frames, where a frame is a static image. The frames are numbered from 0. Once the animation is finished, it may loop by coming back to a specific frame (which may be other that the first one).

The description file (usually sprites/XXX.dat) contains those information. We describe here its syntax. It is a textual file that defines each animation. For each animation, we first have a line that give general information about the animation:

animation_name image_file nb_directions frame_delay loop_on_frame

animation_name is a name that identifies this animation.

image_file is the name of the PNG image that contains all frames of all directions of this animation. Its path is relative to the directory sprites. image_file may also be the keyword tileset, this means that the image file is the one of the current tileset. This can be used to make sprites that depend on the skin of the current map (e.g. animated doors). The PNG file is then tilesets/tilesetYYY_entities.png where YYY is the id of the current tileset.

nb_direction is the number of directions of this animation.

frame_delay is the delay in milliseconds between two frames of the animation, or 0 if there is only one frame and you want it to stay displayed.

loop_on_frame is the number of a frame where the animation will loop, or -1 to make the animation stop after the last frame. If the value is -1, the sprite will stop being displayed after the last frame, unless frame_delay is 0 (meaning that the only frame keeps being displayed).

After this first line, there is a line for each direction of the animation. For each directio, the line determines the location of the individual frames of this direction. In the PNG image, all frames of a direction are rectangles of the same size, placed in adjacent locations from left to right, possibly on several rows. Thus, instead of defining the frames one by one, we just specify the location of the first rectangle, the number of frames and the number of columns. A direction description has the following syntax:

x y frame_width frame_height origin_x origin_y nb_frames nb_columns

x and y are the coordinates of the top-left corner of area containg the frames. frame_width and frame_height are the size of each frame. Thus, the first frame is the rectangle of coordinates (x,y) and size (frame_width,frame_height). origin_x and origin_y are the coordinates of the origin point of the sprite relative to the top-left rectangle of a frame. nb_frames is the number of frames of this direction. Most of the time, this number is the same for all directions. nb_columns defines the number of columns of the grid containing the frames of this direction. The number of rows is deduced from nb_frames and nb_columns. The last row of the grid may be incomplete.

Here is an animation set description file example:

stopped hero/stopped.tunic.png 4 0 -1
0	0	24	24	12	21	1	1
24	0	24	24	12	21	1	1
72	0	24	24	12	21	1	1
96	0	24	24	12	21	1	1

walking hero/walking.tunic.png 4 100 0
0	0	24	32	12	29	8	8
0	32	24	32	12	29	8	8
0	96	24	32	12	29	8	8
0	128	24	32	12	29	8	8

sword hero/sword.tunic0.png 4 30 -1
0	0	32	32	16	29	12	12
0	32	32	32	16	29	12	12
0	64	32	32	16	29	12	12
0	96	32	32	16	29	12	12