A Simutrans'object is composed of (most of the time) pictures for display and datas for technical datas of the object. The datas are just written in a simple text file (.txt) but saved with the extension .dat. Easy to do it : when saving your file, replace the .txt extension by a .dat extension. To open your .dat files you have to adjust your computer to open these files with the text editor (notepad with windows). This an example with windows :
Inside the text you can write parameters one after each other but you'd rather write them one below each other for a better aspect. You can put several objects in the .dat file if you separate them with dashes.
for example :
—
Parameters of the second object
Pictures have other constraints depending on the pakset you create for. The picture must be saved as 24 bits .png (Photofiltre save in 24 bits by default), makeobj can only read .png and if it's a 32 bits .png (with a transparency layer) you'll have a graphical glitch. The dimensions of your pictures must be multiples of the pakset's size. If it's pak128, pictures will 1024*256 or 768*512 for example. If you create for pak64 you'll have pictures of 128*64 or 192*384 for example, etc … If the size isn't right, makeobj will crash.
You have to know how the source pictures work.
The picture is cut in 128*128 pixels squares (so the picture must have dimensions multiple of 128). This is an example of a source picture part (here is the source picture of the AMT) :
Then you'll have to define the squares in the .dat file. Coordinates are used, the first for lines and the second for columns. See here in the same picture :
The .dat file parameters and the corresponding pictures can be different but can be also very repetitive if you often create the same type of objects, so I will give you graphical shapes and .dat shapes for you to make your files easier, objects will be described one by one.
A picture is defined in a .dat file as this :
example : imageUp[3]=AMT.3.3
the picture used for imageUp[3] is the square on the intersection of the fourth line and the fourth column of AMT.png.
Every number is integer. The text respects shift.
The offset allows you to move the picture in some situations. This technic must be used only in necessary situations, it musn't be used instead of the moving directly the graphics on the picture.
How to use the offset :
x is the number of pixels to the right and y is the number of pixels to the bottom.
In the example below, the picture is moved of 16 pixels to the top.
Since Simutrans 120, slopes can be of two different heights. Some paksets use full and half slopes, some other paksets use full and double slopes.
Pak128 use half slopes. In this pakset, most ways cannot be built on hard slopes, such as tracks and highways.
Objects which need icons have something like that on their graphical pattern:
Images of icons must contain only the 16 by 16 pixels square at top left of this image, everything else must be removed, otherwise there would be display errors in game.
The elements around the icon itself are specific to pak128, they are used in its icons.
On graphical patterns of objects needing a cursor, the tile used to place the cursor is higher than the bottom of the square which it is placed in. This is intended to compensate an offset downward applied by the game.
You will find example of source files for all kinds of objects in each pakset's repository.
Under windows, simple text editors such as notepad or notepad++ are used. You cannot use text processing programs like Word or Writer. It's accessible in the start menu\programs\accessories\notepad. The useful tools of notepad are the research tool and the replace tool that you find in the edition menu.
Be careful using the tool “replace” if you use the icon “replace all”, it can modify some text parts which aren't supposed to be.
Finally, to save a source file for Simutrans, replace the default extension ”.txt” by the extension ”.dat”.
Linux has many text editors. They often depend on the release, or on the installed desktop manager. The best thing to do is to see the documentation given with your text editor to know its keyboard shortcuts.
To save a source file for Simutrans, the process is the same as windows, you just have to use the extension ”.dat” for the file.
graphics of buildings : Buildings'graphics
waytype : Possible waytypes
engine_type : Energy of vehicles
freight / goods : Goods of pak128
smoke : Smokes of pak128
sound : Souds of pak128
system_type : Possible special parameters
climates : Climates in Simutrans