Normalizing the coordinates

[jklae]

Description
Currently, the drawing coordinates and the simulation coordinates are the same. It is not good because the smaller the grid scale, the larger the calculation error. Also, some coordinates are negative to center the grid position. These coordinates are very cumbersome in simulation calculations, especially when interpolating particle variables. Therefore, the simulation calculations will be more efficient by having the drawing coordinates and the simulation coordinates separately.

Todo

• Do not equate simulation coordinates with drawing coordinates.
• Normalize the simulation coordinates [0, N+2]. These coordinates make simulation calculations convenient.
• Remove variables like stride and offset. As long as the coordinates are normalized, these variables are not needed.
• Modify the interpolation function. In the interpolation function, the offset and stride of the particle are calculated. Since the coordinate system has changed, these must also be corrected.

Note
A method for compensating for the difference between the two coordinate systems is presented in jklae/DXViewer#25.
This issue is derived from #3.