Designing Games with Game Maker - YoYo Games

• When you use the 3D functionality, there are a number of other things that can no
longer be used.
o You cannot use background and foregrounds in your rooms anymore. (The
reason is that they are tiled to fill the image but with perspective projections
this no longer work correctly).
o You cannot use the mouse position anymore. The mouse will not be
transformed to the 3D coordinates. You can still get the position of the mouse
on the screen (in the view) but you will have to do calculation with this
yourself (or not use the mouse at all).
o You cannot use tiles anymore. Tiles will most likely no longer match up
correctly.
o Collision checking still uses the 2-d positions of the instances in the room. So
there is no collision detection in 3D. Sometimes you can still use this (if you
use the room as a representation of a flat world (e.g. for racing or FPS games)
but in other situations you have to do things yourself.
• All 3D functionality is through code. You must be rather fluent with the GML language.
Also you must really understand a lot about how Game Maker works otherwise you will
run into trouble.
• You must have some basic knowledge about 3D graphics. In particular I will use terms
like perspective projections, hidden surface removal, lighting, and fog, without much
explanation.
• There is no 3D modelling in Game Maker. Also I do not plan on adding support for
loading 3D models.
• You must work carefully to keep a reasonable speed. Also, things are not really
optimized for speed.
If this did not discourage you, read on.
Going to 3D mode
If you want to use 3D mode you first need to set Game Maker in 3D mode. You can later
switch back to 2D mode if you want. The following two functions exist for this.
d3d_start() Start using 3D mode. Returns whether successful.
d3d_end() Stop using 3D mode. Returns whether successful.
Note that all functions related to 3D mode start with d3d_.