How to get closer to transferring the game engine to another platform?

Question

I came across this problem several times earlier and wanted to hear what other experience and tips are. Suppose you have a working and stable, but relatively small game engine that works only on one platform, and you want to transfer it to another platform.

The first step is obvious: you take the code, link it to the platform libraries, not the old ones, make the necessary changes to the project settings or target buildings, and then click build. About five to twenty thousand errors appear. Of course, there are many duplicates, but the question immediately arises, what should be the next steps?

How do you approach the transfer of the game engine to another platform or some code on a platform that cannot be simply compiled on another platform due to inherent changes in the design of the system and API? How do you get through all these mistakes? How do you identify the parts you need to approach first?

In general: how do I approach porting existing source code?

I am looking for general recommendations on how to approach the source code port. Suppose the programming language and the compiler are the same on both platforms, so basically the API changes.

Answer 1

() , , - , . , , ( , , ), , , , , .

, :

void RenderBadGuy(int badGuyID)
{
    // Windows-specific bad-guy rendering code here
}

( "G_" )

void G_RenderBadGuy(int badGuyID)
{
    RenderBadGuy(badGuyID);
}

, , ( ).

, , RenderBadGuy, G_RenderBadGuy. , :

void G_RenderBadGuy(int badGuyID)
{
    // now we're rendering on a Mac
    RenderBadGuy_Mac(badGuyID);
}

.

, , ( , ), .

Java- , , , . (, ) , .