PLOT and DRAWTO with CC65 in C? [solved]

[Wrathchild]

26 minutes ago, Pokeypy said:

I tried to understand your code

 

It's not my code in afraid, just an example I found of the use of the tgi calls

 

28 minutes ago, Pokeypy said:

As I don't have the limitations of classic computers

 

You need to consider the likes of Telengard where the 100x100x100 maze is just the property of a function

 

    for(outer=0; outer<4; outer++) {
        for(inner=0; inner<4; inner++) {
            map[outer][inner] = whats_at(x_pos+inner-1,y_pos+outer-1,z_pos);
        }
    }

 

map.c

[stepho]

14 hours ago, Pokeypy said:

That's really a cool piece of code! Seems to be the basis of "Bard's Tale", which is probably my favourite game of all time (it's on the Amiga).

So the last few days, I tried to understand your code. Actually, I did a rewrite in Python/Pygame, integrating other people's library code for maze generation.

My script works now, it has 35K (about 1000 lines of code); it's not Atari 8 bit programming though, so it would be a bit off-topic here. As I don't have the limitations of classic computers, I can have rather large mazes, like 100x100 for example, where you really get lost.

My questions about your C-version would be:

- ".Border" seems to be initialized with just a "|=". So that's "....Border = ....Border | RIGHT;". Doesn't that mean, that ".Border" is undefined in the first place?

- These macros like

#define GoodDir( Cell, Dir )   ((g.Maze[ (Cell) ].Border & (Dir)) == 0)

replace functions, right? How would they be written as functions? (As functions, I could understand that kind of code more easily.)

- What do ".Walls", ".Border", ".Path" actually mean? They're just integers. How do they describe the properties of a maze cell?

- Unfortunately, I also didn't fully understand your maze generating algorithm. But I see, what you were going for, for something like this (seems to be a general problem in computer science), so I used that Python library instead.

I know, you wrote that code 11 years ago and probably don't have the time to answer everything in detail.

But I thank you very much for it anyway. It's cool!

It's not my code either but I can answer some of your questions.

 

Most C compilers initialise variables to 0 (unless some other value is specifically given for a specific variable).
So all the borders are initialised to have no border walls and are later modified to have bit 0 and/or 1 turned on via |= RIGHT or |=BOTTOM.

 

Macro function can usually be converted to ordinary function in a mechanical fashion.

static int GoodDir( int Cell, int Dir )
{
    return (g.Maze[Cell].Border & Dir) == 0;
}

 

Called by 

bool flag;

flag = GoodDir( Cell, Dir );

[ilmenit]

This example code is a really good example of how not to write programs in CC65

While it's a proper C, the generated code will be crazy inefficient and huge on the 6502.

[sanny]

7 hours ago, stepho said:

Most C compilers initialise variables to 0 (unless some other value is specifically given for a specific variable)

 

Be careful. Local variables which aren't initialized have a random value.

(File-)Global variables which aren't initialized are defined to be 0 (by the C standard). I they aren't 0 in one compiler, it's a compiler bug.

[stepho]

15 hours ago, sanny said:

 

Be careful. Local variables which aren't initialized have a random value.

(File-)Global variables which aren't initialized are defined to be 0 (by the C standard). I they aren't 0 in one compiler, it's a compiler bug.

True, I should have said "global variables".