Starting out

[xArtx]

Hi Guys,
It’s taken me about a year to complete my Amiga hardware.
So I have CD32 + SX-1 with 6 Mb RAM total. The last thing I got was the keyboard.

I want suggestions for an easy way to get started with C,
and wanting to draw primitive shapes, text, and lines on a screen.
What compiler should I use? I don’t care about an IDE, but prefer easy setup.
Ok to type into an editor such as Ced, and compile from a shell.

Samples would also be handy to show what to do about different screen resolutions, how to know how big the window was made,etc.

I could be using an Amiga or WinUAE. Any tips?
Cheers, Art.

[Samurai_Crow]

Samples can be found on Aminet.org in dev/c directory.

[thomas]

What compiler should I use?

vbcc is great, but 6 MB RAM is a bit tight.

Perhaps Dice C is better for your machine. Installation instructions: http://eab.abime.net/showpost.php?p=874957&postcount=2

Originally Posted by Samurai_Crow

Samples can be found on Aminet.org in dev/c directory.

aminet.net, not .org

http://aminet.net/dev/c

[xArtx]

Yes I already figured out the first address is dead.
A lot of things I googled: CubicIDE, StormV4, etc. I cannot find free on the net.
I will try Dice C then, cheers

Thomas, I notice you made the tutorial, If I compile the test program successfully,
would it be too much to ask for you to do a source that:
Draws a line or some pixels and writes a Hello World on the same graphics screen?

[xArtx]

Stand back, I’m an Amiga programmer now

[thomas]

Originally Posted by xArtx

would it be too much to ask for you to do a source that:
Draws a line or some pixels and writes a Hello World on the same graphics screen?

See attachment.

To (re)build it, cd into either demo1 or demo2 directory and enter dmake.

[xArtx]

Thanks Thomas,
It takes burning a CD for me to get it to the Amiga hardware (I skipped UAE),
but my Mac can extract .lha, and I see the first example is a pong ball
and the variable size of a resizable window is accounted for.

Done for tonight, but will start again tomorrow

I have a 40Mb HDD with 1.4Mb free after the Dice C install.
...had to delete the previous owners game directory and some other stuff.
I’ll have a look for more room I can possible make.

Originally Posted by thomas

See attachment.

To (re)build it, cd into either demo1 or demo2 directory and enter dmake.

[thomas]

To save some space you can delete the directories

doc
editors
examples
l
libs
rexx

from Dice as well as all files in the main Dice directory.

The NDK_3.9 can be deleted entirely after you copied the includes and linker_libs to Dice. However, you might want to retain the autodocs.

[duga]

Good luck. What will you focus on; OS 3.1 or 3.9?

Trying to learn C for OS 4.1 here.

[xArtx]

Hi, It would be OS 3.1 for a CD32 yeah? CD32 is my only real hardware.
I have ideas rather than solid goals for end programs, but fairly proficient with C,
so hopefully will gain momentum with more understanding of the Amiga.

Originally Posted by duga

Good luck. What will you focus on; OS 3.1 or 3.9?

Trying to learn C for OS 4.1 here.

[xArtx]

Hi again Guys I have reached a problem.

I want to use the C sin() and cos() functions that are normally in math library.

I’ve tried including mathtrans.h and mathieeesingtrans.h, and if I call their respective
sine or cosine functions:

SPSin(theta);
IEEESPSin(theta);

The program compiles, but when run it crashes with error #8000000B,
which I Googled to mean the program requires a hardware floating point unit.

Is there a way to use sin/cos without the FPU hardware?
Cheers, Art.

[tolkien]

I don't know but <math.h> have sin() and cos()? Linked with -lm ofcourse.

[xArtx]

There is no math.h in the SDK. I was talking about a math.h I use on other platforms.

I was talking about this kind of thing.
Supposed to use FPU hardware if it exists, CPU otherwise.

struct Library *MathBase;
 
VOID main()
{
float f1;
long i1;
 
if (MathBase = OpenLibrary("mathffp.library", 0)) {
    i1 = SPFix(f1);     // copy float to integer long
    CloseLibrary(MathBase);
} else {
printf("Can't open mathffp.library\n");
}

Can a float be given a value when it is declared like this?

float pi = 3.14159;

or is it more complicated than that?

[tolkien]

But <math.h> is part of any C compiler no platform specific.

Yes, you declared a float in that form and the example seems ok. Perhaps you need to tweak some compiler option?

[thomas]

Originally Posted by xArtx

The program compiles, but when run it crashes with error #8000000B

You need an updated SetPatch: http://aminet.net/package/util/boot/SetPatch_43.6b

Actually the math#?.library's should hide the need for an FPU and switch to software floating point routines automatically. But for some reason the proper libs didn't make it into the A1200/CD32 ROM.

Originally Posted by xArtx

There is no math.h in the SDK.

math.h is part of the compiler's include files. It should be in DINCLUDE: along with stdio.h and the like.

You don't need the SDK to compile an ANSI C program.

[xArtx]

Oh ok.. I couldn’t find it in the NDK_3.9 directory, and then Googled how to use what was there.

I’m trying to rotate a point about an origin and this simple thing has turned into a monster using that mathtrans thing.

theta = rotation;
thetab = (3.141592 / 180) * theta;

    xx = 160;
    yy = 200;
    x = xx - 160;
    y = yy - 140;
    xnew = cos(thetab)*x - sin(thetab)*y;
    ynew = sin(thetab)*x + cos(thetab)*y;
    xnew = xnew + 160;
    ynew = ynew + 140;

[thomas]

There is an example which mixes math.h with AmigaOS functions: http://thomas-rapp.homepage.t-online...les/piechart.c

[xArtx]

Ok, thanks again
Will have to be a job for tomorrow. It’s past 3am here!
Just the SetPatch file requires burning another CD,
but I’ll try to put more on it this time, like as much of my own C code I can fit on it.

[xArtx]

Success!
The updated SetPatch file was required.
The same source I posted above crashes while compiling with my old version.
I wish I’d known that. Now the code I posted above compiles as it is written.
Though for the Amiga I’m probably going to want to pre-calculate this:

3.141592 / 180

and both of these since the result is used twice:

sin(thetab)
cos(thetab)

lol.

[tolkien]

For sure It's better to precalculate al sin() cos() you can. They are expensive CPU functions.