HGE and Python (again)

[Cro]

Good day.

I've been trying to port HGE (http://hge.relishgames.com) to Python
for more than 4 months now...
HGE is a hardware accelerated 2D game engine.
It comes with the source and examples. In the folder "include", you
can find "hge.h", the file that i am talking about in all the post.

#
I tried to load the DLL functions with Python Ctypes like this :

But i get this error : "Procedure called with not enough arguments (4
bytes missing) or wrong calling convention".
The call should be done with hgeCreate(HGE_VERSION) and the constant
is defined as "#define HGE_VERSION 0x180"...
Number 0x180 means 384 in Python. I don't mean what it means in C.
So i am stuck.

I also tried to modify the "hge.h" file on line 408, and export the
rest of the classes...

__declspec (dllexport) hgeVertex;
__declspec (dllexport) hgeTriple;
__declspec (dllexport) hgeQuad;
__declspec (dllexport) hgeInputEvent;

But after compilation, i am not able to access them from Python
"ctypes". They seem to remain invisible. Perhaps i am not doing it
right?...

#
I tried Cython.
I tried to load "hge.h" in Cython and use the structures.
The first error i get is at line 173: "typedef bool (*hgeCallback)
();". I am not that good in C/C++ to understand what it means. So i
commented it...
The second big error is at line 408: "extern "C" { EXPORT HGE * CALL
hgeCreate(int ver); }". This should be the DLL export. I comented that
too...

I used this code in Cython, loading from "hge.h":

# file HGE.pyx
cdef extern from "windows.h":
   pass

cdef extern from "hge.h":
   pass

And i get this errors:

...\hge.h(215) : error C2061: syntax error : identifier 'hgeVertex'
...\hge.h(218) : error C2059: syntax error : '}'
...\hge.h(226) : error C2061: syntax error : identifier 'hgeVertex'
...\hge.h(229) : error C2059: syntax error : '}'
...\hge.h(274) : error C2061: syntax error : identifier 'HGE'
...\hge.h(274) : error C2059: syntax error : ';'
...\hge.h(275) : error C2449: found '{' at file scope (missing function
header?)
...\hge.h(407) : error C2059: syntax error : '}'

Then i tried to define hgeVertex in Cython like:

struct hgeVertex:
   float x, y      # screen position
   float z         # Z-buffer depth 0..1
   DWORD col      # color
   float tx, ty      # texture coordinates

But i get the exact same errors.
If i comment all the structures hgeVertex and Triple and Quad and the
HGE class, the Cython file compiles !... But it's not useful at all.
My Cython is okay, i compiled a few programs before, so that's not a
problem...

#
Then i tried Swig (and it worked with the examples )... But the
problems with "hge,h" seem to be somewhat similar.
I call swig like this : "swig -c++ -python hge.i"
And the file "hge.i" contains:

/* File : hge.i */
%module hge

%{
#include "hge.h"
%}

/* Let's just grab the original header file here */
%include "hge.h"

And the error i get after commenting the HGE callback and DLL export
is this : "hge.h(276): Error: Syntax error in input(3)." Line 276 is
exactly the first call of HGE class : "virtual void CALL Release() =
0;".

#
I tried Boost.Python (and it works with embedding and extending
examples), but i could't compile "hge.h" even after commenting the
structures and classes. I have to write some wrapper code in "hge.h"
and i am probably doing it completely wrong.

BOOST_PYTHON_MODULE(hge)
{
	using namespace boost::python;
	class_<hgeVertex> base("hgeVertex");
}

So i am stuck again...

I am not that good in neither C or Python.

Can anyone suggest any ideas? Please?
I really really really want to port HGE in Python. It's the greatest
game engine i have ever seen. The particle engine is EXCELLENT and i
need it.

Thank you in advance.

 

[Diez B. Roggisch]

Good day.

I've been trying to port HGE (http://hge.relishgames.com) to Python
for more than 4 months now...
HGE is a hardware accelerated 2D game engine.
It comes with the source and examples. In the folder "include", you
can find "hge.h", the file that i am talking about in all the post.

#
I tried to load the DLL functions with Python Ctypes like this :

But i get this error : "Procedure called with not enough arguments (4
bytes missing) or wrong calling convention".
The call should be done with hgeCreate(HGE_VERSION) and the constant
is defined as "#define HGE_VERSION 0x180"...
Number 0x180 means 384 in Python. I don't mean what it means in C.
So i am stuck.

You are aware that ctypes knows another call for windows dlls with
another calling convention?

http://docs.python.org/library/ctypes.html#loading-dynamic-link-libraries

Looking at the headers, I see

#define CALL __stdcall

So to me it looks as if you use the wrong DLL-loading mechanism.

Diez

 

[Cro]

Good day.

Thank you so much for your answer Diez!

I managed to call HGE dll the way you told:But it's not helpful. It would mean that i have to re-create all the
header files from "include" directory in python, and all helper
functions from the "libs" to be able to use hge in the same way as the
original.
So ctypes is not what i need. It's a big step!

I also tried swig, a lot.
A lot, a lot, a lot of examples. Hacking examples and stuff.
And i managed to compile "hge.h" header and call the structs and HGE
main class. I don't seem to be able to acces the "enums", but that's
not a big problem.
How i did that, if anyone wants to know: There are 4 files.
- There is "example.cxx", that includes "hge.h" in the proper C++ way
and defines a HGE* hge=0 just like in the tutorials.
- Then is "hge.h", the original file, with ONE line commented: line
408 with the DLL EXPORT. Ah, and one more thing. I had to delete ALL
"CALL" keywords from HGE class, because if one CALL appears, the swig
compiler flags the line as error. So, for now, no stdcall.
- Then is "example.i", with "#include "hge.h"" and "%include "hge.h"".
Simple as that.
- And then, there is setup.py. "example_module = Extension('_example',
sources=['example_wrap.cxx', 'example.cxx'],)"
That's it. I compile it all like this:

swig -c++ -python example.i
setup build_ext --inplace

So it's a huge step for me. The compiler i have in my system is
mingw-3.4.5. I don't know if it's good for this. Maybe i should try a
MS compiler instead?

Next things i want to do:
- try to compile the project with a MS compiles. Visual studio 7.1 or
somethin.
- learn if i can do stdcalls from swig !!! This is the most important.
- try to compile one normal hge tutorial WITHOUT including "hge.lib"
and "hgehelp.lib". All functions defined there can be included just
like normal headers, the source is there and i compiled the libs
myself. I need this step because i don't think i can include lib files
in a swig project.
- try to do all i did in swig, with Cython. It's pretty easy to use
and faster from what i know.

So i must learn to to stdcalls from swig.
Can anyone suggest how to do that?

I mean, i have lines like:
virtual void CALL Release(); // in HGE class.
And:
void CALL HGE_Impl::Release()
{
//... // In the "c" file.
}
, where CALL is defined as "#define CALL __stdcall".
I simply can't make this kind of classes so work in swig.

Thank you very much.