World: r3wp

data-type sensitive editor  but normally rebol is datatype unsensive 
 :)

so or we allways ue struct! to typify our variables (wich can't be 
reuse). In C if I make SDM2Header *a, *b; a content and b content 
(physical memory localtion) will not be the same

in rebol a: SMD2Header and b: SMD2Header will point to the same memory 
chunk ...

>> a: SMD2Header
>> b: SMD2Header
>> a/m_iMagicNum: 1234234
== 1234234
>> probe b/m_iMagicNum
1234234
== 1234234
>>

and that normal becaus in C to initialise data I will use a malloc 
call witch will attrubute to a and b on the same based type different 
memory location

in my example program that exploite the SMD2Header strucure we can 
see:

//-------------------------------------------------------------
//- Load
//- Loads an MD2 model from file
//-------------------------------------------------------------
bool CMd2::Load(const char * szFilename)
{
	unsigned char * ucpBuffer = 0;
	unsigned char * ucpPtr = 0;
	unsigned char * ucpTmpPtr = 0; 
	int iFileSize = 0;
	FILE * f;
	
	if(!(f = fopen(szFilename, "rb")))
	{
		APP->Log(COLOR_RED, "Could not open MD2 file %s", szFilename);
		return false;
	}

	//check file size and read it all into the buffer
	int iStart = ftell(f);
	fseek(f, 0, SEEK_END);
	int iEnd = ftell(f);
	fseek(f, 0, SEEK_SET);
	iFileSize = iEnd - iStart;

	//Allocate memory for whole file
	ucpBuffer = new unsigned char[iFileSize];
	ucpPtr = ucpBuffer;

	if(!ucpBuffer)
	{

  APP->Log(COLOR_RED, "Could not allocate memory for %s", szFilename);
		return false;
	}

	//Load file into buffer
	if(fread(ucpBuffer, 1, iFileSize, f) != (unsigned)iFileSize)
	{
		APP->Log(COLOR_RED, "Could not read from %s", szFilename);
		delete [] ucpBuffer;
		return false;
	}

	//close the file, we don't need it anymore
	fclose(f);

	//get the header
	memcpy(&m_Head, ucpPtr, sizeof(SMD2Header));

	//make sure it is a valid MD2 file before we get going
	if(m_Head.m_iMagicNum != 844121161 || m_Head.m_iVersion != 8)
	{
		APP->Log(COLOR_RED, "%s is not a valid MD2 file", szFilename);
		delete [] ucpBuffer;
		return false;
	}
	
	ucpTmpPtr = ucpPtr;
	ucpTmpPtr += m_Head.m_iOffsetFrames;

	//read the frames
	m_pFrames = new SMD2Frame[m_Head.m_iNumFrames];
	
	for(int i = 0; i < m_Head.m_iNumFrames; i++)
	{
		float fScale[3];
		float fTrans[3];
		m_pFrames[i].m_pVerts = new SMD2Vert[m_Head.m_iNumVertices];
		//expand the verices
		memcpy(fScale, ucpTmpPtr, 12);
		memcpy(fTrans, ucpTmpPtr + 12, 12);
		memcpy(m_pFrames[i].m_caName, ucpTmpPtr + 24, 16);
		ucpTmpPtr += 40;
		for(int j = 0; j < m_Head.m_iNumVertices; j++)
		{

   //swap y and z coords to convert to the proper orientation on screen

   m_pFrames[i].m_pVerts[j].m_fVert[0] = ucpTmpPtr[0] * fScale[0] + 
   fTrans[0];

   m_pFrames[i].m_pVerts[j].m_fVert[1] = ucpTmpPtr[2] * fScale[2] + 
   fTrans[2];

   m_pFrames[i].m_pVerts[j].m_fVert[2] = ucpTmpPtr[1] * fScale[1] + 
   fTrans[1];
			m_pFrames[i].m_pVerts[j].m_ucReserved = ucpTmpPtr[3];
			ucpTmpPtr += 4;
		}
		
	}

	//Read in the triangles
	ucpTmpPtr = ucpPtr;
	ucpTmpPtr += m_Head.m_iOffsetTriangles;
	m_pTriangles = new SMD2Tri[m_Head.m_iNumTriangles];
	memcpy(m_pTriangles, ucpTmpPtr, 12 * m_Head.m_iNumTriangles);

	//Read the U/V texture coords
	ucpTmpPtr = ucpPtr;
	ucpTmpPtr += m_Head.m_iOffsetTexCoords;
	m_pTexCoords = new SMD2TexCoord[m_Head.m_iNumTexCoords];
	
	short * sTexCoords = new short[m_Head.m_iNumTexCoords * 2];
	memcpy(sTexCoords, ucpTmpPtr, 4 * m_Head.m_iNumTexCoords);

	for(i = 0; i < m_Head.m_iNumTexCoords; i++)
	{

  m_pTexCoords[i].m_fTex[0] = (float)sTexCoords[2*i] / m_Head.m_iSkinWidthPx;

  m_pTexCoords[i].m_fTex[1] = (float)sTexCoords[2*i+1] / m_Head.m_iSkinHeightPx;
	}
	
	delete [] sTexCoords;

	//Read the skin filenames
	ucpTmpPtr = ucpPtr;
	ucpTmpPtr += m_Head.m_iOffsetSkins;
	m_pSkins = new SMD2Skin[m_Head.m_iNumSkins];
	
	//Load textures
	for(i = 0; i < m_Head.m_iNumSkins; i++)
	{
		memcpy(m_pSkins[i].m_caSkin, ucpTmpPtr, 64);
		//hack off the leading parts and just get the filename
		char * szEnd = strrchr(m_pSkins[i].m_caSkin, '/');
		
		if(szEnd)
		{
			szEnd++;
			strcpy(m_pSkins[i].m_caSkin, szEnd);
		}

		m_pSkins[i].m_Image.Load(m_pSkins[i].m_caSkin);
		ucpTmpPtr += 64;
	}
		
	delete [] ucpBuffer;
	return true;
}

countainer class :

class CMd2 : public CModel
{
public:

	//Set skin to one of the files specified in the md2 files itself
	void SetSkin(unsigned int uiSkin);
	//Set skin to a different image
	void SetSkin(CImage& skin);

	//Load the file
	bool Load(const char * szFilename);
	
	//Render file at the initial position
	void Render();
	//Render the file at a certain frame
	void Render(unsigned int uiFrame);


 //Animate the md2 model (start and end frames of 0 and 0 will loop 
 through the WHOLE model

 void Animate(float fSpeed = 30.0f, unsigned int uiStartFrame = 0, 
 unsigned int uiEndFrame = 0, bool bLoop = true);

	//constructors/destructo
	CMd2();
	CMd2(const char * szFile);
	~CMd2();

private:
	
	CTimer m_Timer;
	//file header information
	SMD2Header m_Head; 
	//Frame information
	SMD2Frame * m_pFrames;
	//Triangles
	SMD2Tri * m_pTriangles;
	//Texure coords
	SMD2TexCoord * m_pTexCoords;
	//Skin files
	SMD2Skin * m_pSkins;
	//Interpolated vertices
	SMD2Vert * m_pVerts;
	//Current skin
	unsigned int m_uiSkin;
	//Using a custom skin?
	bool m_bIsCustomSkin;
	//The custom skin
	CImage * m_pCustSkin;

};

you go too fast for me...;-)  I have to find some time this weekend 
to play with the first toys...

so you make a SDM2Header *m_Header; to declare your header type from 
structure SMD3Header, then you read the correct emont of data in 
the file  storing it to ucpPtr then you init m_Header it using  memcpy(&m_Head, 
ucpPtr, sizeof(SMD2Header));

if you want to load 3 MD2 files you need only to make other main 
pointer to the information you retrieve from the file

Shadwolf: "in rebol a: SMD2Header and b: SMD2Header will point to 
the same memory chunk ..."


yes, but you should do it as follows: a: make struct! SMD2Header 
b: make struct! SMD2Header

in rebol you will need to load 3 files to declare SDM2Header_f1 SMD2Header_f3 
and SMD2Header_f3 with for both the stricly identical content tso 
your recoding 3 times or X times the same thing ...

I'm not an expert on struct! far of that (wel in C yes but in REBOL 
no and I think it's because I'm not using load/library capability 
until now) but that's a good discution to point to difficulties on 
this kind of task and I hope help rebol Core to have a bettre handling 
of that

ladyslav on declaration statement REBOL need me to give him the datas 
I ust tryed what you just propose:

>> a: make struct! SMD2Header
** Script Error: Invalid argument: (missing value)
** Near: a: make struct! SMD2Header

a: make struct! SMD2Header none ; or [some values here]

if you supply none, you generate an "empty" struct

shadwolf: have you read this? http://www.rebol.com/docs/library.html

yes so I had to read the file first then make my variable content 
basing me on a precut of the rode datas from file to be allowed to 
fill my variable content on inititialisation

you can create an empty struct using NONE and fill it using the read 
data

yes I read it cyphre long time ago when it was recently published 
but one thing that's apear to me dangerous is for example use:

a-struct: make struct! [
        in-string [string!] "Input string"
        in-int [integer!] "Input integer"
    ] ["This is input" 42]

what is dangerous on that?

while in C my struct is struct a-struct { char in-string[25]; int 
in-int; }

how can I be certain using string! unlimited REBOL countainer to 
correctly feet with the char 25 strictly sized contained in C

no contained but countainer

the dangerous thing is that with rebal I can over pass easly the 
25 limitation and write every where in the countigous memeryy area 
;)

If I understand you well you have tu create string! of length 25 
in rebol for your purpose.

that's not a direct use for me I intent thru thi discution to enlight 
some problems that every one can infront using rebol external library 
capability

or reusing C/C++/VB binary struct based data type (like MD2 file 
format)

It is on you to not override the length of the string IMO You have 
to deal with this as you are working with static  memory so it is 
not a problem of Rebol itself. I think you ca easily write 'dangerous' 
code when dealing with DLL interfaces ;) Making error in this are 
usually ends up with crash (memory acces violation).

yes I know that ;)

maybe that IS a good point to make it harder to crash at the interface. 
 The toughest code to write is always the in-between stuff.

the main purpose I purchase is to enhance and simplify the rebol 
interaction with external lib and C/C++/VB structure binary file 
based

and that's why I can here to expose the difficulties I see on that 
issue and try with you to get infos or solutions to propose to Carl

so what is your solution? Do you know how to improve the interface?

It takes a guru level REBOLer who is also profishant in C to write 
an interface to a DLL, although there are becoming more and simple 
examples...but maybe shadwolf wants to make it a graphical process?

not that far .... lol

an ez-dll.r which takes in a .h and a .dll and lets you play, experiment, 
and try to controll any .dll might be a fun project.

Cyphre not at all and that's why I came here first to expose the 
problems then to seek solutions with you

I have written a research proposal grant for such a tool...

Interfacing with lower-level naguages (such as C) from Rebol looks 
a bit harder but when you gain more experience with it (=no crashes 
anymore ;)) you realize it works logically. I was also dissapointed 
for the firt time I tried to use some DLL. But now I'm more optimistic. 
The only think I miss is the callback handling.

grant proposal (ah, was writing backwards in French)

eFishAnt your right !!! in a C# ressource explorer motion (wich you 
can see in Shardevolp IDE for example ) could be an amazing thing 
and even more if the same code all you to do so on evry OS rebol 
stands in

Cyphre - you should let Carl know that you want callback handling. 
 I know several of us have wanted that.

Josh wrote a simple hello example .dll a while back, including how 
to write the .dll...I started to mention this to him, but we talk 
about lots of things...so not done yet...guess I can tell him to 
read this.

I mentioned this to Carl few times but you know... ;-)

ah, you must have made him think then of REBOL Platform ... ;-)