Help loading TGAs

i''d copy the code from lesson 32. This is the TGA cod ei always use flawlessly.

IT Administrator / Software Engineere
http://drdsoftware.cjb.net

This is a "copy" of that lesson, I''m just writing it so it only loads uncompressed tgas. it''s pretty much the same code, I just gave the variables different spelling to match my own code.

What kind of error does it give u ?

A memory allocation error ???

I get this as soon as it hits the Texture->Width line

EXENAME caused an invalid page fault in
module EXENAME.EXE at 0167:00401936.
Registers:
EAX=00000100 CS=0167 EIP=00401936 EFLGS=00010206
EBX=7803b6d0 SS=016f ESP=0073fba0 EBP=0073fc48
ECX=00000000 DS=016f ESI=00402020 FS=62ef
EDX=00000000 ES=016f EDI=0073fc44 GS=0000
Bytes at CS:EIP:
89 41 08 6a 00 68 dd 17 40 00 68 1f 18 40 00 6a
Stack dump:
0073fc88 0073fd00 0073fd04 80000000 00000000 80000000 3f800000 80000000 00000000 00000000 00000000 3f800000 00000000 00000000 00000000 00000000

Of course you get a runtime error Texture is a wild pointer. You have to initialize it to something (i.e. Texture = (TEXTURE *)malloc(sizeof(TEXTURE); or Texture = new TEXTURE; or Texture = &Texture2 where Texture2 comes from the outside world).

[edited by - Thunder_Hawk on January 3, 2003 5:07:11 PM]

You there is two types of TGA files, compressed and uncompressed. You should really support both. Not sure were I found the tutorial for loading compressed and uncompressed but I think it was here.

Why should I support both if I''m only going to be loading a few textures?

So what should my TEXTURE Texture line look like then? Texture = new(TEXTURE)?

Ok it works now. just going to post the code to make sure I did it right, and I''m freeing up the memory right..
Still not sure what Texture->TexId does since I never assigned anything to it..

bool TextureLoadTga(char *FileName,int TextureNumber)
{
    
    TGA_HEADER  TgaHeader;
    TGA         Tga;
    TEXTURE     *Texture = new TEXTURE;
    FILE        *File;
    char        Error[80];                  //To hold error messages
    int         cswap;                      //For swapping RGB values

    File=fopen(FileName,"rb");
    
    if(File==NULL)
    {
        sprintf(Error,"Missing File: %s.",FileName);
        MessageBox(NULL,Error,APPNAME,MB_OK);
        return false;        
    }

    //try to read in the header
    if(fread(&TgaHeader,sizeof(TGA_HEADER), 1,File)== 0)
    {
        fclose(File);
        return false;
    }

    //make sure it''s an uncompressed tga
    if(memcmp(uTGAcompare,&TgaHeader,sizeof(TgaHeader))!=0)
    {
        MessageBox(NULL,"TGA must be uncompressed.",APPNAME,MB_OK);
        fclose(File);
        return false;
    }
    
    //try to read next 6 bytes
    if(fread(Tga.Header,sizeof(Tga.Header),1,File)==0)
    {
        MessageBox(NULL,"Couldn''t read TGA.",APPNAME,MB_OK);
        fclose(File);
        return false;
    }
    
    Texture->Width=Tga.Header[1]*256+Tga.Header[0];
    Texture->Height=Tga.Header[3]*256+Tga.Header[2];
	Texture->BitsPerPixel=Tga.Header[4];
	Tga.Width=Texture->Width;
	Tga.Height=Texture->Height;
	Tga.BitsPerPixel=Texture->BitsPerPixel;
    sprintf(Error,"%d",(int)Tga.Width);
    MessageBox(NULL,ERROR,APPNAME,MB_OK);

    if((Texture->Width<=0)||(Texture->Height<=0)||((Texture->BitsPerPixel!=24)&&(Texture->BitsPerPixel!=32)))
    {
        sprintf(Error,"Error: %s is not a valid TGA image.",FileName);
        MessageBox(NULL,Error,APPNAME,MB_OK);
        fclose(File);
        return false;
    }

    //Set the pixel type
    if(Texture->BitsPerPixel==24)Texture->Type=GL_RGB;
    else Texture->Type=GL_RGBA;

    Tga.BytesPerPixel=(Tga.BitsPerPixel/8);
	Tga.ImageSize=(Tga.BytesPerPixel*Tga.Width*Tga.Height);
	Texture->ImageData=(GLubyte *)malloc(Tga.ImageSize);		    
    
    if(fread(Texture->ImageData,1,Tga.ImageSize,File)!=Tga.ImageSize)
    {
        sprintf(Error,"%s: Could not read image data!",FileName);
        MessageBox(NULL,Error,APPNAME,MB_OK);
        free(Texture->ImageData);
        fclose(File);
        return false;
    }
    
    //close the file
    fclose(File);
    
    //swap BGR into RGB
    for(cswap=0;cswap<(int)Tga.ImageSize;cswap+=Tga.BytesPerPixel)
    {
        Texture->ImageData[cswap] ^= Texture->ImageData[cswap+2] ^=
		Texture->ImageData[cswap] ^= Texture->ImageData[cswap+2];
    }

    MessageBox(NULL,"Checkpoint",APPNAME,MB_OK);

    //now build a texture using the ImageData
    //Or more likely.. crash my sys 
   	glGenTextures(1,&Texture->TexId);
	glBindTexture(GL_TEXTURE_2D,GameTextures[TextureNumber]);
	glTexImage2D(GL_TEXTURE_2D,0,3,Texture->Width,Texture->Height,0,GL_RGB,GL_UNSIGNED_BYTE,Texture->ImageData);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

    free(Texture->ImageData);
    delete(Texture);
    
    return true;
}
 

TexID is used when binding the texture. at least it is in all of the tutorials.

IT Administrator / Software Engineere
http://drdsoftware.cjb.net

glGenTextures(1,&Texture->TexId); << TexID being used

then when you bind the texture you use that.

Lukerd.

"To err is human, to really mess up requires a computer"

Ok, i fixed it to point to my GameTextures array. It''s working good now. Am I freeing up the memory for Texture right?