How are .dds files loaded?

Nickasaur · Aug 14, 2009

How are the texture .dds files loaded onto models? If anyone could go ahead and grab the code where it loads the dds files onto the models, PM me it. I just need to study how they are loaded in C++ so I can use it for my Java FlyFF.
Don't go all screaming at me, I know they are probably completely different, but I understand some C++ so I'd probably be able to convert it.
-Thanks.

spikensbror · Aug 15, 2009

I have no experience at all, but here's something i found.

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FrostElite · Aug 15, 2009

I can't speak for Java, but in C# with XNA you would define and load a DDS texture like
this.

PHP:

Texture2D.FromFile(graphics.GraphicsDevice, "Randomtexture.dds")

---------- Post added at 01:00 AM ---------- Previous post was at 12:58 AM ----------

Edit - after a bit of research I've discovered this

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I skimmed it and it seems like it loads DDSFiles and displays them to the screen.
Hope this is what you were looking for.

Duotone · Aug 16, 2009

Useing this in c++ opengl
Returns -1 if it couldnt load the file.
Load the whole file to a char array, and pass it to this function.

Code:

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glaux.h>
#include <ddraw.h>
#include "glext.h"

#define FOURCC_DXT1_REV  (MAKEFOURCC('1','T','X','D'))
#define FOURCC_DXT2_REV  (MAKEFOURCC('2','T','X','D'))
#define FOURCC_DXT3_REV  (MAKEFOURCC('3','T','X','D'))
#define FOURCC_DXT4_REV  (MAKEFOURCC('4','T','X','D'))
#define FOURCC_DXT5_REV  (MAKEFOURCC('5','T','X','D'))

GLuint loadCompressedTexture(const char *file)
{
	GLenum format=0;
    int nBlockSize=-1;

    GLuint tID = -1;
	char *puffer2=0, *p;
	bool compressed=false;
	int type;
	int a,r,g,b,c,d;

    if( (file[0]!='D')||(file[1]!='D')||(file[2]!='S') )
    {
        logger.log( "DDS header error\n");
        return -1;
    }

    DDSURFACEDESC2 &ddsd = *(DDSURFACEDESC2*)(&file[4]);
    int nHeight     = ddsd.dwHeight;
	int nWidth      = ddsd.dwWidth;
    int nNumMipMaps = ddsd.dwMipMapCount;

    switch( ddsd.ddpfPixelFormat.dwFourCC )
    {
        case FOURCC_DXT1:
		case FOURCC_DXT1_REV:
            format = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
			nBlockSize = 8;
			compressed=true;
            break;

        case FOURCC_DXT3:
		case FOURCC_DXT3_REV:
            format = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
			nBlockSize = 16;
			compressed=true;
            break;

        case FOURCC_DXT5:
		case FOURCC_DXT5_REV:
            format = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
			nBlockSize = 16;
			compressed=true;
            break;
        default:
			nNumMipMaps=1;
    }

	GLubyte *pixels=(GLubyte*)&file[sizeof(ddsd)+4];

	if(format==0)
	{
		switch(ddsd.ddpfPixelFormat.dwRGBBitCount)
		{
		case 32:
			if(!compressed)format=GL_RGBA;
			else format = GL_RGBA8;
			nBlockSize = 4;
			type=GL_UNSIGNED_BYTE;
			break;
		case 24:
			if(!compressed)format=GL_RGB;
			else format = GL_RGB8;
			type=GL_UNSIGNED_BYTE;
			nBlockSize = 3;
			break;
		case 16:
			if(compressed)
			{
				return -1;
			}
			else
			{
				int rmask=ddsd.ddpfPixelFormat.dwRBitMask;
				int gmask=ddsd.ddpfPixelFormat.dwGBitMask;
				int bmask=ddsd.ddpfPixelFormat.dwBBitMask;
				a=rmask & gmask & bmask;
				if(a<65535)
				{
					puffer2=new char[nWidth*nHeight*4];
					format=GL_RGBA;
					nBlockSize = 4;
					type=GL_UNSIGNED_BYTE;

				}else
				{
					puffer2=new char[nWidth*nHeight*3];
					format=GL_RGB;
					nBlockSize = 3;
					type=GL_UNSIGNED_BYTE;
				}
				d=0;
				int rdiv=0,rmult=0;
				for(a=rmask;(a&1)==0;a>>=1)rdiv++;
				for(;(a&128)==0;a<<=1)rmult++;
				int gdiv=0,gmult=0;
				for(a=gmask;(a&1)==0;a>>=1)gdiv++;
				for(;(a&128)==0;a<<=1)gmult++;
				int bdiv=0,bmult=0;
				for(a=bmask;(a&1)==0;a>>=1)bdiv++;
				for(;(a&128)==0;a<<=1)bmult++;
				int amask=~(rmask & gmask & bmask);

				for(a=0;a<(nWidth*nHeight*2);a+=2)
				{
					c=*(short*)&pixels[a];
					r=c&rmask;
					g=c&gmask;
					b=c&bmask;

					r>>=rdiv;
					g>>=gdiv;
					b>>=bdiv;

					r<<=rmult;
					g<<=gmult;
					b<<=bmult;
					if((nBlockSize==4)&&((c&amask)!=0))c=255;else c=0;
					puffer2[d]=r;
					puffer2[d+1]=g;
					puffer2[d+2]=b;
					if(nBlockSize==4)puffer2[d+3]=c;

					d+=nBlockSize;
				}
			}
			break;
		default:
			logger.log(" unknown format %d", ddsd.ddpfPixelFormat.dwRGBBitCount);
		}
	}


	if(nBlockSize==-1)
	{
		logger.log("error unknonw pixelformat %08x", format);
		return -1;
	}


    glGenTextures( 1, &tID );
    glBindTexture( GL_TEXTURE_2D, tID );

    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
	glTexParameteri( GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_FALSE );

	int nSize;
	int nOffset = 0;
	
	if(nNumMipMaps<1)nNumMipMaps=1;
	for( int i = 0; i < nNumMipMaps; ++i )
	{
		if( nWidth  == 0 ) nWidth  = 1;
		if( nHeight == 0 ) nHeight = 1;
		if(compressed)nSize = ((nWidth+3)/4) * ((nHeight+3)/4) * nBlockSize;
		else nSize=nWidth*nHeight*nBlockSize;

		if(!compressed)
		{
			p=(char*)pixels;
			if(puffer2!=0)p=puffer2;
			glTexImage2D( GL_TEXTURE_2D, 0, nBlockSize, nWidth, nHeight, 0, format, type, p );
		}
		else glCompressedTexImage2DARB( GL_TEXTURE_2D, i, format, nWidth, nHeight, 0, nSize, &pixels[nOffset] );
		nOffset += nSize;
		nWidth  = (nWidth  / 2);
		nHeight = (nHeight / 2);
	}
	
    delete[] puffer2;
    return tID;
}

Loading uncompressed files is like loading bmp files.
For compressed ones you can use glCompressedTexImage2DARB function.