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OpenGL c++ texture class - Mine contribution to the community.

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Here comes mine contribution to the forum. Since I started to post threads here, I killed a bunch of doubts, and I'm very grateful. So, I remember a thing. We have allways people around searching for a loader of some type of image(file format), but allways get a library that do that. Well, not allways people want a library for some reason, so I get some ideas from internet and maked some adaptations to my needs. Conclusion: I writed a c++ class that load image from disk, and generate the openGL texture for you. The class supports .bmp, .png, .jpg, .tga, .pcx, anf tif. The only missing is .dds from directx. I think is support enough to the class :) The only requisites to the png, jpg, and tif, is that you will need the respective libraries to load that complex files. So you'll need libpng, libjpg, and libtiff to work with these. Ah! And if you use this class, you don't need to send me a e-mail, just post here that you are using this class. I want a feedback ;) If anyone want help to implement this source code, tell me. Some adjustments can be needed. The licence is GPL. And here comes the code: HEADER .hpp
/*
The Open Engine
Copyright (C) 2006 Johnny Birnfeld  https://sourceforge.net/projects/theopenengine

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

*/


#ifndef TOE_TEXTURE_H
#define TOE_TEXTURE_H

#include <string>
using namespace std;

class TOETexture{
	string _fileName;
	int _w;
	int _h;
	short int _bpp;
	unsigned int _id;
	unsigned char *_data;
	unsigned long _dataSize;
	
	float _OGLfilter;
	
	int readBMP( const char* );
	int readJPG( const char* );
	int readPNG( const char* );
	int readTIF( const char* );
	int readTGA( const char* );
	int readPCX( const char* );
	int readDDS( const char* );
	int generateTexture();
	void* combine( void*, size_t, void*, size_t );
	int tgaLoadRawData( unsigned char* );
	int tgaLoadRLEData( unsigned char* );
	void tgaBGRtoRGB();
	void flip();
	public:
		TOETexture();
		int load( string );
		int load( string, float );
		string fileName();
		unsigned int w();unsigned int h();
		unsigned int bpp();
		unsigned int id();
};

#endif


BODY .cpp
/*
The Open Engine
Copyright (C) 2006 Johnny Birnfeld  https://sourceforge.net/projects/theopenengine

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

*/


#include "TOETexture.hpp"
#include <iostream>
#include <fstream>
#include <GL/glu.h>

extern "C" {
	#include <jpeglib.h>
	#include <jerror.h>
}
#include <png.h>
#include <tiffio.h>


int TOETexture::readBMP( const char *filename ){
	unsigned short int bfType;
	long int bfOffBits;
	short int biPlanes;
	
	ifstream ifile(filename);
	if ( !ifile.good() )
		return 1; //File not found or corrupted.
	ifile.read( (char*)&bfType, sizeof(short int) );
	if (bfType != 19778){
		return 2; //Not a Bitmap-File
	}
	
	ifile.seekg(8, ios::cur); //skip file size and reserved fields of bitmap file header
	ifile.read( (char*)&bfOffBits, sizeof(long int) ); //get the position of the actual bitmap data
	ifile.seekg(4, ios::cur); //skip size of bitmap info header
	ifile.read( (char*)&this->_w, sizeof(int) ); //get the width of the bitmap
	ifile.read( (char*)&this->_h, sizeof(int) ); //get the heigth of the bitmap
	ifile.read( (char*)&biPlanes, sizeof(short int) ); //get the number of planes (must be set to 1)
	if (biPlanes != 1){
		return 3; //number of Planes not 1!
	}
	ifile.read( (char*)&this->_bpp, sizeof(short int) ); //get the number of bits per pixel
	if (this->_bpp != 24){
		return 4; //Bits per Pixel not 24!
	}
	
	_dataSize = this->_w * this->_h * 3; //calculate the size of the image in bytes
	_data = new unsigned char[_dataSize];
	
	ifile.seekg(bfOffBits, ios::beg); //seek to the actual data
	ifile.read( (char*)_data, _dataSize ); //read data
	
	//swap red and blue (bgr -> rgb)
	unsigned char temp;
	for ( unsigned int i = 0; i < _dataSize; i += 3 ){
		temp = _data[i];
		_data[i] = _data[i + 2];
		_data[i + 2] = temp;
	}
	
	ifile.close();
	
	this->_fileName = filename;
	
	return 0;
}

int TOETexture::readJPG( const char* filename ){
	
	FILE *file;
	struct jpeg_decompress_struct cinfo;
	struct jpeg_error_mgr jerr;
	volatile JSAMPROW row = 0;
	JSAMPROW rowptr[1];
	uint i,j,nrows;
	
	cinfo.err = jpeg_std_error(&jerr);
	jpeg_create_decompress(&cinfo);

	/* make sure the file is there and open it read-only (binary) */
	if ((file = fopen(filename, "rb")) == NULL){
		return 1; //File not found.
	}
	jpeg_stdio_src(&cinfo, file);
	jpeg_read_header(&cinfo, true);
	jpeg_start_decompress(&cinfo);
	
	this->_w = cinfo.output_width;
	this->_h = cinfo.output_height;
	//printf("Colorspace %d\n",cinfo.jpeg_color_space);
	this->_bpp = cinfo.jpeg_color_space*8; //JPEG images do not handle alpha channel.
	
	row = (JSAMPROW)calloc(1,cinfo.image_width * cinfo.output_components
			* sizeof(JSAMPLE));
	
	_dataSize = cinfo.image_width * cinfo.image_height * cinfo.output_components * sizeof(JSAMPLE);
	_data = (unsigned char*)malloc(_dataSize);
	rowptr[0] = row;
	
	for ( i = 0; i < cinfo.output_height; i++ ) {
		nrows = jpeg_read_scanlines(&cinfo, rowptr, 1);
		if (nrows != 1) {
			fprintf(stderr, "jpeg_read_scanlines"
					" returns %u, expected 1\n", nrows);
			return 5;
		}
		
		for ( j = 0; j < cinfo.output_width*cinfo.output_components; j++ )
			_data[(cinfo.output_height-1-i)*cinfo.output_width*cinfo.output_components+j] = row[j];
	
	}
	
	jpeg_finish_decompress(&cinfo);
	jpeg_destroy_decompress(&cinfo);
	free(row);
	
	this->_fileName = filename;
	
	return 0;
}

int TOETexture::readPNG( const char* filename ){
	unsigned int y;
	
	png_structp png_ptr;
	png_infop info_ptr;
	int number_of_passes;
	png_bytep * row_pointers;
	
	char header[8];	// 8 is the maximum size that can be checked
	
	/* open file and test for it being a png */
	FILE *fp = fopen(filename, "rb");
	if (!fp)
		return 1; //File not found
	fread(header, 1, 8, fp);
	if (png_sig_cmp((png_byte*)header, 0, 8))
		return 2; //Not a valid file
	
	/* initialize stuff */
	png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
	
	if (!png_ptr)
		return -1; //png_create_read_struct failed
	
	info_ptr = png_create_info_struct(png_ptr);
	if (!info_ptr)
		return -1; //png_create_info_struct failed
	
	if (setjmp(png_jmpbuf(png_ptr)))
		return -1; //Error during init_io
	
	png_init_io(png_ptr, fp);
	png_set_sig_bytes(png_ptr, 8);
	
	png_read_info(png_ptr, info_ptr);
	
	number_of_passes = png_set_interlace_handling(png_ptr);
	png_read_update_info(png_ptr, info_ptr);
	
	/* read file */
	if (setjmp(png_jmpbuf(png_ptr)))
		return -1; //Error during read_image
	
	row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * info_ptr->height);
	for ( y=0; y<info_ptr->height; y++ )
		row_pointers[y] = (png_byte*) malloc(info_ptr->rowbytes);
	
	png_read_image(png_ptr, row_pointers);
	
	
	
	this->_w = info_ptr->width;
	this->_h = info_ptr->height;
	this->_bpp = info_ptr->bit_depth;
	if ( info_ptr->color_type == PNG_COLOR_TYPE_RGBA ){
		this->_bpp *= 4;
	}else{
		if ( info_ptr->color_type == PNG_COLOR_TYPE_RGB ){
			this->_bpp *= 3;
		}else{
			std::cout << "Undefined color type for the png file." << std::endl;
		}
	}
	_dataSize = this->_h * info_ptr->rowbytes;
	_data = new unsigned char[_dataSize];
	
	int tszdata=0;
	for ( int c=0; c<this->_h; c++ ){
		_data = (unsigned char*)combine( _data, tszdata, row_pointers[c], info_ptr->rowbytes );
		tszdata += info_ptr->rowbytes;
	}
	
	this->_fileName = filename;
	
	
	
	
	/* finish decompression and release memory */
	png_read_end (png_ptr, NULL);
	png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
	/* we don't need row pointers anymore */
	free (row_pointers);
	
	fclose(fp);
	//Done reading .png file
	
	return 0;
}

int TOETexture::readTIF( const char *filename ){
	TIFFRGBAImage img;
	uint32 *raster;
	size_t npixels;
	
	TIFF *tif;
	char emsg[1024];
	tif = TIFFOpen(filename, "r");
	if (tif == NULL) {
		fprintf(stderr, "Problem loading %s\n", filename);
		return 1;
	}
	if ( TIFFRGBAImageBegin( &img, tif, 0, emsg ) ){
		npixels = img.width * img.height;
		raster = (uint32 *) _TIFFmalloc(npixels * /*img.samplesperpixel*/sizeof(uint32));
		if (raster != NULL) {
			if (TIFFRGBAImageGet(&img, raster, img.width, img.height) == 0) {
				TIFFError(filename, emsg);
				return 2;
			}
		}
		TIFFRGBAImageEnd(&img);
	}else{
		TIFFError(filename, emsg);
		return -1;
	}
	
	this->_w = img.width;
	this->_h = img.height;
	this->_bpp = 32/*img.bitspersample * img.samplesperpixel*/;
	_dataSize = this->_w * this->_h * this->_bpp/8;
	_data = new unsigned char[_dataSize];
	memcpy( _data, raster, _dataSize );
	this->_fileName = filename;
	
	
	TIFFClose(tif);
	return 0;
}

int TOETexture::readTGA( const char *filename ){
	
	ifstream ifile;
	unsigned long fileSize;
	unsigned char *pData;
	char bEnc;
	
	ifile.open( filename,ios::binary );
	if(ifile==NULL)
		return 1;
	
	// Get file size
	ifile.seekg(0,ios_base::end);
	fileSize=ifile.tellg();
	ifile.seekg(0,ios_base::beg);
	
	pData = new unsigned char[fileSize];
	if(pData==NULL){
		ifile.close();
		return -1;
	}
	
	// Read the file into memory
	ifile.read((char*)pData,fileSize);
	ifile.close();
	
	
	//Read Header
	short ColMapStart,ColMapLen;
	short x1,y1,x2,y2;
	
	if( pData[1] > 1 )    // 0 (RGB) and 1 (Indexed) are the only types we know about
		return 2; //Not a TGA file, or not supported format.
	
	bEnc = pData[2];     // Encoding flag  1 = Raw indexed image
                      //                2 = Raw RGB
                      //                3 = Raw greyscale
                      //                9 = RLE indexed
                      //               10 = RLE RGB
                      //               11 = RLE greyscale
                      //               32 & 33 Other compression, indexed
	
	if( bEnc > 11 or bEnc == 1 or bEnc == 9 ) // We don't want 32 or 33. And engine does not read indexed images too.
		return 2;
	
	
	// Get palette info
	memcpy(&ColMapStart,&pData[3],2);
	memcpy(&ColMapLen,&pData[5],2);
	
	// Reject indexed images if not a VGA palette (256 entries with 24 bits per entry)
	if(pData[1]==1) // Indexed
	{
		if(ColMapStart!=0 || ColMapLen!=256 || pData[7]!=24)
			return 2;
	}
	
	// Get image window and produce width & height values
	memcpy(&x1,&pData[8],2);
	memcpy(&y1,&pData[10],2);
	memcpy(&x2,&pData[12],2);
	memcpy(&y2,&pData[14],2);
	
	this->_w = (x2-x1);
	this->_h = (y2-y1);
	
	if(this->_w<1 || this->_h<1)
		return 2;
	
	// Bits per Pixel
	this->_bpp = pData[16];
	
	// Check flip / interleave byte
	if(pData[17]>32) // Interleaved data
		return 2;
	
	// Calculate image size
	this->_dataSize=(this->_w * this->_h * (this->_bpp/8));
	//Read Header
	
	
	switch(bEnc)
	{
		case 2: // Raw RGB
		{
			// Check filesize against header values
			if((this->_dataSize+18+pData[0])>fileSize)
				return 2;
			
			// Double check image type field
			if(pData[1]!=0)
				return 2;
			
			// Load image data
			if( tgaLoadRawData( pData )!=0 )
				return -1;
			
			tgaBGRtoRGB(); // Convert to RGB
			break;
		}
		
		case 10: // RLE RGB
		{
			// Double check image type field
			if( pData[1] != 0 )
				return 2;
			
			// Load image data
			if( tgaLoadRLEData( pData ) != 0 )
				return -1;
			
			tgaBGRtoRGB(); // Convert to RGB
			break;
		}
		
		default:
			return 2;
	}
	
	// Check flip bit
	//if((pData[17] & 0x20)==0){
	//	flip();
	//}
	
	// Release file memory
	delete [] pData;
	pData = NULL;
	
	this->_fileName = filename;
	
	return 0;
}

int TOETexture::readPCX( const char *filename ){
	
	struct PCXheader {
		unsigned char Manufacturer;
		unsigned char Version;
		unsigned char Encoding;
		unsigned char BitsPerPixel;
		short int Xmin, Ymin, Xmax, Ymax;
		short int HDpi, VDpi;
		unsigned char Colormap[48];
		unsigned char Reserved;
		unsigned char NPlanes;
		short int BytesPerLine;
		short int PaletteInfo;
		short int HscreenSize;
		short int VscreenSize;
		unsigned char Filler[54];
	};
	
	struct PCXheader pcxh;
	int bpl;
	unsigned char *row, *buf = NULL;
	
	ifstream ifile(filename);
	if ( !ifile.good() ){
		return 1;
	}
	
	ifile.read( (char*)&pcxh, sizeof(pcxh) );
	
	this->_w = (pcxh.Xmax - pcxh.Xmin) + 1;
	this->_h = (pcxh.Ymax - pcxh.Ymin) + 1;
	this->_bpp = pcxh.BitsPerPixel * pcxh.NPlanes;
	if ( this->_bpp != 24 ){
		ifile.close();
		return 2;
	}
	
	this->_dataSize = this->_w*this->_h*(this->_bpp/8);
	this->_data = new unsigned char[this->_dataSize];
	
	
	bpl = pcxh.NPlanes * pcxh.BytesPerLine;
	buf = new unsigned char[bpl];
	row = this->_data;
	for ( int y=0; y<this->_h; ++y ) {
		/* decode a scan line to a temporary buffer first */
		int i, count = 0;
		unsigned char ch;
		unsigned char *dst = buf;
		for(i = 0; i < bpl; i++) {
			if(!count) {
				ifile.read( (char*)&ch, 1 );
				if( (ch & 0xc0) == 0xc0) {
					count = ch & 0x3f;
					ifile.read( (char*)&ch, 1 );
				} else
					count = 1;
			}
			dst[i] = ch;
			count--;
		}
		
		/* de-interlace planes */
		unsigned char *src = buf;
		int plane;
		for(plane = 0; plane < pcxh.NPlanes; plane++){
			int x;
			dst = row + plane;
			for(x = 0; x < this->_w; x++) {
				*dst = *src++;
				dst += pcxh.NPlanes;
			}
		}
		row += this->_dataSize/this->_h;
	}
	delete[] buf;
	ifile.close();
	
	flip();
	
	this->_fileName = filename;
	
	return 0;
}

int TOETexture::readDDS( const char *filename ){
	return 1;
}

int TOETexture::generateTexture(){
	
	glGenTextures( 1, &this->_id );
	glBindTexture( GL_TEXTURE_2D, this->_id );
	
	if ( this->_OGLfilter == GL_NEAREST ){ //NORMAL
		if ( this->_bpp != 32 ){ //imagem não tem canal alfa
			glTexImage2D( GL_TEXTURE_2D, 0, 3,
					this->_w, this->_h,
					0, GL_RGB, GL_UNSIGNED_BYTE,
					_data );
		}else{
			glTexImage2D( GL_TEXTURE_2D, 0, 4,
					this->_w, this->_h,
					0, GL_RGBA, GL_UNSIGNED_BYTE,
					_data );
		}
	}else{ //MIPMAP
		if ( this->_bpp != 32 ){ //imagem não tem canal alfa
			gluBuild2DMipmaps(GL_TEXTURE_2D, 3,
					this->_w, this->_h,
					GL_RGB, GL_UNSIGNED_BYTE,
					_data);
		}else{
			gluBuild2DMipmaps(GL_TEXTURE_2D, 4,
					this->_w, this->_h,
					GL_RGBA, GL_UNSIGNED_BYTE,
					_data);
		}
		
	}
	
	if ( this->_OGLfilter == GL_NEAREST ){
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	}else{
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	}
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, this->_OGLfilter);
	
	
	return 0;
}

void* TOETexture::combine (void *o1, size_t s1, void *o2, size_t s2){
	void *result = malloc(s1 + s2);
	if (result != NULL)
		mempcpy(mempcpy(result, o2, s2), o1, s1);
	return result;
}

int TOETexture::tgaLoadRawData( unsigned char* ppData ) // Load uncompressed image data
{
	short iOffset;
	
	this->_data=new unsigned char[this->_dataSize];
	
	if(this->_data==NULL)
		return -1;
	
	iOffset = ppData[0]+18; // Add header to ident field size
	
	if(ppData[1]==1) // Indexed images
		iOffset+=768;  // Add palette offset
	
	memcpy(this->_data,&ppData[iOffset],this->_dataSize);
	
	return 0;
}

int TOETexture::tgaLoadRLEData( unsigned char* ppData ) // Load RLE compressed image data
{
	short iOffset,iPixelSize;
	unsigned char *pCur;
	unsigned long Index=0;
	unsigned char bLength,bLoop;
	
	// Calculate offset to image data
	iOffset=ppData[0]+18;
	
	// Add palette offset for indexed images
	if(ppData[1]==1)
		iOffset+=768; 
	
	// Get pixel size in bytes
	iPixelSize=this->_bpp/8;
	
	// Set our pointer to the beginning of the image data
	pCur=&ppData[iOffset];
 
	// Allocate space for the image data
	this->_data=new unsigned char[this->_dataSize];
 
	if(this->_data==NULL)
		return -1;
 
	// Decode
	while(Index<this->_dataSize) 
	{
		if(*pCur & 0x80) // Run length chunk (High bit = 1)
		{
			bLength=*pCur-127; // Get run length
			pCur++;            // Move to pixel data  
			
			// Repeat the next pixel bLength times
			for(bLoop=0;bLoop!=bLength;++bLoop,Index+=iPixelSize)
				memcpy(&this->_data[Index],pCur,iPixelSize);
			
			pCur+=iPixelSize; // Move to the next descriptor chunk
		}
		else // Raw chunk
		{
			bLength=*pCur+1; // Get run length
			pCur++;          // Move to pixel data
			
			// Write the next bLength pixels directly
			for(bLoop=0;bLoop!=bLength;++bLoop,Index+=iPixelSize,pCur+=iPixelSize)
				memcpy(&this->_data[Index],pCur,iPixelSize);
		}
	}
 
	return 0;
}

void TOETexture::tgaBGRtoRGB() // Convert BGR to RGB (or back again)
{
	unsigned long Index,nPixels;
	unsigned char *bCur;
	unsigned char bTemp;
	short iPixelSize;
	
	// Set ptr to start of image
	bCur = this->_data;
	
	// Calc number of pixels
	nPixels = this->_w*this->_h;
	
	// Get pixel size in bytes
	iPixelSize = this->_bpp/8;
	
	for(Index=0;Index!=nPixels;Index++)  // For each pixel
	{
		bTemp=*bCur;      // Get Blue value
		*bCur=*(bCur+2);  // Swap red value into first position
		*(bCur+2)=bTemp;  // Write back blue to last position
		
		bCur+=iPixelSize; // Jump to next pixel
	}
	
}

void TOETexture::flip( ) // Flips the image vertically (Why store images upside down?)
{
	unsigned char bTemp;
	unsigned char *pLine1, *pLine2;
	int iLineLen,iIndex;
 
	iLineLen=this->_w*(this->_bpp/8);
	pLine1=this->_data;
	pLine2=&this->_data[iLineLen * (this->_h - 1)];
 
	for( ;pLine1<pLine2;pLine2-=(iLineLen*2))
	{
		for(iIndex=0;iIndex!=iLineLen;pLine1++,pLine2++,iIndex++)
		{
			bTemp=*pLine1;
			*pLine1=*pLine2;
			*pLine2=bTemp;
		}
	}
 
}







///public methods
TOETexture::TOETexture(){
	this->_OGLfilter = GL_LINEAR_MIPMAP_LINEAR; //Default value to the texture filter(Trilinear).
}

int TOETexture::load( string filename ){
	return this->load( filename, this->_OGLfilter );
}

int TOETexture::load( string filename, float filterToUse ){
	this->_OGLfilter = filterToUse;
	int returnValue = 0;
	string ext = filename.substr( filename.length()-3, filename.length()-1 );
	string extl = filename.substr( filename.length()-4, filename.length()-1 );
	
	if ( ext == "bmp" ){
		returnValue = readBMP( filename.c_str() );
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	if ( ext == "jpg" or extl == "jpeg" ){
		returnValue = readJPG( filename.c_str() );
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	if ( ext == "png" ){
		returnValue = readPNG( filename.c_str() );
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	if ( ext == "tif" or extl == "tiff" ){
		returnValue = readTIF( filename.c_str() );
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	if ( ext == "tga" ){
		returnValue = readTGA( filename.c_str() );
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	
	if ( ext == "pcx" ){
		returnValue = readPCX( filename.c_str() );
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	if ( ext == "dds" ){
		returnValue = readDDS( filename.c_str() );
		cout << "INFO: " << this->_w << endl;
		cout << "INFO: " << this->_h << endl;
		cout << "INFO: " << this->_bpp << endl;
		cout << "INFO: " << this->_fileName << endl;
		if ( returnValue == 0 ){
			returnValue = generateTexture();
		}
	}
	
	switch( returnValue ){
		case -1:
			cout << "Error loading " << filename << ". Internal error reading image." << endl;
			break;
		case 1:
			cout << "Error loading " << filename << ". File not found." << endl;
			break;
		case 2:
			cout << "Error loading " << filename << ". Unexpected file format. Wrong extension?" << endl;
			break;
		case 3:
			cout << "Error loading " << filename << ". Number of Planes not 1." << endl;
			break;
		case 4:
			cout << "Error loading " << filename << ". Unexpected bits per pixel." << endl;
			break;
		case 5:
			cout << "Error loading " << filename << ". Unexpected number of rows." << endl;
			break;
		case 50:
			cout << "Error loading " << filename << ". Could not generate texture." << endl;
			break;
	}
	
	return returnValue;
}

string TOETexture::fileName(){
	return this->_fileName;
}

unsigned int TOETexture::w(){
	return this->_w;
}

unsigned int TOETexture::h(){
	return this->_h;
}

unsigned int TOETexture::bpp(){
	return this->_bpp;
}

unsigned int TOETexture::id(){
	return this->_id;
}



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Quote:

The licence is GPL.

:(

But anyway, here are my comments.


  • How about some documentation?

  • Don't put "using namespace std;" in header files! You've polluted the global namespace and defeated the entire purpose of namespaces.

  • What's with TOETexture? Just call it Texture and place it in a namespace. Prefixing class names is generally sort of useless; namespaces do a much better job.

  • You #include <string> but you use C strings for all your function parameters. Why?

  • Your public interface has very poor naming conventions. "w()" and "h()" and "bpp()" are terrible names.

  • You don't have a way of selectively disabling the loads I don't want to use. For example, lets say I only want to use the PNG functionality. You should have preprocessor switches I can set to skip the TIFF, et cetera, functionality so I don't have to link with all these extra libraries that I will never use.

  • Why is _OGLfilter a float?

  • You handle errors by returning magic numbers. You should really throw exceptions in many of these cases, or at the very least return enumeration values. When I recieve a return code of 4 from readBMP(), I have no idea what it means. This is not useful at all.

  • Your bitmap handling is pretty restrictive, isn't it? You only support certain bitmap color formats and such. Other types, like TGA, seem equally artificially restricted.

  • You mix C style IO (the JPEG loader) and C++ style IO (the bitmap loader). This has rather negative implications... the overall lack of consistency in the style of the code and the comments suggests this code is based primarily on tutorials or sample code, which implies that its probably not particularly robust.

  • Similarly, you inconsitantly print to stderr, stdout and sometimes not at all. Again, it's probably better just to throw an exception. Printing from a low-level interface like a texture is undesirable.

  • You don't have any way to bind the texture to make it current so it can be used. This essentially renders every texture you load except for the last one useless.

  • load() has a very poor method of extracting the extension that can result in naughty behavior if the string isn't well formed (for example, if the string is less than three characters). This is unstable.

  • From a high level perspective, I don't think binding together the texture itself, and the loading of that texture, is good design. Among other issues, it makes for some obnoxious rentrancy issues. For example, right now if I call load() twice, memory is leaked.

  • In fact, since you don't have a destructor, you leak memory anyway.



Overall, it's a respectable first attempt but needs a lot of work before it can compete with other available texture loading utility code for OpenGL (such as the OpenIL library). Keep at it!

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Quote:

* How about some documentation?

Maybe in the future? Is just a class!
Quote:

* Don't put "using namespace std;" in header files! You've polluted the global namespace and defeated the entire purpose of namespaces.

My mistake. Now on .cpp.
Quote:

* What's with TOETexture? Just call it Texture and place it in a namespace. Prefixing class names is generally sort of useless; namespaces do a much better job.

I name all my classes in that way(of this project). I see no problem with that.
Quote:

* You #include <string> but you use C strings for all your function parameters. Why?

I use std::string just for the load method and _fileName attribute. Pass const char* for the other methods because they need to. ifstream just accept const char* as a parameter to open() or constructor. And fopen too. So...
Quote:

* Your public interface has very poor naming conventions. "w()" and "h()" and "bpp()" are terrible names.

This is a texture class. So a texture.w() is a little obvious you don't think? But I can change this. No problem.
( I wrote in that way because I saw in platically all library loaders, they implement member of a struct or method of a class named w or w(), to call image width. )
Quote:

* You don't have a way of selectively disabling the loads I don't want to use. For example, lets say I only want to use the PNG functionality. You should have preprocessor switches I can set to skip the TIFF, et cetera, functionality so I don't have to link with all these extra libraries that I will never use.

I'll fix this.
Quote:

* Why is _OGLfilter a float?

Because void glTexParameterf( GLenum target, GLenum pname, GLfloat param ).
Sure, I can call glTexParameteri(). Humm, ok, changed this. But I do not saw problem.
Quote:

* You handle errors by returning magic numbers. You should really throw exceptions in many of these cases, or at the very least return enumeration values. When I recieve a return code of 4 from readBMP(), I have no idea what it means. This is not useful at all.

Yeah, was thinking in a good way to do that... try - catch()?
Quote:

* Your bitmap handling is pretty restrictive, isn't it? You only support certain bitmap color formats and such. Other types, like TGA, seem equally artificially restricted.

You mean only to support 24/32 bits RGB/BGR compressed or uncompressed formats? I think is enought. I'll not put support here for indexed images. Anybody still use that?
I was thinking in support Greyscale images, but I'm not sure.
Quote:

* You mix C style IO (the JPEG loader) and C++ style IO (the bitmap loader). This has rather negative implications... the overall lack of consistency in the style of the code and the comments suggests this code is based primarily on tutorials or sample code, which implies that its probably not particularly robust.

Because void jpeg_stdio_src(j_decompress_ptr cinfo, FILE * infile); I cannot use fstream here(I thinked in that problem yes, but I have no choice), or can I?
Quote:

* Similarly, you inconsitantly print to stderr, stdout and sometimes not at all. Again, it's probably better just to throw an exception. Printing from a low-level interface like a texture is undesirable.

Forget to throw out these things. Now is clean.
Quote:

* You don't have any way to bind the texture to make it current so it can be used. This essentially renders every texture you load except for the last one useless.

No, was thinking on that functionality too.
Quote:

* load() has a very poor method of extracting the extension that can result in naughty behavior if the string isn't well formed (for example, if the string is less than three characters). This is unstable.

Don't thinked on that. Man, this is why open source is do great! Thanks for that!
The name now must have at least 5 characters.
Quote:

* From a high level perspective, I don't think binding together the texture itself, and the loading of that texture, is good design. Among other issues, it makes for some obnoxious rentrancy issues. For example, right now if I call load() twice, memory is leaked.

Quote:

* In fact, since you don't have a destructor, you leak memory anyway.

I made a fix. Look and tell me what you think.


Thank you man! This was of great help! hummmm your name in credits? :)

HEADER .hpp

/*
The Open Engine
Copyright (C) 2006 Johnny Birnfeld https://sourceforge.net/projects/theopenengine

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

*/



#ifndef TOE_TEXTURE_H
#define TOE_TEXTURE_H

#include <string>

class TOETexture{
std::string _fileName;
int _w;
int _h;
short int _bpp;
unsigned int _id;
unsigned char *_data;
unsigned long _dataSize;

int _OGLfilter;

int readBMP( const char* );
int readJPG( const char* );
int readPNG( const char* );
int readTIF( const char* );
int readTGA( const char* );
int readPCX( const char* );
int readDDS( const char* );
int generateTexture();
void* combine( void*, size_t, void*, size_t );
int tgaLoadRawData( unsigned char* );
int tgaLoadRLEData( unsigned char* );
void tgaBGRtoRGB();
void flip();
public:
TOETexture();
~TOETexture();
int load( std::string );
int load( std::string, int );
std::string fileName();
unsigned int width();unsigned int height();
unsigned int bpp();
unsigned int id();

void createInMemoryTexture( void* );
};

#endif




BODY .cpp

/*
The Open Engine
Copyright (C) 2006 Johnny Birnfeld https://sourceforge.net/projects/theopenengine

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

*/



#include "TOETexture.hpp"
#include <iostream>
#include <fstream>
#include <GL/glu.h>

extern "C" {
#include <jpeglib.h>
#include <jerror.h>
}
#include <png.h>
#include <tiffio.h>

using namespace std;

int TOETexture::readBMP( const char *filename ){
unsigned short int bfType;
long int bfOffBits;
short int biPlanes;

ifstream ifile(filename);
if ( !ifile.good() )
return 1; //File not found or corrupted.
ifile.read( (char*)&bfType, sizeof(short int) );
if (bfType != 19778){
return 2; //Not a Bitmap-File
}

ifile.seekg(8, ios::cur); //skip file size and reserved fields of bitmap file header
ifile.read( (char*)&bfOffBits, sizeof(long int) ); //get the position of the actual bitmap data
ifile.seekg(4, ios::cur); //skip size of bitmap info header
ifile.read( (char*)&this->_w, sizeof(int) ); //get the width of the bitmap
ifile.read( (char*)&this->_h, sizeof(int) ); //get the heigth of the bitmap
ifile.read( (char*)&biPlanes, sizeof(short int) ); //get the number of planes (must be set to 1)
if (biPlanes != 1){
return 3; //number of Planes not 1!
}
ifile.read( (char*)&this->_bpp, sizeof(short int) ); //get the number of bits per pixel
if (this->_bpp != 24){
return 4; //Bits per Pixel not 24!
}

_dataSize = this->_w * this->_h * 3; //calculate the size of the image in bytes
_data = new unsigned char[_dataSize];

ifile.seekg(bfOffBits, ios::beg); //seek to the actual data
ifile.read( (char*)_data, _dataSize ); //read data

//swap red and blue (bgr -> rgb)
unsigned char temp;
for ( unsigned int i = 0; i < _dataSize; i += 3 ){
temp = _data[i];
_data[i] = _data[i + 2];
_data[i + 2] = temp;
}

ifile.close();

this->_fileName = filename;

return 0;
}

int TOETexture::readJPG( const char* filename ){

FILE *file;
struct jpeg_decompress_struct cinfo;
struct jpeg_error_mgr jerr;
volatile JSAMPROW row = 0;
JSAMPROW rowptr[1];
uint i,j,nrows;

cinfo.err = jpeg_std_error(&jerr);
jpeg_create_decompress(&cinfo);

/* make sure the file is there and open it read-only (binary) */
if ((file = fopen(filename, "rb")) == NULL){
return 1; //File not found.
}
jpeg_stdio_src(&cinfo, file);
jpeg_read_header(&cinfo, true);
jpeg_start_decompress(&cinfo);

this->_w = cinfo.output_width;
this->_h = cinfo.output_height;
this->_bpp = cinfo.jpeg_color_space*8; //JPEG images do not handle alpha channel.

row = (JSAMPROW)calloc(1,cinfo.image_width * cinfo.output_components
* sizeof(JSAMPLE));

_dataSize = cinfo.image_width * cinfo.image_height * cinfo.output_components * sizeof(JSAMPLE);
_data = (unsigned char*)malloc(_dataSize);
rowptr[0] = row;

for ( i = 0; i < cinfo.output_height; i++ ) {
nrows = jpeg_read_scanlines(&cinfo, rowptr, 1);
if (nrows != 1) {
return 5;
}

for ( j = 0; j < cinfo.output_width*cinfo.output_components; j++ )
_data[(cinfo.output_height-1-i)*cinfo.output_width*cinfo.output_components+j] = row[j];

}

jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
free(row);

this->_fileName = filename;

return 0;
}

int TOETexture::readPNG( const char* filename ){
unsigned int y;

png_structp png_ptr;
png_infop info_ptr;
int number_of_passes;
png_bytep * row_pointers;

char header[8]; // 8 is the maximum size that can be checked

/* open file and test for it being a png */
FILE *fp = fopen(filename, "rb");
if (!fp)
return 1; //File not found
fread(header, 1, 8, fp);
if (png_sig_cmp((png_byte*)header, 0, 8))
return 2; //Not a valid file

/* initialize stuff */
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

if (!png_ptr)
return -1; //png_create_read_struct failed

info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
return -1; //png_create_info_struct failed

if (setjmp(png_jmpbuf(png_ptr)))
return -1; //Error during init_io

png_init_io(png_ptr, fp);
png_set_sig_bytes(png_ptr, 8);

png_read_info(png_ptr, info_ptr);

number_of_passes = png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info_ptr);

/* read file */
if (setjmp(png_jmpbuf(png_ptr)))
return -1; //Error during read_image

row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * info_ptr->height);
for ( y=0; y<info_ptr->height; y++ )
row_pointers[y] = (png_byte*) malloc(info_ptr->rowbytes);

png_read_image(png_ptr, row_pointers);



this->_w = info_ptr->width;
this->_h = info_ptr->height;
this->_bpp = info_ptr->bit_depth;
if ( info_ptr->color_type == PNG_COLOR_TYPE_RGBA ){
this->_bpp *= 4;
}else{
if ( info_ptr->color_type == PNG_COLOR_TYPE_RGB ){
this->_bpp *= 3;
}else{
return 2;
}
}
_dataSize = this->_h * info_ptr->rowbytes;
_data = new unsigned char[_dataSize];

int tszdata=0;
for ( int c=0; c<this->_h; c++ ){
_data = (unsigned char*)combine( _data, tszdata, row_pointers[c], info_ptr->rowbytes );
tszdata += info_ptr->rowbytes;
}

this->_fileName = filename;




/* finish decompression and release memory */
png_read_end (png_ptr, NULL);
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
/* we don't need row pointers anymore */
free (row_pointers);

fclose(fp);
//Done reading .png file

return 0;
}

int TOETexture::readTIF( const char *filename ){
TIFFRGBAImage img;
uint32 *raster;
size_t npixels;

TIFF *tif;
char emsg[1024];
tif = TIFFOpen(filename, "r");
if (tif == NULL) {
return 1;
}
if ( TIFFRGBAImageBegin( &img, tif, 0, emsg ) ){
npixels = img.width * img.height;
raster = (uint32 *) _TIFFmalloc(npixels * /*img.samplesperpixel*/sizeof(uint32));
if (raster != NULL) {
if (TIFFRGBAImageGet(&img, raster, img.width, img.height) == 0) {
TIFFError(filename, emsg);
return 2;
}
}
TIFFRGBAImageEnd(&img);
}else{
TIFFError(filename, emsg);
return -1;
}

this->_w = img.width;
this->_h = img.height;
this->_bpp = 32/*img.bitspersample * img.samplesperpixel*/;
_dataSize = this->_w * this->_h * this->_bpp/8;
_data = new unsigned char[_dataSize];
memcpy( _data, raster, _dataSize );
this->_fileName = filename;


TIFFClose(tif);
return 0;
}

int TOETexture::readTGA( const char *filename ){

ifstream ifile;
unsigned long fileSize;
unsigned char *pData;
char bEnc;

ifile.open( filename,ios::binary );
if(ifile==NULL)
return 1;

// Get file size
ifile.seekg(0,ios_base::end);
fileSize=ifile.tellg();
ifile.seekg(0,ios_base::beg);

pData = new unsigned char[fileSize];
if(pData==NULL){
ifile.close();
return -1;
}

// Read the file into memory
ifile.read((char*)pData,fileSize);
ifile.close();


//Read Header
short ColMapStart,ColMapLen;
short x1,y1,x2,y2;

if( pData[1] > 1 ) // 0 (RGB) and 1 (Indexed) are the only types we know about
return 2; //Not a TGA file, or not supported format.

bEnc = pData[2]; // Encoding flag 1 = Raw indexed image
// 2 = Raw RGB
// 3 = Raw greyscale
// 9 = RLE indexed
// 10 = RLE RGB
// 11 = RLE greyscale
// 32 & 33 Other compression, indexed

if( bEnc > 11 or bEnc == 1 or bEnc == 9 ) // We don't want 32 or 33. And engine does not read indexed images too.
return 2;


// Get palette info
memcpy(&ColMapStart,&pData[3],2);
memcpy(&ColMapLen,&pData[5],2);

// Reject indexed images if not a VGA palette (256 entries with 24 bits per entry)
if(pData[1]==1) // Indexed
{
if(ColMapStart!=0 || ColMapLen!=256 || pData[7]!=24)
return 2;
}

// Get image window and produce width & height values
memcpy(&x1,&pData[8],2);
memcpy(&y1,&pData[10],2);
memcpy(&x2,&pData[12],2);
memcpy(&y2,&pData[14],2);

this->_w = (x2-x1);
this->_h = (y2-y1);

if(this->_w<1 || this->_h<1)
return 2;

// Bits per Pixel
this->_bpp = pData[16];

// Check flip / interleave byte
if(pData[17]>32) // Interleaved data
return 2;

// Calculate image size
this->_dataSize=(this->_w * this->_h * (this->_bpp/8));
//Read Header


switch(bEnc)
{
case 2: // Raw RGB
{
// Check filesize against header values
if((this->_dataSize+18+pData[0])>fileSize)
return 2;

// Double check image type field
if(pData[1]!=0)
return 2;

// Load image data
if( tgaLoadRawData( pData )!=0 )
return -1;

tgaBGRtoRGB(); // Convert to RGB
break;
}

case 10: // RLE RGB
{
// Double check image type field
if( pData[1] != 0 )
return 2;

// Load image data
if( tgaLoadRLEData( pData ) != 0 )
return -1;

tgaBGRtoRGB(); // Convert to RGB
break;
}

default:
return 2;
}

// Check flip bit
//if((pData[17] & 0x20)==0){
// flip();
//}

// Release file memory
delete [] pData;
pData = NULL;

this->_fileName = filename;

return 0;
}

int TOETexture::readPCX( const char *filename ){

struct PCXheader {
unsigned char Manufacturer;
unsigned char Version;
unsigned char Encoding;
unsigned char BitsPerPixel;
short int Xmin, Ymin, Xmax, Ymax;
short int HDpi, VDpi;
unsigned char Colormap[48];
unsigned char Reserved;
unsigned char NPlanes;
short int BytesPerLine;
short int PaletteInfo;
short int HscreenSize;
short int VscreenSize;
unsigned char Filler[54];
};

struct PCXheader pcxh;
int bpl;
unsigned char *row, *buf = NULL;

ifstream ifile(filename);
if ( !ifile.good() ){
return 1;
}

ifile.read( (char*)&pcxh, sizeof(pcxh) );

this->_w = (pcxh.Xmax - pcxh.Xmin) + 1;
this->_h = (pcxh.Ymax - pcxh.Ymin) + 1;
this->_bpp = pcxh.BitsPerPixel * pcxh.NPlanes;
if ( this->_bpp != 24 ){
ifile.close();
return 2;
}

this->_dataSize = this->_w*this->_h*(this->_bpp/8);
this->_data = new unsigned char[this->_dataSize];


bpl = pcxh.NPlanes * pcxh.BytesPerLine;
buf = new unsigned char[bpl];
row = this->_data;
for ( int y=0; y<this->_h; ++y ) {
/* decode a scan line to a temporary buffer first */
int i, count = 0;
unsigned char ch;
unsigned char *dst = buf;
for(i = 0; i < bpl; i++) {
if(!count) {
ifile.read( (char*)&ch, 1 );
if( (ch & 0xc0) == 0xc0) {
count = ch & 0x3f;
ifile.read( (char*)&ch, 1 );
} else
count = 1;
}
dst[i] = ch;
count--;
}

/* de-interlace planes */
unsigned char *src = buf;
int plane;
for(plane = 0; plane < pcxh.NPlanes; plane++){
int x;
dst = row + plane;
for(x = 0; x < this->_w; x++) {
*dst = *src++;
dst += pcxh.NPlanes;
}
}
row += this->_dataSize/this->_h;
}
delete[] buf;
ifile.close();

flip();

this->_fileName = filename;

return 0;
}

int TOETexture::readDDS( const char *filename ){
return 1;
}

int TOETexture::generateTexture(){

glGenTextures( 1, &this->_id );
glBindTexture( GL_TEXTURE_2D, this->_id );

if ( this->_OGLfilter == GL_NEAREST ){ //NORMAL
if ( this->_bpp != 32 ){ //image does not have alpha channel
glTexImage2D( GL_TEXTURE_2D, 0, 3,
this->_w, this->_h,
0, GL_RGB, GL_UNSIGNED_BYTE,
_data );
}else{
glTexImage2D( GL_TEXTURE_2D, 0, 4,
this->_w, this->_h,
0, GL_RGBA, GL_UNSIGNED_BYTE,
_data );
}
}else{ //MIPMAP
if ( this->_bpp != 32 ){ //image does not have alpha channel
gluBuild2DMipmaps(GL_TEXTURE_2D, 3,
this->_w, this->_h,
GL_RGB, GL_UNSIGNED_BYTE,
_data);
}else{
gluBuild2DMipmaps(GL_TEXTURE_2D, 4,
this->_w, this->_h,
GL_RGBA, GL_UNSIGNED_BYTE,
_data);
}

}

if ( this->_OGLfilter == GL_NEAREST ){
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}else{
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
}
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, this->_OGLfilter);

glBindTexture( GL_TEXTURE_2D, 0 ); //Unbind current texture.
return 0;
}

void* TOETexture::combine (void *o1, size_t s1, void *o2, size_t s2){
void *result = malloc(s1 + s2);
if (result != NULL)
mempcpy(mempcpy(result, o2, s2), o1, s1);
return result;
}

int TOETexture::tgaLoadRawData( unsigned char* ppData ) // Load uncompressed image data
{
short iOffset;

this->_data=new unsigned char[this->_dataSize];

if(this->_data==NULL)
return -1;

iOffset = ppData[0]+18; // Add header to ident field size

if(ppData[1]==1) // Indexed images
iOffset+=768; // Add palette offset

memcpy(this->_data,&ppData[iOffset],this->_dataSize);

return 0;
}

int TOETexture::tgaLoadRLEData( unsigned char* ppData ) // Load RLE compressed image data
{
short iOffset,iPixelSize;
unsigned char *pCur;
unsigned long Index=0;
unsigned char bLength,bLoop;

// Calculate offset to image data
iOffset=ppData[0]+18;

// Add palette offset for indexed images
if(ppData[1]==1)
iOffset+=768;

// Get pixel size in bytes
iPixelSize=this->_bpp/8;

// Set our pointer to the beginning of the image data
pCur=&ppData[iOffset];

// Allocate space for the image data
this->_data=new unsigned char[this->_dataSize];

if(this->_data==NULL)
return -1;

// Decode
while(Index<this->_dataSize)
{
if(*pCur & 0x80) // Run length chunk (High bit = 1)
{
bLength=*pCur-127; // Get run length
pCur++; // Move to pixel data

// Repeat the next pixel bLength times
for(bLoop=0;bLoop!=bLength;++bLoop,Index+=iPixelSize)
memcpy(&this->_data[Index],pCur,iPixelSize);

pCur+=iPixelSize; // Move to the next descriptor chunk
}
else // Raw chunk
{
bLength=*pCur+1; // Get run length
pCur++; // Move to pixel data

// Write the next bLength pixels directly
for(bLoop=0;bLoop!=bLength;++bLoop,Index+=iPixelSize,pCur+=iPixelSize)
memcpy(&this->_data[Index],pCur,iPixelSize);
}
}

return 0;
}

void TOETexture::tgaBGRtoRGB() // Convert BGR to RGB (or back again)
{
unsigned long Index,nPixels;
unsigned char *bCur;
unsigned char bTemp;
short iPixelSize;

// Set ptr to start of image
bCur = this->_data;

// Calc number of pixels
nPixels = this->_w*this->_h;

// Get pixel size in bytes
iPixelSize = this->_bpp/8;

for(Index=0;Index!=nPixels;Index++) // For each pixel
{
bTemp=*bCur; // Get Blue value
*bCur=*(bCur+2); // Swap red value into first position
*(bCur+2)=bTemp; // Write back blue to last position

bCur+=iPixelSize; // Jump to next pixel
}

}

void TOETexture::flip( ) // Flips the image vertically (Why store images upside down?)
{
unsigned char bTemp;
unsigned char *pLine1, *pLine2;
int iLineLen,iIndex;

iLineLen=this->_w*(this->_bpp/8);
pLine1=this->_data;
pLine2=&this->_data[iLineLen * (this->_h - 1)];

for( ;pLine1<pLine2;pLine2-=(iLineLen*2))
{
for(iIndex=0;iIndex!=iLineLen;pLine1++,pLine2++,iIndex++)
{
bTemp=*pLine1;
*pLine1=*pLine2;
*pLine2=bTemp;
}
}

}







///public methods
TOETexture::TOETexture(){
this->_fileName = "";
this->_w = 0;
this->_h = 0;
this->_bpp = 0;
this->_id = 0;
this->_data = NULL;
this->_dataSize = 0;

this->_OGLfilter = GL_LINEAR_MIPMAP_LINEAR; //Default value to the texture filter(Trilinear).
}

TOETexture::~TOETexture(){
delete[] this->_data;

this->_fileName = "";
this->_w = 0;
this->_h = 0;
this->_bpp = 0;
this->_id = 0;
this->_data = NULL;
this->_dataSize = 0;
}

int TOETexture::load( string filename ){
return this->load( filename, this->_OGLfilter );
}

int TOETexture::load( string filename, int filterToUse ){
if ( filename.length() < 5 ){
cout << "Error loading " << filename << ". Filename is too short!" << endl;
return -2;
}
if ( this->_data ){
cout << "Error loading " << filename << ". File is already loaded! Will not load twice." << endl;
return -3;
}

this->_OGLfilter = filterToUse;
int returnValue = 0;
string ext = filename.substr( filename.length()-3, filename.length()-1 );
string extl = filename.substr( filename.length()-4, filename.length()-1 );

if ( ext == "bmp" ){
returnValue = readBMP( filename.c_str() );
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}

if ( ext == "jpg" or extl == "jpeg" ){
returnValue = readJPG( filename.c_str() );
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}

if ( ext == "png" ){
returnValue = readPNG( filename.c_str() );
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}

if ( ext == "tif" or extl == "tiff" ){
returnValue = readTIF( filename.c_str() );
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}

if ( ext == "tga" ){
returnValue = readTGA( filename.c_str() );
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}


if ( ext == "pcx" ){
returnValue = readPCX( filename.c_str() );
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}

if ( ext == "dds" ){
returnValue = readDDS( filename.c_str() );
cout << "INFO: " << this->_w << endl;
cout << "INFO: " << this->_h << endl;
cout << "INFO: " << this->_bpp << endl;
cout << "INFO: " << this->_fileName << endl;
if ( returnValue == 0 ){
returnValue = generateTexture();
}
}

switch( returnValue ){
case -1:
cout << "Error loading " << filename << ". Internal error reading image." << endl;
break;
case 1:
cout << "Error loading " << filename << ". File not found." << endl;
break;
case 2:
cout << "Error loading " << filename << ". Unexpected file format. Wrong extension?" << endl;
break;
case 3:
cout << "Error loading " << filename << ". Number of Planes not 1." << endl;
break;
case 4:
cout << "Error loading " << filename << ". Unexpected bits per pixel." << endl;
break;
case 5:
cout << "Error loading " << filename << ". Unexpected number of rows." << endl;
break;
case 50:
cout << "Error loading " << filename << ". Could not generate texture." << endl;
break;
}

return returnValue;
}

string TOETexture::fileName(){
return this->_fileName;
}

unsigned int TOETexture::width(){
return this->_w;
}

unsigned int TOETexture::height(){
return this->_h;
}

unsigned int TOETexture::bpp(){
return this->_bpp;
}

unsigned int TOETexture::id(){
return this->_id;
}

void TOETexture::createInMemoryTexture( void* ){

}





phantom, I'm just want to write a texture class, not a complete library :) Is a different approach.
Ah, I wanted to make you a question: Your project just runs on win32?

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Maybe in the future? Is just a class!

Irrelevant. It should be documented. Especially since your public interface is next to incomprehensible. Especially since you are providing it for others to use.

Quote:

I name all my classes in that way(of this project). I see no problem with that.

It adds no useful information. The functionality can be duplicated (in a better fashion) by namespaces. It hinders readability. Depending the layout of your project files and their names, it can make project navigation a chore.

Quote:

I use std::string just for the load method and _fileName attribute. Pass const char* for the other methods because they need to. ifstream just accept const char* as a parameter to open() or constructor. And fopen too. So...

std::string has a method called c_str() that will return a const char* representation of the string. So in the case of fopen(), you can use:

FILE *fp = fopen(some_std_string.c_str(),"rb");

or something similar. Using const char* for strings is a chore.

Quote:

This is a texture class. So a texture.w() is a little obvious you don't think? But I can change this. No problem.
( I wrote in that way because I saw in platically all library loaders, they implement member of a struct or method of a class named w or w(), to call image width. )

No, I don't think it's obvious. It's bad practice, and it's not self-documenting. The fact that you've seen other code use it doesn't mean it's okay, it means that other code is poor.

w() and h() might be intuitable. But consider, for example, bpp()?

What on earth does that mean? Bits per pixel or bytes per pixel? both are perfectly useful numbers (neither is neccessarily more or less useful than the other). So which is it? The user won't know unless he digs through your source code.

Quote:

Sure, I can call glTexParameteri(). Humm, ok, changed this. But I do not saw problem.

Because it's silly to use a float to store values that are integers. You never need that value to be a float, so why make it a float?

Quote:

Yeah, was thinking in a good way to do that... try - catch()?

It is unlikely that you will need to catch any exceptions in this code, since it is very low level and would not know what to do about the failure (the only exception would be if you wanted to translate the exceptions and rethrow). Therefore you won't need to use try/catch blocks.

However, I may have misspoke. Writing exception-safe code is hard and might be something you want to postpone until you have more programming experience.

You should at least convert your returned magic numbers to values that are part of some kind of error code enumeration, however.

Quote:

You mean only to support 24/32 bits RGB/BGR compressed or uncompressed formats? I think is enought. I'll not put support here for indexed images. Anybody still use that?
I was thinking in support Greyscale images, but I'm not sure.

Yes, people still use indexed formats. They use grayscale formats, too. The key to writing code suitable for others to use is to realize that you generally can't expect your users to need to use the code in exactly the way you'd use it.

Quote:

Because void jpeg_stdio_src(j_decompress_ptr cinfo, FILE * infile); I cannot use fstream here(I thinked in that problem yes, but I have no choice), or can I?

Hmm, fair enough. I don't know enough about libjpeg, so perhaps that does mean FILE* are you only options here.

Quote:

Thank you man!

No problem.

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Original post by Tsumuji
phantom, I'm just want to write a texture class, not a complete library :) Is a different approach.
Ah, I wanted to make you a question: Your project just runs on win32?


The only difference is that I split up what you do in one class over a number of logical units; the benfit of more software engineering experiance I guess [smile]

GTL has successfully been compiled and tested for Win32, Win64 (x64) and ARM9 for the GP2x handheld console (which runs linux).
In theory, because it uses C++ and crossplatorm libs it should work on any system which uses the same Endian as Intel/AMD CPUs, the BMP and DDS code might have some 'issues' with systems which don't use it (PPC for example...), I should fix that.

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You covered pretty much every point above, except one, which I would like to focus on a bit.
Quote:
Original post by Tsumuji
Quote:

* You mix C style IO (the JPEG loader) and C++ style IO (the bitmap loader). This has rather negative implications... the overall lack of consistency in the style of the code and the comments suggests this code is based primarily on tutorials or sample code, which implies that its probably not particularly robust.

Because void jpeg_stdio_src(j_decompress_ptr cinfo, FILE * infile); I cannot use fstream here(I thinked in that problem yes, but I have no choice), or can I?

Any library worth it's name that requires I/O of some kind should have a way to abstract the I/O. Never used the JPEG library you use, so can't say whether it have it or not, but look for some user I/O callbacks.

Common ways are to register read/write callbacks, which the library use for reading/writing/whatever. For example, the read callback prototype can be something like:

int read(int n, void *p, void *user)

The user pointer being some user defined value, so you can pass the address of a istream object, letting you read from any stream derived from the standard C++ input stream.

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      When sampling a texture in a shader, the texture sampler was traditionally specified as separate object that was bound to the pipeline at run time or set as part of the texture object itself. However, in most cases it is known beforehand what kind of sampler will be used in the shader. Next-generation APIs expose new type of sampler called static sampler that can be initialized directly in the pipeline state. Diligent Engine exposes this functionality: when creating a shader, textures can be assigned static samplers. If static sampler is assigned, it will always be used instead of the one initialized in the texture shader resource view. To initialize static samplers, prepare an array of StaticSamplerDesc structures and initialize StaticSamplers and NumStaticSamplers members. Static samplers are more efficient and it is highly recommended to use them whenever possible. On older APIs, static samplers are emulated via generic sampler objects.
      The following is an example of shader initialization:
      ShaderCreationAttribs Attrs; Attrs.Desc.Name = "MyPixelShader"; Attrs.FilePath = "MyShaderFile.fx"; Attrs.SearchDirectories = "shaders;shaders\\inc;"; Attrs.EntryPoint = "MyPixelShader"; Attrs.Desc.ShaderType = SHADER_TYPE_PIXEL; Attrs.SourceLanguage = SHADER_SOURCE_LANGUAGE_HLSL; BasicShaderSourceStreamFactory BasicSSSFactory(Attrs.SearchDirectories); Attrs.pShaderSourceStreamFactory = &BasicSSSFactory; ShaderVariableDesc ShaderVars[] = {     {"g_StaticTexture", SHADER_VARIABLE_TYPE_STATIC},     {"g_MutableTexture", SHADER_VARIABLE_TYPE_MUTABLE},     {"g_DynamicTexture", SHADER_VARIABLE_TYPE_DYNAMIC} }; Attrs.Desc.VariableDesc = ShaderVars; Attrs.Desc.NumVariables = _countof(ShaderVars); Attrs.Desc.DefaultVariableType = SHADER_VARIABLE_TYPE_STATIC; StaticSamplerDesc StaticSampler; StaticSampler.Desc.MinFilter = FILTER_TYPE_LINEAR; StaticSampler.Desc.MagFilter = FILTER_TYPE_LINEAR; StaticSampler.Desc.MipFilter = FILTER_TYPE_LINEAR; StaticSampler.TextureName = "g_MutableTexture"; Attrs.Desc.NumStaticSamplers = 1; Attrs.Desc.StaticSamplers = &StaticSampler; ShaderMacroHelper Macros; Macros.AddShaderMacro("USE_SHADOWS", 1); Macros.AddShaderMacro("NUM_SHADOW_SAMPLES", 4); Macros.Finalize(); Attrs.Macros = Macros; RefCntAutoPtr<IShader> pShader; m_pDevice->CreateShader( Attrs, &pShader );
      Creating the Pipeline State Object
      After all required shaders are created, the rest of the fields of the PipelineStateDesc structure provide depth-stencil, rasterizer, and blend state descriptions, the number and format of render targets, input layout format, etc. For instance, rasterizer state can be described as follows:
      PipelineStateDesc PSODesc; RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; RasterizerDesc.AntialiasedLineEnable = False; Depth-stencil and blend states are defined in a similar fashion.
      Another important thing that pipeline state object encompasses is the input layout description that defines how inputs to the vertex shader, which is the very first shader stage, should be read from the memory. Input layout may define several vertex streams that contain values of different formats and sizes:
      // Define input layout InputLayoutDesc &Layout = PSODesc.GraphicsPipeline.InputLayout; LayoutElement TextLayoutElems[] = {     LayoutElement( 0, 0, 3, VT_FLOAT32, False ),     LayoutElement( 1, 0, 4, VT_UINT8, True ),     LayoutElement( 2, 0, 2, VT_FLOAT32, False ), }; Layout.LayoutElements = TextLayoutElems; Layout.NumElements = _countof( TextLayoutElems ); Finally, pipeline state defines primitive topology type. When all required members are initialized, a pipeline state object can be created by IRenderDevice::CreatePipelineState() method:
      // Define shader and primitive topology PSODesc.GraphicsPipeline.PrimitiveTopologyType = PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE; PSODesc.GraphicsPipeline.pVS = pVertexShader; PSODesc.GraphicsPipeline.pPS = pPixelShader; PSODesc.Name = "My pipeline state"; m_pDev->CreatePipelineState(PSODesc, &m_pPSO); When PSO object is bound to the pipeline, the engine invokes all API-specific commands to set all states specified by the object. In case of Direct3D12 this maps directly to setting the D3D12 PSO object. In case of Direct3D11, this involves setting individual state objects (such as rasterizer and blend states), shaders, input layout etc. In case of OpenGL, this requires a number of fine-grain state tweaking calls. Diligent Engine keeps track of currently bound states and only calls functions to update these states that have actually changed.
      Binding Shader Resources
      Direct3D11 and OpenGL utilize fine-grain resource binding models, where an application binds individual buffers and textures to certain shader or program resource binding slots. Direct3D12 uses a very different approach, where resource descriptors are grouped into tables, and an application can bind all resources in the table at once by setting the table in the command list. Resource binding model in Diligent Engine is designed to leverage this new method. It introduces a new object called shader resource binding that encapsulates all resource bindings required for all shaders in a certain pipeline state. It also introduces the classification of shader variables based on the frequency of expected change that helps the engine group them into tables under the hood:
      Static variables (SHADER_VARIABLE_TYPE_STATIC) are variables that are expected to be set only once. They may not be changed once a resource is bound to the variable. Such variables are intended to hold global constants such as camera attributes or global light attributes constant buffers. Mutable variables (SHADER_VARIABLE_TYPE_MUTABLE) define resources that are expected to change on a per-material frequency. Examples may include diffuse textures, normal maps etc. Dynamic variables (SHADER_VARIABLE_TYPE_DYNAMIC) are expected to change frequently and randomly. Shader variable type must be specified during shader creation by populating an array of ShaderVariableDesc structures and initializing ShaderCreationAttribs::Desc::VariableDesc and ShaderCreationAttribs::Desc::NumVariables members (see example of shader creation above).
      Static variables cannot be changed once a resource is bound to the variable. They are bound directly to the shader object. For instance, a shadow map texture is not expected to change after it is created, so it can be bound directly to the shader:
      PixelShader->GetShaderVariable( "g_tex2DShadowMap" )->Set( pShadowMapSRV ); Mutable and dynamic variables are bound via a new Shader Resource Binding object (SRB) that is created by the pipeline state (IPipelineState::CreateShaderResourceBinding()):
      m_pPSO->CreateShaderResourceBinding(&m_pSRB); Note that an SRB is only compatible with the pipeline state it was created from. SRB object inherits all static bindings from shaders in the pipeline, but is not allowed to change them.
      Mutable resources can only be set once for every instance of a shader resource binding. Such resources are intended to define specific material properties. For instance, a diffuse texture for a specific material is not expected to change once the material is defined and can be set right after the SRB object has been created:
      m_pSRB->GetVariable(SHADER_TYPE_PIXEL, "tex2DDiffuse")->Set(pDiffuseTexSRV); In some cases it is necessary to bind a new resource to a variable every time a draw command is invoked. Such variables should be labeled as dynamic, which will allow setting them multiple times through the same SRB object:
      m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); Under the hood, the engine pre-allocates descriptor tables for static and mutable resources when an SRB objcet is created. Space for dynamic resources is dynamically allocated at run time. Static and mutable resources are thus more efficient and should be used whenever possible.
      As you can see, Diligent Engine does not expose low-level details of how resources are bound to shader variables. One reason for this is that these details are very different for various APIs. The other reason is that using low-level binding methods is extremely error-prone: it is very easy to forget to bind some resource, or bind incorrect resource such as bind a buffer to the variable that is in fact a texture, especially during shader development when everything changes fast. Diligent Engine instead relies on shader reflection system to automatically query the list of all shader variables. Grouping variables based on three types mentioned above allows the engine to create optimized layout and take heavy lifting of matching resources to API-specific resource location, register or descriptor in the table.
      This post gives more details about the resource binding model in Diligent Engine.
      Setting the Pipeline State and Committing Shader Resources
      Before any draw or compute command can be invoked, the pipeline state needs to be bound to the context:
      m_pContext->SetPipelineState(m_pPSO); Under the hood, the engine sets the internal PSO object in the command list or calls all the required native API functions to properly configure all pipeline stages.
      The next step is to bind all required shader resources to the GPU pipeline, which is accomplished by IDeviceContext::CommitShaderResources() method:
      m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); The method takes a pointer to the shader resource binding object and makes all resources the object holds available for the shaders. In the case of D3D12, this only requires setting appropriate descriptor tables in the command list. For older APIs, this typically requires setting all resources individually.
      Next-generation APIs require the application to track the state of every resource and explicitly inform the system about all state transitions. For instance, if a texture was used as render target before, while the next draw command is going to use it as shader resource, a transition barrier needs to be executed. Diligent Engine does the heavy lifting of state tracking.  When CommitShaderResources() method is called with COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES flag, the engine commits and transitions resources to correct states at the same time. Note that transitioning resources does introduce some overhead. The engine tracks state of every resource and it will not issue the barrier if the state is already correct. But checking resource state is an overhead that can sometimes be avoided. The engine provides IDeviceContext::TransitionShaderResources() method that only transitions resources:
      m_pContext->TransitionShaderResources(m_pPSO, m_pSRB); In some scenarios it is more efficient to transition resources once and then only commit them.
      Invoking Draw Command
      The final step is to set states that are not part of the PSO, such as render targets, vertex and index buffers. Diligent Engine uses Direct3D11-syle API that is translated to other native API calls under the hood:
      ITextureView *pRTVs[] = {m_pRTV}; m_pContext->SetRenderTargets(_countof( pRTVs ), pRTVs, m_pDSV); // Clear render target and depth buffer const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); m_pContext->ClearDepthStencil(nullptr, CLEAR_DEPTH_FLAG, 1.f); // Set vertex and index buffers IBuffer *buffer[] = {m_pVertexBuffer}; Uint32 offsets[] = {0}; Uint32 strides[] = {sizeof(MyVertex)}; m_pContext->SetVertexBuffers(0, 1, buffer, strides, offsets, SET_VERTEX_BUFFERS_FLAG_RESET); m_pContext->SetIndexBuffer(m_pIndexBuffer, 0); Different native APIs use various set of function to execute draw commands depending on command details (if the command is indexed, instanced or both, what offsets in the source buffers are used etc.). For instance, there are 5 draw commands in Direct3D11 and more than 9 commands in OpenGL with something like glDrawElementsInstancedBaseVertexBaseInstance not uncommon. Diligent Engine hides all details with single IDeviceContext::Draw() method that takes takes DrawAttribs structure as an argument. The structure members define all attributes required to perform the command (primitive topology, number of vertices or indices, if draw call is indexed or not, if draw call is instanced or not, if draw call is indirect or not, etc.). For example:
      DrawAttribs attrs; attrs.IsIndexed = true; attrs.IndexType = VT_UINT16; attrs.NumIndices = 36; attrs.Topology = PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; pContext->Draw(attrs); For compute commands, there is IDeviceContext::DispatchCompute() method that takes DispatchComputeAttribs structure that defines compute grid dimension.
      Source Code
      Full engine source code is available on GitHub and is free to use. The repository contains two samples, asteroids performance benchmark and example Unity project that uses Diligent Engine in native plugin.
      AntTweakBar sample is Diligent Engine’s “Hello World” example.

       
      Atmospheric scattering sample is a more advanced example. It demonstrates how Diligent Engine can be used to implement various rendering tasks: loading textures from files, using complex shaders, rendering to multiple render targets, using compute shaders and unordered access views, etc.

      Asteroids performance benchmark is based on this demo developed by Intel. It renders 50,000 unique textured asteroids and allows comparing performance of Direct3D11 and Direct3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

      Finally, there is an example project that shows how Diligent Engine can be integrated with Unity.

      Future Work
      The engine is under active development. It currently supports Windows desktop, Universal Windows and Android platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and support for more platforms is planned.
    • By michaeldodis
      I've started building a small library, that can render pie menu GUI in legacy opengl, planning to add some traditional elements of course.
      It's interface is similar to something you'd see in IMGUI. It's written in C.
      Early version of the library
      I'd really love to hear anyone's thoughts on this, any suggestions on what features you'd want to see in a library like this? 
      Thanks in advance!
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