Specifically the code having to do with AUX_RGBImageRect objects.
I'm sure someone else has figured this out before. So how do you do it?
EDIT: I actually just figured it out.
Here is the code in case other people need it in the future:
I claim rights to none of this code.
Code: Select all
//In main file
#include "bmp.h"
AUX_RGBImageRec *LoadBMP(char *Filename) // Loads A Bitmap Image
{
FILE *File=NULL; // File Handle
if (!Filename) // Make Sure A Filename Was Given
{
return NULL; // If Not Return NULL
}
File=fopen(Filename,"r"); // Check To See If The File Exists
if (File) // Does The File Exist?
{
fclose(File); // Close The Handle
return auxDIBImageLoad(Filename); // Load The Bitmap And Return A Pointer
}
return NULL; // If Load Failed Return NULL
}
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//bmp.h
#ifndef BMP_H
#define BMP_H
class AUX_RGBImageRec
{
void convertBGRtoRGB();
public:
byte *data;
DWORD sizeX;
DWORD sizeY;
bool NoErrors;
AUX_RGBImageRec(): NoErrors(false), data(NULL) {};
AUX_RGBImageRec(const char *FileName);
~AUX_RGBImageRec();
bool loadFile(const char *FileName);
friend AUX_RGBImageRec *auxDIBImageLoad(const char *FileName);
};
#endif
Code: Select all
//In bmp.cpp
//--------------------------------------------------------------
#include <windows.h> // Header File For Windows - has structures for BMP format
#include <stdio.h> // Header File For Standard Input/Output
#include <stdlib.h>
#include "BMP.h"
/*------------------------------------------------------------------
BMP Loader - a quick and dirty substitute for GLaux
if you only use GLaux to load BMP files will load any format of a
windows DIB BMP format graphics file Only works on a windows box
Caution! memory for the data is allocated using 'new'.
In the NeHe tutorials the memory is reclaimed using 'free'.
For the small tutorials its not a big deal but not a good practice in
larger projects (heap trashing not good). J.M. Doyle : 12 Jan 2003
------------------------------------------------------------------*/
AUX_RGBImageRec *auxDIBImageLoad(const char *FileName)
{
return new AUX_RGBImageRec(FileName);
}
void AUX_RGBImageRec::convertBGRtoRGB()
{
const DWORD BitmapLength = sizeX * sizeY * 3;
byte Temp; // not quick but it works
for(DWORD i=0; i< BitmapLength; i += 3)
{
Temp = data[i];
data[i] = data[i+2];
data[i+2] = Temp;
}
}
AUX_RGBImageRec::AUX_RGBImageRec(const char *FileName): data(NULL), NoErrors(false)
{
loadFile(FileName);
}
AUX_RGBImageRec::~AUX_RGBImageRec()
{
if (data != NULL) delete data;
data = NULL;
}
bool AUX_RGBImageRec::loadFile(const char* Filename)
{
BITMAPINFO BMInfo; // need the current OpenGL device contexts in order to make use of windows DIB utilities
const HDC gldc = wglGetCurrentDC(); // a handle for the current OpenGL Device Contexts
// assume there are errors until file is loaded successfully into memory
NoErrors = false; // release old data since this object could be used to load multiple Textures
if(data != NULL) delete data; // windows needs this info to determine what header info we are looking for
BMInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER); // Get windows to determine color bit depth in the file for us
BMInfo.bmiHeader.biBitCount = 0; // Get windows to open and load the BMP file and handle the messy decompression if the file is compressed
// assume perfect world and no errors in reading file, Ha Ha
HANDLE DIBHandle = LoadImage(0,Filename, IMAGE_BITMAP, 0, 0,LR_DEFAULTCOLOR | LR_CREATEDIBSECTION | LR_LOADFROMFILE); // use windows to get header info of bitmap - assume no errors in header format
GetDIBits(gldc, (HBITMAP)DIBHandle, 0,0, NULL, &BMInfo, DIB_RGB_COLORS);
sizeX = BMInfo.bmiHeader.biWidth;
sizeY = BMInfo.bmiHeader.biHeight; // change color depth to 24 bits (3 bytes (BGR) / pixel)
BMInfo.bmiHeader.biBitCount = 24; // don't want the data compressed
BMInfo.bmiHeader.biCompression = BI_RGB;
const DWORD BitmapLength = sizeX * sizeY * 3; // 3 bytes (BGR) per pixel (24bp)
// allocate enough memory to hold the pixel data in client memory
data = new byte[BitmapLength]; // Get windows to do the dirty work of converting the BMP into the format needed by OpenGL
// if file is already 24 bit color then this is a waste of time but makes for short code
// Get the actual Texel data from the BMP object
if (GetDIBits(gldc, (HBITMAP)DIBHandle, 0, sizeY, data, &BMInfo, DIB_RGB_COLORS))
{
NoErrors = true;
convertBGRtoRGB(); // NOTE: BMP is in BGR format but OpenGL needs RGB unless you use GL_BGR_EXT
}
DeleteObject(DIBHandle); // don't need the BMP Object anymore
return NoErrors;
}
