No one can seem to help me, loading bitmap
This is supposedly very simple to do, yet I can't get it to work. It uses OpenGL functions to actually draw the bitmap but i still think it's more appropriate in the C++ board. Anyway this doesn't work and I'm wondering if I did anything wrong
code for loading the bitmap:
Code:
byte * LoadBMP(char * filename, BITMAPINFOHEADER *bih) {
byte * imageData; //THIS WILL END UP BEING OUR IMAGE READ FROM THE FILE
ifstream fin(filename, ios::in | ios::binary | ios::nocreate); //OPEN FILE
if(fin.fail())
return NULL;
fin.seekg(0, ios::end);
long filesize = fin.tellg();
fin.seekg(0, ios::beg);
byte * buffer = new byte[filesize]; //ALLOCATE TEMPORARY BUFFER
fin.read(buffer, filesize);
fin.close();
const byte * ptr = buffer; //CREATE POINTER TO BUFFER TO EXTRACT STUFF FROM THE FILE
BITMAPFILEHEADER * pHeader = (BITMAPFILEHEADER*)ptr; //EXTRACT THE BITMAPFILEHEADER TO CHECK TYPE
ptr += sizeof(BITMAPFILEHEADER); //GO PAST BITMAPFILEHEADER IN FILE
if(pHeader->bfType != BITMAP_ID) { //CHECK THE TYPE, DEFINED IN MAIN.H
MessageBox(NULL, "BITMAP ID INVALID", "BITMAP ID INVALID", MB_OK);
return NULL;
}
bih = (BITMAPINFOHEADER*) ptr; //EXTRACT OUR BITMAPINFOHEADER
ptr += sizeof(BITMAPINFOHEADER);
imageData = new byte[bih->biSizeImage];
imageData = (byte*)ptr; //EXTRACT ALL OF THE INFORMATION FOR THE IMAGE
//SWAP THE R AND B VALUES OF THE IMAGE DATA
return imageData; //RETURN IT
}
code used in main to actually draw the bitmap (this is opengl specific stuff):
Code:
//globals
byte * bitmap;
BITMAPINFOHEADER bih;
//...
glRasterPos2i(100, 100); //START DRAWING AT THESE PIXELS
glPixelStorei(GL_UNPACK_ALIGNMENT, 4); //SET MEMORY ALIGNMENT
glDrawPixels(bih.biWidth, bih.biHeight, GL_RGB, GL_UNSIGNED_BYTE, bitmap); //DRAW STUFF!
this should be displaying something, albeit the fact that I should have switched the red and blue values with the current mode I'm using in drawpixels (supposedly with opengl 1.2 and later you can use GL_BGR to draw, but that enumerated type doesn't seem to exist).
thanks if anyone can help this poor soul
