Computer Science Canada

Convert 8 bit values to 32 bit
Author:  crossley7 [ Mon May 02, 2011 8:17 pm ]
Post subject:  Convert 8 bit values to 32 bit
I'm using Dev C++ with the G++ compiler. I am trying to create a program that reads in a bmp and converts the pixel colours to the opposite ie black becomes white.

code:

Uint8 r,g,b,a;
Uint32 pixel = get_pixel32( surface, x, y );
SDL_GetRGBA (pixel, surface->format, &r, &g, &b, &a);
r = (Uint8)255 - r;
g = (Uint8)255 - g;
b = (Uint8)255 - b;
a = (Uint8)255 - a;
pixel =(Uint8)r*1000000+(Uint8)b*10000+(Uint8)g*100+(Uint8)a;


I know that the last line is horribly wrong, but I have no idea as to what it should actually be.
Author:  Tony [ Mon May 02, 2011 8:19 pm ]
Post subject:  RE:Convert 8 bit values to 32 bit
You might be looking for http://en.wikipedia.org/wiki/Logical_shift
Author:  Raknarg [ Mon May 02, 2011 8:23 pm ]
Post subject:  RE:Convert 8 bit values to 32 bit
Your probably looking for this too ;P http://en.wikipedia.org/wiki/List_of_Latin_phrases:_I#id_est
Author:  crossley7 [ Mon May 02, 2011 8:36 pm ]
Post subject:  RE:Convert 8 bit values to 32 bit
Thanks, that is a lot of help, but I'm not sure how to implement it, but will keep working on it to see if i can figure it out

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