Hey all,
I'm trying to write a program which takes an SDL_Surface,
converts it to an IplImage, uses the cvBlobsLib to find
blobs, paints the blobs as spots back over the image, then converts the
output IplImage back to an SDL_Surface.
I'm almost done: only converting the IplImage back to an
SDL_Surface hasn't been done yet. This IplImage has 3
image channels and is 8 bits per pixel. I think I have two calls I can
use:
SDL_Surface *SDL_CreateRGBSurface(Uint32 flags, int width, int height, int depth, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);
SDL_Surface *SDL_CreateRGBSurfaceFrom(void *pixels, int width, int height, int depth, int pitch, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);
I'm currently trying with SDL_CreateRGBsurfaceFrom. I
have no idea, however, what the correct values of pitch, Rmask, Gmask
and Bmask are. (Amask is 0, because there is no alpha channel.)
Could anybody help me out by explaining how to do this?
Thanks!
Edit: For example, this is code I tried to use:
SDL_Surface *ipl_to_surface (IplImage *opencvimg)
{
int pitch = opencvimg->nChannels*opencvimg->width;
printf("Depth %d, nChannels %d, pitch %d\n", opencvimg->depth,
opencvimg->nChannels, pitch);
SDL_Surface *surface = SDL_CreateRGBSurfaceFrom((void*)opencvimg->imageData,
opencvimg->width,
opencvimg->height,
opencvimg->depth,
pitch,
0x0000ff, 0x00ff00, 0xff0000, 0
);
return surface;
}
(SDL Documentation writes "Pitch is the size of the scanline of the surface, in bytes, i.e. widthInPixels*bytesPerPixel.") This outputs "Depth 8, nChannels 3, pitch 1920" and displays a completely red image. I think a solution would be to convert my 8-bits image to 24-bits (1 byte per channel), but I don't know how to do that. Any ideas?
