Pandora [solved by my own stupidity]c++ SDL colour key not working

[dan3008]

I'm wondering if anyone can help me. I'm learning c++ and SDL by writing a game (currently for the Pandora, but I'll port it to the pyra (probably a simple recompile) when I get one) and I cant get SDL_SetColorKey to work :/

The texture loading code is taken almost asis from lazyfoo's page, and looks like this:

bool LTexture::loadFromFile( std::string path )

{
    //Get rid of preexisting texture
    free();

    //The final texture
    SDL_Texture* newTexture = NULL;

    //Load image at specified path
    SDL_Surface* loadedSurface = SDL_LoadBMP( path.c_str() );
    if( loadedSurface == NULL )
    {
        printf( "Unable to load image %s! SDL_image Error: %s\n", path.c_str(), SDL_GetError() );
    }
    else
    {
        //SDL_Surface loaded2 = SDL_DisplayFormatAlpha(loadedSurface);
        //Color key image
        SDL_SetColorKey( loadedSurface, SDL_TRUE, SDL_MapRGB( loadedSurface->format, 0, 255, 255 ) );

        //Create texture from surface pixels
        newTexture = SDL_CreateTextureFromSurface( gRenderer, loadedSurface );

        if( newTexture == NULL )
        {
            printf( "Unable to create texture from %s! SDL Error: %s\n", path.c_str(), SDL_GetError() );
        }
        else
        {
            //Get image dimensions
            mWidth = loadedSurface->w;
            mHeight = loadedSurface->h;
        }

        //Get rid of old loaded surface
        SDL_FreeSurface( loadedSurface );
    }

    //Return success
    mTexture = newTexture;
    return mTexture != NULL;
}

and the render code:

void LTexture::render( int x, int y, SDL_Rect* clip )
{
    //Set rendering space and render to screen
    SDL_Rect renderQuad = { x, y, mWidth, mHeight };

    //Set clip rendering dimensions
    if( clip != NULL )
    {
        renderQuad.w = clip->w;
        renderQuad.h = clip->h;
    }

    //Render to screen
    SDL_RenderCopy( gRenderer, mTexture, clip, &renderQuad );
}

I'm not quite sure why it isnt working :/ but i'm still getting the cyan background displayed :/

Any advice?

thanks in advance

 

[mjohansson]

Found this, dont know if its the problem, but someone might know more of the SDL source code and help further?

"EDIT: This turned out to be due to a bug in SDL_CreateTextureFromSurface, which I ended up submitting a patch for."

http://stackoverflow.com/questions/1114633/why-cant-i-use-colorkey-for-sdl-textures

More here:
http://forums.libsdl.org/viewtopic.php?t=6753&sid=28e16002e2abaaf82572b9c0bc56d1cf

 

[dan3008]

well, now i'm embarrassed... The issue was in the image, not with the softwere. When I saved out, I compressed the image down to 8bit... which had changed the colour of the background, so the colour key wouldnt have worked :/ oopsie

 

[PokeParadox]

well, now i'm embarrassed... The issue was in the image, not with the softwere. When I saved out, I compressed the image down to 8bit... which had changed the colour of the background, so the colour key wouldnt have worked :/ oopsie

Don't worry... I've done similar things before. I think in my case it was not realising that the screen colour depth was set to 16b. I was picking a colour from the screen to compare to a 32b colour that didn't exist in 16bits.