Discussion :

[guitz]

Bonjour,

Je blit un fichier .png et je ne sais pas comment obtenir la transparence ( à la place j'ai un fond blanc)

Voici mon code :

Code :

Sélectionner tout - Visualiser dans une fenêtre à part

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...
 
bool init()
{
	//Initialization flag
	bool success = true;
 
	//Initialize SDL
	if( SDL_Init( SDL_INIT_VIDEO ) < 0 )
	{
		printf( "SDL could not initialize! SDL Error: %s\n", SDL_GetError() );
		success = false;
	}
	else
	{
		//Create window
		gWindow = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );
		if( gWindow == NULL )
		{
			printf( "Window could not be created! SDL Error: %s\n", SDL_GetError() );
			success = false;
		}
		else
		{
			//Initialize PNG loading
			int imgFlags = IMG_INIT_PNG;
			if( !( IMG_Init( imgFlags ) & imgFlags ) )
			{
				printf( "SDL_image could not initialize! SDL_image Error: %s\n", IMG_GetError() );
				success = false;
			}
			else
			{
				//Get window surface
				gScreenSurface = SDL_GetWindowSurface( gWindow );
			}
		}
	}
 
	return success;
}
 
 
bool loadMedia()
{
	//Loading success flag
	bool success = true;
 
	//Load PNG surface
	gPNGSurface = loadSurface( "images/ball1.png" );
	if( gPNGSurface == NULL )
	{
		printf( "Failed to load PNG image!\n" );
		success = false;
	}
 
	return success;
}
 
void close()
{
	//Free loaded image
	SDL_FreeSurface( gPNGSurface );
	gPNGSurface = NULL;
 
	//Destroy window
	SDL_DestroyWindow( gWindow );
	gWindow = NULL;
 
	//Quit SDL subsystems
	IMG_Quit();
	SDL_Quit();
}
 
SDL_Surface* loadSurface( std::string path )
{
	//The final optimized image
	SDL_Surface* optimizedSurface = NULL;
 
	//Load image at specified path
	SDL_Surface* loadedSurface = IMG_Load( path.c_str() );
	if( loadedSurface == NULL )
	{
		printf( "Unable to load image %s! SDL_image Error: %s\n", path.c_str(), IMG_GetError() );
	}
	else
	{
		//Convert surface to screen format
		optimizedSurface = SDL_ConvertSurface( loadedSurface, gScreenSurface->format, NULL );
		if( optimizedSurface == NULL )
		{
			printf( "Unable to optimize image %s! SDL Error: %s\n", path.c_str(), SDL_GetError() );
		}
 
		//Get rid of old loaded surface
		SDL_FreeSurface( loadedSurface );
	}
 
	return optimizedSurface;
}
 
int main( int argc, char* args[] )
{
	//Start up SDL and create window
	if( !init() )
	{
		printf( "Failed to initialize!\n" );
	}
	else
	{
		//Load media
		if( !loadMedia() )
		{
			printf( "Failed to load media!\n" );
		}
		else
		{
			//Main loop flag
			bool quit = false;
 
			//Event handler
			SDL_Event e;
 
			//While application is running
			while( !quit )
			{
				//Handle events on queue
				while( SDL_PollEvent( &e ) != 0 )
				{
					//User requests quit
					if( e.type == SDL_QUIT )
					{
						quit = true;
					}
				}
 
				//Apply the PNG image
				SDL_BlitSurface( gPNGSurface, NULL, gScreenSurface, NULL );
 
				//Update the surface
				SDL_UpdateWindowSurface( gWindow );
			}
		}
	}
 
	//Free resources and close SDL
	close();
 
	return 0;
}

Merci de me mettre sur la voie

[LittleWhite]

Bonjour,

Le SDL_ConvertSurface a tendance à enlevé la transparence. Pouvez vous tester sans ?

[guitz]

Merci LittleWhite.

mais en fait j'ai pu utiliser du png-8 au lieu de png-24 avec mon code. Bon la qualité est pas extra, mais en phase de dev pour le moment ça convient

Bonne soirée