SDL (Simple DirectMedia Layer)/Graphics/Rendering surfaces

In this section, we will modify our code to optimise SDL_Surface blitting using SDL_ConvertSurface and stretch our image to fullscreen using SDL_BlitScaled. You can download the source code of this section in this GitLab repository. All source code is stored in this group. Optimising a SDL_Surface for blitting We can optimise a SDL_Surface for blitting, which in turn improves performance. SDL_ConvertSurface is used to optimize images for faster repeat blitting. This is accomplished by converting the original and storing the result as a new surface. We'll update our wb_loadImage function by using the following code. /* Set temporary SDL_Surface */ SDL_Surface *temp = NULL; /* Load the image from its file path to a SDL_Surface */ temp = IMG_Load(WB_IMAGE_PATH); if (temp == NULL) { fprintf(stderr, "WikiBook failed to load image: %s\n", IMG_GetError()); return -1; } /* Optimise SDL_Surface for blitting */ wb->image = SDL_ConvertSurface(temp, wb->screen->format, 0); /* Destroy temporary SDL_Surface */ SDL_FreeSurface(temp); Remember to destroy SDL object pointers using their corresponding functions, in this case SDL_FreeSurface. Blitting a SDL_Surface to fullscreen We'll replace SDL_BlitSurface with SDL_BlitScaled. We'll write a static (and therefore private) function that blits a surface to fullscreen. /* Maximise surface to full screen */ static int setSurfaceFullScreen(SDL_Surface *surface, SDL_Surface *screen) { /* Create SDL_Rect to full screen */ SDL_Rect rt = { 0, 0, WB_WIDTH, WB_HEIGHT }; /* Blit SDL_Surface to the size of SDL_Rect */ if (SDL_BlitScaled(surface, NULL, screen, &rt) < 0) { fprintf(stderr, "Failed to set surface to full screen: %s\n", SDL_GetError()); return -1; } return 0; } We'll have to initialise and declare a SDL_Rect with the size of the entire window and blit the surface using dimensions of that SDL_Rect. We replace the blitting function in our wb_loadImage: /* Blit SDL_Surface to full screen */ if (setSurfaceFullScreen(wb->image, wb->screen) < 0) { return -1; } You'll notice that we're not declaring a SDL_Rect pointer, it's a relatively small structure compared to SDL_Surface and the like, so we don't have to dynamically allocate memory for it. . -