>>103028403
With that you mean displaying the SDL_Surface or the SDL_Texture? For the latter, you have to do
SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
The reason for no blending by default is that SDL supports multiple backends and not all of them are hardware accelerated. With hardware acceleration it doesn't matter because every pixel runs in parallel so blending will be just as fast as no blending. But for software rendering you really shouldn't use blending if you don't need it because the number of CPU cycles is multiplied by 20 or so, not counting the memory access delay. And even if you use it, you probably don't have half-transparent pixels, just visible and invisible ones so blending is overkill