Difference between surface and texture (SDL / general)

Question

Can anyone explain to me in simple words what is the difference between texture and surface? I saw it used in SDL2 as SDL_Surface and SDL_Tex

Answer 1

SDL_Texture is loaded in your video card's VRAM instead of regular RAM.

Answer 2

Basically your assumption "has to do something with GPU?" is right.

SDL_Surface is used in software rendering. With software rendering, as saloomi2012 correctly noticed, you are using regular RAM to store image data. Thus, in most cases you can access data buffer associated with surface directly, modifying its content, i.e. it is using CPU, hence the software name.

SDL_Texture on the other hand, is used in a hardware rendering, textures are stored in VRAM and you don't have access to it directly as with SDL_Surface. The rendering operations are accelerated by GPU, using, internally, either OpenGL or DirectX (available only on Windows) API, which in turn are using your video hardware, hence hardware rendering name.

Needless to say that hardware rendering is by orders of magnitude faster than software rendering and should be always be considered as primary option.

Answer 3

There is more information about that in:

https://thenumbat.github.io/cpp-course/sdl2/05/05.html

As mentioned in the last lesson, textures are the GPU rendering equivalent of surfaces. Hence, textures are almost always created from surfaces, using the function SDL_CreateTextureFromSurface(). This function more or less does what you'd expect—the parameters are the rendering context and a surface to create the texture from. As with other creation functions, it will return NULL on failure.

I hope it helps you!

Answer 4

Surfaces use your RAM and Textures use your video card that is more fast than the surfaces.