SDL2: Renderer vs Surface

In SDL2, SDL_Renderer and SDL_Surface are two different ways to render graphics, each with its own use cases and advantages.

SDL_Surface

An SDL_Surface is a pixel buffer that represents an image in memory. It contains the pixel data and format information. You can manipulate the pixels directly and perform software-based rendering using an SDL_Surface.

Here's an example of creating an SDL_Surface and filling it with a solid color:

1SDL_Surface* surface{SDL_CreateRGBSurface(
2  0, width, height, 32, 0, 0, 0, 0)};
3
4SDL_FillRect(surface, nullptr, SDL_MapRGB(
5  surface->format, 255, 0, 0));

SDL_Renderer

An SDL_Renderer is a rendering context that provides hardware-accelerated 2D rendering. It abstracts the rendering process and allows you to draw primitives, textures, and perform transformations efficiently.

Here's an example of creating an SDL_Renderer and drawing a rectangle:

1SDL_Renderer* renderer{SDL_CreateRenderer(
2  window, -1, 0)};
3SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
4SDL_RenderClear(renderer);
5SDL_Rect rect = {100, 100, 200, 150};
6SDL_RenderFillRect(renderer, &rect);
7SDL_RenderPresent(renderer);

Differences and Use Cases

• SDL_Surface is suitable for software rendering and direct pixel manipulation, while SDL_Renderer provides hardware-accelerated rendering.
• SDL_Surface is generally slower for rendering compared to SDL_Renderer but offers more low-level control over pixels.
• SDL_Renderer is preferred for efficient rendering of complex graphics, such as textures, primitives, and transformations.
• SDL_Surface can be converted to a texture using SDL_CreateTextureFromSurface for rendering with an SDL_Renderer.

In most cases, using SDL_Renderer is recommended for better performance and modern rendering techniques. However, SDL_Surface is still useful for specific tasks like pixel-level manipulations or software-based rendering algorithms.