How to check if renderer is not empty?

Question

I have a SDL_Renderer in SDL2 that I use both to render textures on screen and to render textures on textures, my problem is that when I render to texture the renderer may have some content in it which needs to be drawn, but if it's empty and I call SDL_RenderPresent() on it the screen flickers. So how can I check if there's something drawn inside the renderer?

Answer 1

Ok, so from what I understood, when you are rendering to a texture there's no need to flush the renderer before, not even after; that's why there isn't such function to check if the renderer is empty or not.

So the steps are these:

// This draws inside the renderer's buffer
SDL_RenderCopy(renderer, texture, source, bounds);
// This switches to rendering on texture
SDL_SetRenderTarget(renderer, target_texture);
// Apparently this is enough to draw on the texture (so there's no buffer I guess?)
SDL_RenderCopy(renderer, texture2, source, bounds);
// This switches to rendering on renderer buffer
SDL_SetRenderTarget(renderer, NULL);
// This flushes the renderer buffer (so only the SDL_RenderCopy() before rendering on texture)
SDL_RenderPresent(renderer);

See my other question for this.