overf10w / sdl_test Goto Github PK

1. To install SDL on ubuntu machine:
    sudo apt-get install libsdl2-dev

2. Include it to main.cpp as #include "SDL.h"

3. To compile main.cpp file:
    g++ main.cpp `pkg-config --cflags --libs sdl2`


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>What is `pkg config`?

>So, how the SDL "main loop" works?
First, the guy looks at the API docs: API by category->Input events->event handling. 
From there, we read that in sdl all the events waiting to be handled are located in an event queue. 
Using SDL_PollEvent(returns 1 if there is pending event), SDL_PeepEvents() and SDL_WaitEvent() 
we can observe and handle waiting input events. Thus, main game (event) loop looks smth like this:

while (1) {
     SDL_Event event;
     while(SDL_PollEvent(&event)) {
          // handle your events here
     }
     // do some other stuff here -- draw your app, etc
}

>How colors are stored in SDL?
As Uint32.
To create color use this function: 
Uint32 SDL_MapRGB(const SDL_PixelFormat* format, Uint8 r, Uint8 g, Uint8 b);

>What is SDL_PixelFormat?

>How to change the surface color?
SDL_FillRect(screen, NULL, white);... but, don't forget to UPDATE the screen. If you change color 
but don't update screen, no visible changes will take place!

>why i don't see any changes when I change rect color?
Use update() function: int SDL_UpdateWindowSurface(SDL_Window* window); this function is equivalent 
to the SDL's 1.2 SDL_Flip()

>Limiting frames per second