Created
August 23, 2012 08:47
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Draw an Image with SDL2
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#include <stdio.h> | |
#include <SDL2/SDL.h> | |
#include <SDL2/SDL_image.h> | |
#define WIDTH 800 | |
#define HEIGHT 600 | |
#define IMG_PATH "exit.png" | |
int main (int argc, char *argv[]) { | |
// variable declarations | |
SDL_Window *win = NULL; | |
SDL_Renderer *renderer = NULL; | |
SDL_Texture *img = NULL; | |
int w, h; // texture width & height | |
// Initialize SDL. | |
if (SDL_Init(SDL_INIT_VIDEO) < 0) | |
return 1; | |
// create the window and renderer | |
// note that the renderer is accelerated | |
win = SDL_CreateWindow("Image Loading", 100, 100, WIDTH, HEIGHT, 0); | |
renderer = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED); | |
// load our image | |
img = IMG_LoadTexture(renderer, IMG_PATH); | |
SDL_QueryTexture(img, NULL, NULL, &w, &h); // get the width and height of the texture | |
// put the location where we want the texture to be drawn into a rectangle | |
// I'm also scaling the texture 2x simply by setting the width and height | |
SDL_Rect texr; texr.x = WIDTH/2; texr.y = HEIGHT/2; texr.w = w*2; texr.h = h*2; | |
// main loop | |
while (1) { | |
// event handling | |
SDL_Event e; | |
if ( SDL_PollEvent(&e) ) { | |
if (e.type == SDL_QUIT) | |
break; | |
else if (e.type == SDL_KEYUP && e.key.keysym.sym == SDLK_ESCAPE) | |
break; | |
} | |
// clear the screen | |
SDL_RenderClear(renderer); | |
// copy the texture to the rendering context | |
SDL_RenderCopy(renderer, img, NULL, &texr); | |
// flip the backbuffer | |
// this means that everything that we prepared behind the screens is actually shown | |
SDL_RenderPresent(renderer); | |
} | |
SDL_DestroyTexture(img); | |
SDL_DestroyRenderer(renderer); | |
SDL_DestroyWindow(win); | |
return 0; | |
} |
WaitEvent, waits for events, which is more for applications than games, because if you use it in a game, the entire game would hang until it gets an event, so there is no definitive option, hence you can choose
the CPU of the example can be very easly bypassed while still using poll events, just add an SDL_Delay
best also to explain that if someone were to make a game using this, that itd be best to use PollEvents with a frame-limiter/vsync
i love you
gay
How the heck is he or even she gay by loving someone??
Damn, why are all those people still here. Bros need to get a life.
Go contribute to some open-source projects!
i love you
gay
How the heck is he or even she gay by loving someone??
i was joking
very funny
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IMHO, the gist is good once you apply the changes I suggested. The code will remain short because this is mainly updating few lines of the existing code. In the detail:
SDL_rect
) is cosmetic. Without doing this, the image is in general not centeredSDL_WaitEvent
) is very important. If you useSDL_PollEvent
, the program uses 100% CPU (because it permanently refreshes the displayed image, which is useless). With the change I suggest, this problem disappearsSDL_FreeSurface
) is recommended because otherwise you might have a memory leak as you don't destroy the object.