Put the render loop back in its right place, but with delaying functionality...

Put the render loop back in its right place, but with delaying functionality to keep it down to roughly 60fps, not eating up all the X11 time.

test/testshape.c

@@ -6,11 +6,14 @@
 #include <SDL_video.h>
 #include <SDL_shape.h>
 #include <SDL_keysym.h>
+#include <SDL_timer.h>
 
 #define SHAPED_WINDOW_X 150
 #define SHAPED_WINDOW_Y 150
 #define SHAPED_WINDOW_DIMENSION 640
 
+#define TICK_INTERVAL 18
+
 void render(SDL_Window* window,SDL_Texture *texture,SDL_Rect texture_dimensions) {
 	SDL_SelectRenderer(window);
 	
@@ -24,6 +27,16 @@ void render(SDL_Window* window,SDL_Texture *texture,SDL_Rect texture_dimensions)
 	SDL_RenderPresent();
 }
 
+static Uint32 next_time;
+
+Uint32 time_left() {
+	Uint32 now = SDL_GetTicks();
+	if(next_time <= now)
+		return 0;
+	else
+		return next_time - now;
+}
+
 int main(int argc,char** argv) {
         if(argc < 2) {
         	printf("SDL_Shape requires at least one bitmap file as argument.\n");
@@ -106,7 +119,7 @@ int main(int argc,char** argv) {
 	SDL_QueryTexture(textures[current_picture],&format,&access,&texture_dimensions.w,&texture_dimensions.h);
 	SDL_SetWindowSize(window,texture_dimensions.w,texture_dimensions.h);
 	SDL_SetWindowShape(window,pictures[current_picture],&mode);
-	render(window,textures[current_picture],texture_dimensions);
+	next_time = SDL_GetTicks() + TICK_INTERVAL;
 	while(should_exit == 0) {
 		event_pending = SDL_PollEvent(&event);
 		if(event_pending == 1) {
@@ -123,13 +136,14 @@ int main(int argc,char** argv) {
 				SDL_QueryTexture(textures[current_picture],&format,&access,&texture_dimensions.w,&texture_dimensions.h);
 				SDL_SetWindowSize(window,texture_dimensions.w,texture_dimensions.h);
 				SDL_SetWindowShape(window,pictures[current_picture],&mode);
-				render(window,textures[current_picture],texture_dimensions);
-				
 			}
 			if(event.type == SDL_QUIT)
 				should_exit = 1;
 			event_pending = 0;
 		}
+		render(window,textures[current_picture],texture_dimensions);
+		SDL_Delay(time_left());
+		next_time += TICK_INTERVAL;
 	}
 	
 	//Free the textures.