[SDL3.2] cliprect.c example and SDL_lroundf

Mathias · April 9, 2025, 2:42pm

Isn’t that a more elegant solution if SDL_lroundf is already available?

Lines 89

//    const SDL_Rect cliprect = { (int) SDL_roundf(cliprect_position.x), (int) SDL_roundf(cliprect_position.y), CLIPRECT_SIZE, CLIPRECT_SIZE };
    const SDL_Rect cliprect = { SDL_lroundf(cliprect_position.x), SDL_lroundf(cliprect_position.y), CLIPRECT_SIZE, CLIPRECT_SIZE };

github.com/libsdl-org/SDL

examples/renderer/15-cliprect/cliprect.c

main

/*
 * This example creates an SDL window and renderer, and then draws a scene
 * to it every frame, while sliding around a clipping rectangle.
 *
 * This code is public domain. Feel free to use it for any purpose!
 */

#define SDL_MAIN_USE_CALLBACKS 1  /* use the callbacks instead of main() */
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 480
#define CLIPRECT_SIZE 250
#define CLIPRECT_SPEED 200   /* pixels per second */

/* We will use this renderer to draw into this window every frame. */
static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;
static SDL_Texture *texture = NULL;

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Peter87 · April 9, 2025, 4:33pm

Using SDL_lroundf in this situation would involve an implicit conversion from long to int.

Mathias · April 10, 2025, 3:14pm

If I understand correctly, SDL_lroundf varies depending on the system to 32 or 64bit long?

A long is 32-bit or 64-bit, depending on the system.