How to render SDL2 texture into GTK3+ window?

Question

I am creating a music player and trying to use GTK3+ for creating user interface. I am using SDL_CreateWindowFrom function to let SDL2 use GTK3+ window rather than creating one but cann't figure out the steps I need to follow in order to render the SDL2 textures into GTK3+ window.

Code getting GTK3 window ID

window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "---");
gtk_widget_show(window);
gdkWin = gtk_widget_get_window(GTK_WIDGET(window));
data->playContext->winID = GDK_WINDOW_XID(gdkWin);
gtk_main();

Code Setting SDL2 window

playContext->display->window = SDL_CreateWindowFrom((const void *)playContext->winID);
playContext->display->renderer = SDL_CreateRenderer(playContext->display->window, -1, playContext->display->render_flags);

Code Rendering SDL2 textures

SDL_RenderClear(playContext->display->renderer);
SDL_RenderCopy(playContext->display->renderer, playContext->textureQ.head->bmp, NULL, NULL);
SDL_RenderPresent(playContext->display->renderer);

You should post minimal example illustrating what you've attempted so far and what you're trying to achieve. It is very hard to see what you're doing without the code, the only thing I could say is that there is no SDL_WINDOWID in SDL2, so setting it cannot have any effect at all. You should use SDL_CreateWindowFrom, as shown in tests/testnative.c in SDL sources, but using it with opengl is kind of tricky. — keltar
Oops, SDL_WINDOWID got stuck in my mind after doing a lot of searching — Asit Rout

keltar keltar · Accepted Answer · 2017-11-15T14:48:05

Since example you put is effectively incomplete even on most important bits (e.g. renderer creation flags), and you don't specify which part gives you a problem, here is my example (which, on my system, works on both gtk2 and gtk3 - I wouldn't vouch it is completely fine though):

#include <stdio.h>
#include <gtk/gtk.h>
#include <gdk/gdkx.h>
#include <SDL.h>
#include <stdbool.h>

static SDL_Window *sdl_window;
static SDL_Renderer *sdl_renderer;
static SDL_Surface *sdl_surface;
static GtkWindow *gtk_window;
static GtkWidget *gtk_da;
static void *gdk_window;
static void *window_id;

static gboolean idle(void *ud) {
    (void)ud;
    if(!sdl_window) {
        printf("creating SDL window for window id %p\n", window_id);
        sdl_window = SDL_CreateWindowFrom(window_id);
        printf("sdl_window=%p\n", sdl_window);
        if(!sdl_window) {
            printf("%s\n", SDL_GetError());
        }
        sdl_renderer = SDL_CreateRenderer(sdl_window, -1, 0);
        printf("sdl_renderer=%p\n", sdl_renderer);
        if(!sdl_renderer) {
            printf("%s\n", SDL_GetError());
        }
    } else {
        SDL_SetRenderDrawColor(sdl_renderer, 255, 0, 0, 255);
        SDL_RenderClear(sdl_renderer);
        SDL_RenderPresent(sdl_renderer);
    }
    return true;
}

int main(int argc, char **argv) {
    gtk_init(&argc, &argv);
    gtk_window = (GtkWindow*)gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title(gtk_window, "test");

    gtk_da = gtk_drawing_area_new();
    gtk_container_add(GTK_CONTAINER(gtk_window), gtk_da);
    gtk_widget_show_all(GTK_WIDGET(gtk_window));

    gdk_window = gtk_widget_get_window(GTK_WIDGET(gtk_da));
    window_id = (void*)(intptr_t)GDK_WINDOW_XID(gdk_window);

    SDL_Init(SDL_INIT_VIDEO);

    g_idle_add(&idle, 0);
    gtk_main();
    return 0;
}

How to render SDL2 texture into GTK3+ window?

1 Answers