Commit 86720b01 authored by Emmanuele Bassi's avatar Emmanuele Bassi

docs: Add initialization example for GtkGLArea

Show how to safely check for errors when initializing the OpenGL
pipeline.
parent d79bc003
......@@ -91,7 +91,46 @@
*
* If you need to initialize OpenGL state, e.g. buffer objects or
* shaders, you should use the #GtkWidget::realize signal; you
* can use the #GtkWidget::unrealize signal to clean up.
* can use the #GtkWidget::unrealize signal to clean up. Since the
* #GdkGLContext creation and initialization may fail, you will
* need to check for errors, using gtk_gl_area_get_error(). An example
* of how to safely initialize the GL state is:
*
* |[<!-- language="C" -->
* static void
* on_realize (GtkGLarea *area)
* {
* // We need to make the context current if we want to
* // call GL API
* gtk_gl_area_make_current (area);
*
* // If there were errors during the initialization or
* // when trying to make the context current, this
* // function will return a #GError for you to catch
* if (gtk_gl_area_get_error (area) != NULL)
* return;
*
* // You can also use gtk_gl_area_set_error() in order
* // to show eventual initialization errors on the
* // GtkGLArea widget itself
* GError *internal_error = NULL;
* init_buffer_objects (&error);
* if (error != NULL)
* {
* gtk_gl_area_set_error (area, error);
* g_error_free (error);
* return;
* }
*
* init_shaders (&error);
* if (error != NULL)
* {
* gtk_gl_area_set_error (area, error);
* g_error_free (error);
* return;
* }
* }
* ]|
*
* If you need to change the options for creating the #GdkGLContext
* you should use the #GtkGLArea::create-context signal.
......
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