/* GDK - The GIMP Drawing Kit * * gdkglcontext.c: GL context abstraction * * Copyright © 2014 Emmanuele Bassi * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library. If not, see . */ /** * GdkGLContext: * * `GdkGLContext` is an object representing a platform-specific * OpenGL draw context. * * `GdkGLContext`s are created for a surface using * [method@Gdk.Surface.create_gl_context], and the context will match * the characteristics of the surface. * * A `GdkGLContext` is not tied to any particular normal framebuffer. * For instance, it cannot draw to the surface back buffer. The GDK * repaint system is in full control of the painting to that. Instead, * you can create render buffers or textures and use [func@cairo_draw_from_gl] * in the draw function of your widget to draw them. Then GDK will handle * the integration of your rendering with that of other widgets. * * Support for `GdkGLContext` is platform-specific and context creation * can fail, returning %NULL context. * * A `GdkGLContext` has to be made "current" in order to start using * it, otherwise any OpenGL call will be ignored. * * ## Creating a new OpenGL context * * In order to create a new `GdkGLContext` instance you need a `GdkSurface`, * which you typically get during the realize call of a widget. * * A `GdkGLContext` is not realized until either [method@Gdk.GLContext.make_current] * or [method@Gdk.GLContext.realize] is called. It is possible to specify * details of the GL context like the OpenGL version to be used, or whether * the GL context should have extra state validation enabled after calling * [method@Gdk.Surface.create_gl_context] by calling [method@Gdk.GLContext.realize]. * If the realization fails you have the option to change the settings of * the `GdkGLContext` and try again. * * ## Using a GdkGLContext * * You will need to make the `GdkGLContext` the current context before issuing * OpenGL calls; the system sends OpenGL commands to whichever context is current. * It is possible to have multiple contexts, so you always need to ensure that * the one which you want to draw with is the current one before issuing commands: * * ```c * gdk_gl_context_make_current (context); * ``` * * You can now perform your drawing using OpenGL commands. * * You can check which `GdkGLContext` is the current one by using * [func@Gdk.GLContext.get_current]; you can also unset any `GdkGLContext` * that is currently set by calling [func@Gdk.GLContext.clear_current]. */ #include "config.h" #include "gdkglcontextprivate.h" #include "gdkdebug.h" #include "gdkdisplayprivate.h" #include "gdkintl.h" #include "gdkmemoryformatprivate.h" #include "gdkmemorytextureprivate.h" #include "gdkprofilerprivate.h" #include "gdk-private.h" #ifdef GDK_WINDOWING_WIN32 # include "gdk/win32/gdkwin32.h" #endif #include #ifdef HAVE_EGL #include #endif #define DEFAULT_ALLOWED_APIS GDK_GL_API_GL | GDK_GL_API_GLES typedef struct { int major; int minor; int gl_version; guint has_khr_debug : 1; guint use_khr_debug : 1; guint has_unpack_subimage : 1; guint has_debug_output : 1; guint extensions_checked : 1; guint debug_enabled : 1; guint forward_compatible : 1; guint is_legacy : 1; GdkGLAPI allowed_apis; GdkGLAPI api; int max_debug_label_length; #ifdef HAVE_EGL EGLContext egl_context; #endif } GdkGLContextPrivate; enum { PROP_0, PROP_ALLOWED_APIS, PROP_API, PROP_SHARED_CONTEXT, LAST_PROP }; static GParamSpec *properties[LAST_PROP] = { NULL, }; G_DEFINE_QUARK (gdk-gl-error-quark, gdk_gl_error) G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GdkGLContext, gdk_gl_context, GDK_TYPE_DRAW_CONTEXT) typedef struct _MaskedContext MaskedContext; static inline MaskedContext * mask_context (GdkGLContext *context, gboolean surfaceless) { return (MaskedContext *) GSIZE_TO_POINTER (GPOINTER_TO_SIZE (context) | (surfaceless ? 1 : 0)); } static inline GdkGLContext * unmask_context (MaskedContext *mask) { return GDK_GL_CONTEXT (GSIZE_TO_POINTER (GPOINTER_TO_SIZE (mask) & ~(gsize) 1)); } static void unref_unmasked (gpointer data) { g_object_unref (unmask_context (data)); } static GPrivate thread_current_context = G_PRIVATE_INIT (unref_unmasked); static void gdk_gl_context_clear_old_updated_area (GdkGLContext *context) { int i; for (i = 0; i < 2; i++) { g_clear_pointer (&context->old_updated_area[i], cairo_region_destroy); } } static void gdk_gl_context_dispose (GObject *gobject) { GdkGLContext *context = GDK_GL_CONTEXT (gobject); #ifdef HAVE_EGL GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); if (priv->egl_context != NULL) { GdkSurface *surface = gdk_gl_context_get_surface (context); GdkDisplay *display = gdk_surface_get_display (surface); EGLDisplay *egl_display = gdk_display_get_egl_display (display); if (eglGetCurrentContext () == priv->egl_context) eglMakeCurrent(egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT); GDK_DISPLAY_NOTE (display, OPENGL, g_message ("Destroying EGL context")); eglDestroyContext (egl_display, priv->egl_context); priv->egl_context = NULL; } #endif gdk_gl_context_clear_old_updated_area (context); G_OBJECT_CLASS (gdk_gl_context_parent_class)->dispose (gobject); } static void gdk_gl_context_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec) { GdkGLContext *self = GDK_GL_CONTEXT (object); switch (prop_id) { case PROP_ALLOWED_APIS: gdk_gl_context_set_allowed_apis (self, g_value_get_flags (value)); break; case PROP_SHARED_CONTEXT: g_assert (g_value_get_object (value) == NULL); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); } } static void gdk_gl_context_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec) { GdkGLContext *self = GDK_GL_CONTEXT (object); GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); switch (prop_id) { case PROP_ALLOWED_APIS: g_value_set_flags (value, priv->allowed_apis); break; case PROP_API: g_value_set_flags (value, priv->api); break; case PROP_SHARED_CONTEXT: g_value_set_object (value, NULL); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); } } #define N_EGL_ATTRS 16 static GdkGLAPI gdk_gl_context_real_realize (GdkGLContext *context, GError **error) { #ifdef HAVE_EGL GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); GdkDisplay *display = gdk_gl_context_get_display (context); EGLDisplay egl_display = gdk_display_get_egl_display (display); if (egl_display) { EGLConfig egl_config; GdkGLContext *share = gdk_display_get_gl_context (display); GdkGLContextPrivate *share_priv = gdk_gl_context_get_instance_private (share); EGLContext ctx; EGLint context_attribs[N_EGL_ATTRS]; int major, minor, flags; gboolean debug_bit, forward_bit, legacy_bit; GdkGLAPI api; int i = 0; G_GNUC_UNUSED gint64 start_time = GDK_PROFILER_CURRENT_TIME; gdk_gl_context_get_required_version (context, &major, &minor); debug_bit = gdk_gl_context_get_debug_enabled (context); forward_bit = gdk_gl_context_get_forward_compatible (context); legacy_bit = GDK_DISPLAY_DEBUG_CHECK (display, GL_LEGACY) || (share != NULL && gdk_gl_context_is_legacy (share)); if (display->have_egl_no_config_context) egl_config = NULL; else egl_config = gdk_display_get_egl_config (display); flags = 0; if (debug_bit) flags |= EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR; if (forward_bit) flags |= EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR; if (gdk_gl_context_is_api_allowed (context, GDK_GL_API_GL, NULL) && eglBindAPI (EGL_OPENGL_API)) { /* We want a core profile, unless in legacy mode */ context_attribs[i++] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR; context_attribs[i++] = legacy_bit ? EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR : EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR; /* Specify the version */ context_attribs[i++] = EGL_CONTEXT_MAJOR_VERSION_KHR; context_attribs[i++] = legacy_bit ? 3 : major; context_attribs[i++] = EGL_CONTEXT_MINOR_VERSION_KHR; context_attribs[i++] = legacy_bit ? 0 : minor; api = GDK_GL_API_GL; } else if (gdk_gl_context_is_api_allowed (context, GDK_GL_API_GLES, NULL) && eglBindAPI (EGL_OPENGL_ES_API)) { context_attribs[i++] = EGL_CONTEXT_CLIENT_VERSION; if (major == 3) context_attribs[i++] = 3; else context_attribs[i++] = 2; api = GDK_GL_API_GLES; } else { g_set_error_literal (error, GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE, _("The EGL implementation does not support any allowed APIs")); return 0; } /* Specify the flags */ context_attribs[i++] = EGL_CONTEXT_FLAGS_KHR; context_attribs[i++] = flags; context_attribs[i++] = EGL_NONE; g_assert (i < N_EGL_ATTRS); GDK_DISPLAY_NOTE (display, OPENGL, g_message ("Creating EGL context version %d.%d (debug:%s, forward:%s, legacy:%s, es:%s)", major, minor, debug_bit ? "yes" : "no", forward_bit ? "yes" : "no", legacy_bit ? "yes" : "no", api == GDK_GL_API_GLES ? "yes" : "no")); ctx = eglCreateContext (egl_display, egl_config, share != NULL ? share_priv->egl_context : EGL_NO_CONTEXT, context_attribs); /* If context creation failed without the ES bit, let's try again with it */ if (ctx == NULL && gdk_gl_context_is_api_allowed (context, GDK_GL_API_GLES, NULL) && eglBindAPI (EGL_OPENGL_ES_API)) { i = 0; context_attribs[i++] = EGL_CONTEXT_MAJOR_VERSION; context_attribs[i++] = 2; context_attribs[i++] = EGL_CONTEXT_MINOR_VERSION; context_attribs[i++] = 0; context_attribs[i++] = EGL_CONTEXT_FLAGS_KHR; context_attribs[i++] = flags & ~EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR; context_attribs[i++] = EGL_NONE; g_assert (i < N_EGL_ATTRS); legacy_bit = FALSE; api = GDK_GL_API_GLES; GDK_DISPLAY_NOTE (display, OPENGL, g_message ("eglCreateContext failed, switching to OpenGL ES")); ctx = eglCreateContext (egl_display, egl_config, share != NULL ? share_priv->egl_context : EGL_NO_CONTEXT, context_attribs); } /* If context creation failed without the legacy bit, let's try again with it */ if (ctx == NULL && gdk_gl_context_is_api_allowed (context, GDK_GL_API_GL, NULL) && eglBindAPI (EGL_OPENGL_API)) { i = 0; context_attribs[i++] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR; context_attribs[i++] = EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR; context_attribs[i++] = EGL_CONTEXT_MAJOR_VERSION; context_attribs[i++] = 3; context_attribs[i++] = EGL_CONTEXT_MINOR_VERSION; context_attribs[i++] = 0; context_attribs[i++] = EGL_CONTEXT_FLAGS_KHR; context_attribs[i++] = flags & ~EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR; context_attribs[i++] = EGL_NONE; g_assert (i < N_EGL_ATTRS); legacy_bit = TRUE; api = GDK_GL_API_GL; GDK_DISPLAY_NOTE (display, OPENGL, g_message ("eglCreateContext failed, switching to legacy")); ctx = eglCreateContext (egl_display, egl_config, share != NULL ? share_priv->egl_context : EGL_NO_CONTEXT, context_attribs); } if (ctx == NULL) { g_set_error_literal (error, GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE, _("Unable to create a GL context")); return 0; } GDK_DISPLAY_NOTE (display, OPENGL, g_message ("Created EGL context[%p]", ctx)); priv->egl_context = ctx; gdk_gl_context_set_is_legacy (context, legacy_bit); gdk_profiler_end_mark (start_time, "realize GdkWaylandGLContext", NULL); return api; } #endif g_set_error_literal (error, GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE, _("The current backend does not support OpenGL")); return 0; } #undef N_EGL_ATTRS static cairo_region_t * gdk_gl_context_real_get_damage (GdkGLContext *context) { GdkSurface *surface = gdk_draw_context_get_surface (GDK_DRAW_CONTEXT (context)); #ifdef HAVE_EGL GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); GdkDisplay *display = gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)); if (priv->egl_context && display->have_egl_buffer_age) { EGLSurface egl_surface; int buffer_age = 0; egl_surface = gdk_surface_get_egl_surface (surface); gdk_gl_context_make_current (context); eglQuerySurface (gdk_display_get_egl_display (display), egl_surface, EGL_BUFFER_AGE_EXT, &buffer_age); switch (buffer_age) { case 1: return cairo_region_create (); break; case 2: if (context->old_updated_area[0]) return cairo_region_copy (context->old_updated_area[0]); break; case 3: if (context->old_updated_area[0] && context->old_updated_area[1]) { cairo_region_t *damage = cairo_region_copy (context->old_updated_area[0]); cairo_region_union (damage, context->old_updated_area[1]); return damage; } break; default: ; } } #endif return cairo_region_create_rectangle (&(GdkRectangle) { 0, 0, gdk_surface_get_width (surface), gdk_surface_get_height (surface) }); } static gboolean gdk_gl_context_real_is_shared (GdkGLContext *self, GdkGLContext *other) { if (gdk_draw_context_get_display (GDK_DRAW_CONTEXT (self)) != gdk_draw_context_get_display (GDK_DRAW_CONTEXT (other))) return FALSE; /* XXX: Should we check es or legacy here? */ return TRUE; } static gboolean gdk_gl_context_real_clear_current (GdkGLContext *context) { GdkDisplay *display = gdk_gl_context_get_display (context); #ifdef HAVE_EGL GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); if (priv->egl_context == NULL) return FALSE; return eglMakeCurrent (gdk_display_get_egl_display (display), EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT); #else return FALSE; #endif } static gboolean gdk_gl_context_real_make_current (GdkGLContext *context, gboolean surfaceless) { #ifdef HAVE_EGL GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); GdkDisplay *display = gdk_gl_context_get_display (context); EGLSurface egl_surface; if (priv->egl_context == NULL) return FALSE; if (!surfaceless) egl_surface = gdk_surface_get_egl_surface (gdk_gl_context_get_surface (context)); else egl_surface = EGL_NO_SURFACE; return eglMakeCurrent (gdk_display_get_egl_display (display), egl_surface, egl_surface, priv->egl_context); #else return FALSE; #endif } static void gdk_gl_context_real_begin_frame (GdkDrawContext *draw_context, gboolean prefers_high_depth, cairo_region_t *region) { GdkGLContext *context = GDK_GL_CONTEXT (draw_context); G_GNUC_UNUSED GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); GdkSurface *surface; cairo_region_t *damage; int ww, wh; surface = gdk_draw_context_get_surface (draw_context); #ifdef HAVE_EGL if (priv->egl_context) gdk_surface_ensure_egl_surface (surface, prefers_high_depth); #endif damage = GDK_GL_CONTEXT_GET_CLASS (context)->get_damage (context); if (context->old_updated_area[1]) cairo_region_destroy (context->old_updated_area[1]); context->old_updated_area[1] = context->old_updated_area[0]; context->old_updated_area[0] = cairo_region_copy (region); cairo_region_union (region, damage); cairo_region_destroy (damage); ww = gdk_surface_get_width (surface) * gdk_surface_get_scale_factor (surface); wh = gdk_surface_get_height (surface) * gdk_surface_get_scale_factor (surface); gdk_gl_context_make_current (context); /* Initial setup */ glClearColor (0.0f, 0.0f, 0.0f, 0.0f); glDisable (GL_DEPTH_TEST); glDisable (GL_BLEND); glBlendFunc (GL_ONE, GL_ONE_MINUS_SRC_ALPHA); glViewport (0, 0, ww, wh); #ifdef HAVE_EGL if (priv->egl_context) glDrawBuffers (1, (GLenum[1]) { GL_BACK_LEFT }); #endif } static void gdk_gl_context_real_end_frame (GdkDrawContext *draw_context, cairo_region_t *painted) { #ifdef HAVE_EGL GdkGLContext *context = GDK_GL_CONTEXT (draw_context); GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); GdkSurface *surface = gdk_gl_context_get_surface (context); GdkDisplay *display = gdk_surface_get_display (surface); EGLSurface egl_surface; if (priv->egl_context == NULL) return; gdk_gl_context_make_current (context); egl_surface = gdk_surface_get_egl_surface (surface); gdk_profiler_add_mark (GDK_PROFILER_CURRENT_TIME, 0, "EGL", "swap buffers"); if (display->have_egl_swap_buffers_with_damage) { EGLint stack_rects[4 * 4]; /* 4 rects */ EGLint *heap_rects = NULL; int i, j, n_rects = cairo_region_num_rectangles (painted); int surface_height = gdk_surface_get_height (surface); int scale = gdk_surface_get_scale_factor (surface); EGLint *rects; if (n_rects < G_N_ELEMENTS (stack_rects) / 4) rects = (EGLint *)&stack_rects; else heap_rects = rects = g_new (EGLint, n_rects * 4); for (i = 0, j = 0; i < n_rects; i++) { cairo_rectangle_int_t rect; cairo_region_get_rectangle (painted, i, &rect); rects[j++] = rect.x * scale; rects[j++] = (surface_height - rect.height - rect.y) * scale; rects[j++] = rect.width * scale; rects[j++] = rect.height * scale; } eglSwapBuffersWithDamageEXT (gdk_display_get_egl_display (display), egl_surface, rects, n_rects); g_free (heap_rects); } else eglSwapBuffers (gdk_display_get_egl_display (display), egl_surface); #endif } static void gdk_gl_context_surface_resized (GdkDrawContext *draw_context) { GdkGLContext *context = GDK_GL_CONTEXT (draw_context); gdk_gl_context_clear_old_updated_area (context); } static void gdk_gl_context_class_init (GdkGLContextClass *klass) { GObjectClass *gobject_class = G_OBJECT_CLASS (klass); GdkDrawContextClass *draw_context_class = GDK_DRAW_CONTEXT_CLASS (klass); klass->realize = gdk_gl_context_real_realize; klass->get_damage = gdk_gl_context_real_get_damage; klass->is_shared = gdk_gl_context_real_is_shared; klass->make_current = gdk_gl_context_real_make_current; klass->clear_current = gdk_gl_context_real_clear_current; draw_context_class->begin_frame = gdk_gl_context_real_begin_frame; draw_context_class->end_frame = gdk_gl_context_real_end_frame; draw_context_class->surface_resized = gdk_gl_context_surface_resized; /** * GdkGLContext:shared-context: (attributes org.gtk.Property.get=gdk_gl_context_get_shared_context) * * Always %NULL * * As many contexts can share data now and no single shared context exists * anymore, this function has been deprecated and now always returns %NULL. * * Deprecated: 4.4: Use [method@Gdk.GLContext.is_shared] to check if contexts * can be shared. */ properties[PROP_SHARED_CONTEXT] = g_param_spec_object ("shared-context", P_("Shared context"), P_("The GL context this context shares data with"), GDK_TYPE_GL_CONTEXT, G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS | G_PARAM_DEPRECATED); /** * GdkGLContext:allowed-apis: (attributes org.gtk.Property.get=gdk_gl_context_get_allowed_apis org.gtk.Property.gdk_gl_context_set_allowed_apis) * * The allowed APIs. * * Since: 4.6 */ properties[PROP_ALLOWED_APIS] = g_param_spec_flags ("allowed-apis", P_("Allowed APIs"), P_("The list of allowed APIs for this context"), GDK_TYPE_GL_API, DEFAULT_ALLOWED_APIS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY); /** * GdkGLContext:api: (attributes org.gtk.Property.get=gdk_gl_context_get_api) * * The API currently in use. * * Since: 4.6 */ properties[PROP_API] = g_param_spec_flags ("api", P_("API"), P_("The API currently in use"), GDK_TYPE_GL_API, 0, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY); gobject_class->set_property = gdk_gl_context_set_property; gobject_class->get_property = gdk_gl_context_get_property; gobject_class->dispose = gdk_gl_context_dispose; g_object_class_install_properties (gobject_class, LAST_PROP, properties); } static void gdk_gl_context_init (GdkGLContext *self) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); priv->allowed_apis = DEFAULT_ALLOWED_APIS; } /* Must have called gdk_display_prepare_gl() before */ GdkGLContext * gdk_gl_context_new (GdkDisplay *display, GdkSurface *surface) { GdkGLContext *shared; g_assert (surface == NULL || display == gdk_surface_get_display (surface)); /* assert gdk_display_prepare_gl() had been called */ shared = gdk_display_get_gl_context (display); g_assert (shared); return g_object_new (G_OBJECT_TYPE (shared), "display", display, "surface", surface, NULL); } void gdk_gl_context_push_debug_group (GdkGLContext *context, const char *message) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); if (priv->use_khr_debug) glPushDebugGroupKHR (GL_DEBUG_SOURCE_APPLICATION, 0, -1, message); } void gdk_gl_context_push_debug_group_printf (GdkGLContext *context, const char *format, ...) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); char *message; va_list args; if (priv->use_khr_debug) { int msg_len; va_start (args, format); message = g_strdup_vprintf (format, args); va_end (args); msg_len = MIN (priv->max_debug_label_length, strlen (message) - 1); glPushDebugGroupKHR (GL_DEBUG_SOURCE_APPLICATION, 0, msg_len, message); g_free (message); } } void gdk_gl_context_pop_debug_group (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); if (priv->use_khr_debug) glPopDebugGroupKHR (); } void gdk_gl_context_label_object (GdkGLContext *context, guint identifier, guint name, const char *label) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); if (priv->use_khr_debug) glObjectLabel (identifier, name, -1, label); } void gdk_gl_context_label_object_printf (GdkGLContext *context, guint identifier, guint name, const char *format, ...) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); char *message; va_list args; if (priv->use_khr_debug) { int msg_len; va_start (args, format); message = g_strdup_vprintf (format, args); va_end (args); msg_len = MIN (priv->max_debug_label_length, strlen (message) - 1); glObjectLabel (identifier, name, msg_len, message); g_free (message); } } gboolean gdk_gl_context_has_unpack_subimage (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); return priv->has_unpack_subimage; } static gboolean gdk_gl_context_is_realized (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); return priv->api != 0; } /** * gdk_gl_context_set_debug_enabled: * @context: a `GdkGLContext` * @enabled: whether to enable debugging in the context * * Sets whether the `GdkGLContext` should perform extra validations and * runtime checking. * * This is useful during development, but has additional overhead. * * The `GdkGLContext` must not be realized or made current prior to * calling this function. */ void gdk_gl_context_set_debug_enabled (GdkGLContext *context, gboolean enabled) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_if_fail (GDK_IS_GL_CONTEXT (context)); g_return_if_fail (!gdk_gl_context_is_realized (context)); enabled = !!enabled; priv->debug_enabled = enabled; } /** * gdk_gl_context_get_debug_enabled: * @context: a `GdkGLContext` * * Retrieves whether the context is doing extra validations and runtime checking. * * See [method@Gdk.GLContext.set_debug_enabled]. * * Returns: %TRUE if debugging is enabled */ gboolean gdk_gl_context_get_debug_enabled (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), FALSE); return priv->debug_enabled; } /** * gdk_gl_context_set_forward_compatible: * @context: a `GdkGLContext` * @compatible: whether the context should be forward-compatible * * Sets whether the `GdkGLContext` should be forward-compatible. * * Forward-compatible contexts must not support OpenGL functionality that * has been marked as deprecated in the requested version; non-forward * compatible contexts, on the other hand, must support both deprecated and * non deprecated functionality. * * The `GdkGLContext` must not be realized or made current prior to calling * this function. */ void gdk_gl_context_set_forward_compatible (GdkGLContext *context, gboolean compatible) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_if_fail (GDK_IS_GL_CONTEXT (context)); g_return_if_fail (!gdk_gl_context_is_realized (context)); compatible = !!compatible; priv->forward_compatible = compatible; } /** * gdk_gl_context_get_forward_compatible: * @context: a `GdkGLContext` * * Retrieves whether the context is forward-compatible. * * See [method@Gdk.GLContext.set_forward_compatible]. * * Returns: %TRUE if the context should be forward-compatible */ gboolean gdk_gl_context_get_forward_compatible (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), FALSE); return priv->forward_compatible; } /** * gdk_gl_context_set_required_version: * @context: a `GdkGLContext` * @major: the major version to request * @minor: the minor version to request * * Sets the major and minor version of OpenGL to request. * * Setting @major and @minor to zero will use the default values. * * The `GdkGLContext` must not be realized or made current prior to calling * this function. */ void gdk_gl_context_set_required_version (GdkGLContext *context, int major, int minor) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); gboolean force_gles = FALSE; int version, min_ver; #ifdef G_ENABLE_DEBUG GdkDisplay *display; #endif g_return_if_fail (GDK_IS_GL_CONTEXT (context)); g_return_if_fail (!gdk_gl_context_is_realized (context)); /* this will take care of the default */ if (major == 0 && minor == 0) { priv->major = 0; priv->minor = 0; return; } version = (major * 100) + minor; #ifdef G_ENABLE_DEBUG display = gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)); force_gles = GDK_DISPLAY_DEBUG_CHECK (display, GL_GLES); #endif /* Enforce a minimum context version number of 3.2 for desktop GL, * and 2.0 for GLES */ if (gdk_gl_context_get_use_es (context) || force_gles) min_ver = 200; else min_ver = 302; if (version < min_ver) { g_warning ("gdk_gl_context_set_required_version - GL context versions less than 3.2 are not supported."); version = min_ver; } priv->major = version / 100; priv->minor = version % 100; } gboolean gdk_gl_context_check_version (GdkGLContext *context, int required_major, int required_minor) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), FALSE); g_return_val_if_fail (required_minor < 10, FALSE); return priv->gl_version >= required_major * 10 + required_minor; } /** * gdk_gl_context_get_required_version: * @context: a `GdkGLContext` * @major: (out) (nullable): return location for the major version to request * @minor: (out) (nullable): return location for the minor version to request * * Retrieves required OpenGL version. * * See [method@Gdk.GLContext.set_required_version]. */ void gdk_gl_context_get_required_version (GdkGLContext *context, int *major, int *minor) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); gboolean force_gles = FALSE; #ifdef G_ENABLE_DEBUG GdkDisplay *display; #endif int default_major, default_minor; int maj, min; g_return_if_fail (GDK_IS_GL_CONTEXT (context)); #ifdef G_ENABLE_DEBUG display = gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)); force_gles = GDK_DISPLAY_DEBUG_CHECK (display, GL_GLES); #endif /* Default fallback values for uninitialised contexts; we * enforce a context version number of 3.2 for desktop GL, * and 2.0 for GLES */ if (gdk_gl_context_get_use_es (context) || force_gles) { default_major = 2; default_minor = 0; } else { default_major = 3; default_minor = 2; } if (priv->major > 0) maj = priv->major; else maj = default_major; if (priv->minor > 0) min = priv->minor; else min = default_minor; if (major != NULL) *major = maj; if (minor != NULL) *minor = min; } /** * gdk_gl_context_is_legacy: * @context: a `GdkGLContext` * * Whether the `GdkGLContext` is in legacy mode or not. * * The `GdkGLContext` must be realized before calling this function. * * When realizing a GL context, GDK will try to use the OpenGL 3.2 core * profile; this profile removes all the OpenGL API that was deprecated * prior to the 3.2 version of the specification. If the realization is * successful, this function will return %FALSE. * * If the underlying OpenGL implementation does not support core profiles, * GDK will fall back to a pre-3.2 compatibility profile, and this function * will return %TRUE. * * You can use the value returned by this function to decide which kind * of OpenGL API to use, or whether to do extension discovery, or what * kind of shader programs to load. * * Returns: %TRUE if the GL context is in legacy mode */ gboolean gdk_gl_context_is_legacy (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), FALSE); g_return_val_if_fail (gdk_gl_context_is_realized (context), FALSE); return priv->is_legacy; } void gdk_gl_context_set_is_legacy (GdkGLContext *context, gboolean is_legacy) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); priv->is_legacy = !!is_legacy; } /** * gdk_gl_context_is_shared: * @self: a `GdkGLContext` * @other: the `GdkGLContext` that should be compatible with @self * * Checks if the two GL contexts can share resources. * * When they can, the texture IDs from @other can be used in @self. This * is particularly useful when passing `GdkGLTexture` objects between * different contexts. * * Contexts created for the same display with the same properties will * always be compatible, even if they are created for different surfaces. * For other contexts it depends on the GL backend. * * Both contexts must be realized for this check to succeed. If either one * is not, this function will return %FALSE. * * Returns: %TRUE if the two GL contexts are compatible. * * Since: 4.4 */ gboolean gdk_gl_context_is_shared (GdkGLContext *self, GdkGLContext *other) { g_return_val_if_fail (GDK_IS_GL_CONTEXT (self), FALSE); g_return_val_if_fail (GDK_IS_GL_CONTEXT (other), FALSE); if (!gdk_gl_context_is_realized (self) || !gdk_gl_context_is_realized (other)) return FALSE; return GDK_GL_CONTEXT_GET_CLASS (self)->is_shared (self, other); } /** * gdk_gl_context_set_allowed_apis: (attributes org.gtk.Method.set_property=allowed-apis) * @self: a GL context * @apis: the allowed APIs * * Sets the allowed APIs. When gdk_gl_context_realize() is called, only the * allowed APIs will be tried. If you set this to 0, realizing will always fail. * * If you set it on a realized context, the property will not have any effect. * It is only relevant during gdk_gl_context_realize(). * * By default, all APIs are allowed. * * Since: 4.6 **/ void gdk_gl_context_set_allowed_apis (GdkGLContext *self, GdkGLAPI apis) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); g_return_if_fail (GDK_IS_GL_CONTEXT (self)); if (priv->allowed_apis == apis) return; priv->allowed_apis = apis; g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ALLOWED_APIS]); } /** * gdk_gl_context_get_allowed_apis: (attributes org.gtk.Method.get_property=allowed-apis) * @self: a GL context * * Gets the allowed APIs set via gdk_gl_context_set_allowed_apis(). * * Returns: the allowed APIs * * Since: 4.6 **/ GdkGLAPI gdk_gl_context_get_allowed_apis (GdkGLContext *self) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); g_return_val_if_fail (GDK_IS_GL_CONTEXT (self), 0); return priv->allowed_apis; } /** * gdk_gl_context_get_api: (attributes org.gtk.Method.get_property=api) * @self: a GL context * * Gets the API currently in use. * * If the renderer has not been realized yet, 0 is returned. * * Returns: the currently used API * * Since: 4.6 **/ GdkGLAPI gdk_gl_context_get_api (GdkGLContext *self) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); g_return_val_if_fail (GDK_IS_GL_CONTEXT (self), 0); return priv->api; } gboolean gdk_gl_context_is_api_allowed (GdkGLContext *self, GdkGLAPI api, GError **error) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); if (GDK_DISPLAY_DEBUG_CHECK (gdk_gl_context_get_display (self), GL_GLES)) { if (!(api & GDK_GL_API_GLES)) { g_set_error_literal (error, GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE, _("Anything but OpenGL ES disabled via GDK_DEBUG")); return FALSE; } } if (priv->allowed_apis & api) return TRUE; g_set_error (error, GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE, _("Application does not support %s API"), api == GDK_GL_API_GL ? "OpenGL" : "OpenGL ES"); return FALSE; } /** * gdk_gl_context_set_use_es: * @context: a `GdkGLContext` * @use_es: whether the context should use OpenGL ES instead of OpenGL, * or -1 to allow auto-detection * * Requests that GDK create an OpenGL ES context instead of an OpenGL one. * * Not all platforms support OpenGL ES. * * The @context must not have been realized. * * By default, GDK will attempt to automatically detect whether the * underlying GL implementation is OpenGL or OpenGL ES once the @context * is realized. * * You should check the return value of [method@Gdk.GLContext.get_use_es] * after calling [method@Gdk.GLContext.realize] to decide whether to use * the OpenGL or OpenGL ES API, extensions, or shaders. */ void gdk_gl_context_set_use_es (GdkGLContext *context, int use_es) { g_return_if_fail (GDK_IS_GL_CONTEXT (context)); g_return_if_fail (!gdk_gl_context_is_realized (context)); switch (use_es) { case -1: gdk_gl_context_set_allowed_apis (context, DEFAULT_ALLOWED_APIS); break; case 0: gdk_gl_context_set_allowed_apis (context, GDK_GL_API_GL); break; case 1: gdk_gl_context_set_allowed_apis (context, GDK_GL_API_GLES); break; default: /* Just ignore the call */ break; } } /** * gdk_gl_context_get_use_es: * @context: a `GdkGLContext` * * Checks whether the @context is using an OpenGL or OpenGL ES profile. * * Returns: %TRUE if the `GdkGLContext` is using an OpenGL ES profile */ gboolean gdk_gl_context_get_use_es (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), FALSE); return priv->api == GDK_GL_API_GLES; } static void APIENTRY gl_debug_message_callback (GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void *user_data) { const char *message_source; const char *message_type; const char *message_severity; if (severity == GL_DEBUG_SEVERITY_NOTIFICATION) return; switch (source) { case GL_DEBUG_SOURCE_API: message_source = "API"; break; case GL_DEBUG_SOURCE_WINDOW_SYSTEM: message_source = "Window System"; break; case GL_DEBUG_SOURCE_SHADER_COMPILER: message_source = "Shader Compiler"; break; case GL_DEBUG_SOURCE_THIRD_PARTY: message_source = "Third Party"; break; case GL_DEBUG_SOURCE_APPLICATION: message_source = "Application"; break; case GL_DEBUG_SOURCE_OTHER: default: message_source = "Other"; } switch (type) { case GL_DEBUG_TYPE_ERROR: message_type = "Error"; break; case GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR: message_type = "Deprecated Behavior"; break; case GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR: message_type = "Undefined Behavior"; break; case GL_DEBUG_TYPE_PORTABILITY: message_type = "Portability"; break; case GL_DEBUG_TYPE_PERFORMANCE: message_type = "Performance"; break; case GL_DEBUG_TYPE_MARKER: message_type = "Marker"; break; case GL_DEBUG_TYPE_PUSH_GROUP: message_type = "Push Group"; break; case GL_DEBUG_TYPE_POP_GROUP: message_type = "Pop Group"; break; case GL_DEBUG_TYPE_OTHER: default: message_type = "Other"; } switch (severity) { case GL_DEBUG_SEVERITY_HIGH: message_severity = "High"; break; case GL_DEBUG_SEVERITY_MEDIUM: message_severity = "Medium"; break; case GL_DEBUG_SEVERITY_LOW: message_severity = "Low"; break; case GL_DEBUG_SEVERITY_NOTIFICATION: message_severity = "Notification"; break; default: message_severity = "Unknown"; } g_warning ("OPENGL:\n Source: %s\n Type: %s\n Severity: %s\n Message: %s", message_source, message_type, message_severity, message); } /** * gdk_gl_context_realize: * @context: a `GdkGLContext` * @error: return location for a `GError` * * Realizes the given `GdkGLContext`. * * It is safe to call this function on a realized `GdkGLContext`. * * Returns: %TRUE if the context is realized */ gboolean gdk_gl_context_realize (GdkGLContext *context, GError **error) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), FALSE); if (priv->api) return TRUE; priv->api = GDK_GL_CONTEXT_GET_CLASS (context)->realize (context, error); if (priv->api) g_object_notify_by_pspec (G_OBJECT (context), properties[PROP_API]); return priv->api; } static void gdk_gl_context_check_extensions (GdkGLContext *context) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); gboolean gl_debug = FALSE; #ifdef G_ENABLE_DEBUG GdkDisplay *display; #endif if (!gdk_gl_context_is_realized (context)) return; if (priv->extensions_checked) return; priv->gl_version = epoxy_gl_version (); priv->has_debug_output = epoxy_has_gl_extension ("GL_ARB_debug_output") || epoxy_has_gl_extension ("GL_KHR_debug"); #ifdef G_ENABLE_DEBUG display = gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)); gl_debug = GDK_DISPLAY_DEBUG_CHECK (display, GL_DEBUG); #endif if (priv->has_debug_output #ifndef G_ENABLE_CONSISTENCY_CHECKS && gl_debug #endif ) { gdk_gl_context_make_current (context); glEnable (GL_DEBUG_OUTPUT); glEnable (GL_DEBUG_OUTPUT_SYNCHRONOUS); glDebugMessageCallback (gl_debug_message_callback, NULL); } if (gdk_gl_context_get_use_es (context)) { priv->has_unpack_subimage = epoxy_has_gl_extension ("GL_EXT_unpack_subimage"); priv->has_khr_debug = epoxy_has_gl_extension ("GL_KHR_debug"); } else { priv->has_unpack_subimage = TRUE; priv->has_khr_debug = epoxy_has_gl_extension ("GL_KHR_debug"); /* We asked for a core profile, but we didn't get one, so we're in legacy mode */ if (priv->gl_version < 32) priv->is_legacy = TRUE; } if (priv->has_khr_debug && gl_debug) { priv->use_khr_debug = TRUE; glGetIntegerv (GL_MAX_LABEL_LENGTH, &priv->max_debug_label_length); } GDK_DISPLAY_NOTE (gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)), OPENGL, g_message ("%s version: %d.%d (%s)\n" "* GLSL version: %s\n" "* Extensions checked:\n" " - GL_KHR_debug: %s\n" " - GL_EXT_unpack_subimage: %s", gdk_gl_context_get_use_es (context) ? "OpenGL ES" : "OpenGL", priv->gl_version / 10, priv->gl_version % 10, priv->is_legacy ? "legacy" : "core", glGetString (GL_SHADING_LANGUAGE_VERSION), priv->has_khr_debug ? "yes" : "no", priv->has_unpack_subimage ? "yes" : "no")); priv->extensions_checked = TRUE; } /** * gdk_gl_context_make_current: * @context: a `GdkGLContext` * * Makes the @context the current one. */ void gdk_gl_context_make_current (GdkGLContext *context) { MaskedContext *current, *masked_context; gboolean surfaceless; g_return_if_fail (GDK_IS_GL_CONTEXT (context)); surfaceless = !gdk_draw_context_is_in_frame (GDK_DRAW_CONTEXT (context)); masked_context = mask_context (context, surfaceless); current = g_private_get (&thread_current_context); if (current == masked_context) return; /* we need to realize the GdkGLContext if it wasn't explicitly realized */ if (!gdk_gl_context_is_realized (context)) { GError *error = NULL; gdk_gl_context_realize (context, &error); if (error != NULL) { g_critical ("Could not realize the GL context: %s", error->message); g_error_free (error); return; } } if (!GDK_GL_CONTEXT_GET_CLASS (context)->make_current (context, surfaceless)) { g_warning ("gdk_gl_context_make_current() failed"); return; } g_object_ref (context); g_private_replace (&thread_current_context, masked_context); gdk_gl_context_check_extensions (context); } /** * gdk_gl_context_get_display: * @context: a `GdkGLContext` * * Retrieves the display the @context is created for * * Returns: (nullable) (transfer none): a `GdkDisplay` */ GdkDisplay * gdk_gl_context_get_display (GdkGLContext *context) { g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), NULL); return gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)); } /** * gdk_gl_context_get_surface: * @context: a `GdkGLContext` * * Retrieves the surface used by the @context. * * Returns: (nullable) (transfer none): a `GdkSurface` */ GdkSurface * gdk_gl_context_get_surface (GdkGLContext *context) { g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), NULL); return gdk_draw_context_get_surface (GDK_DRAW_CONTEXT (context)); } /** * gdk_gl_context_get_shared_context: (attributes org.gtk.Method.get_property=shared-context) * @context: a `GdkGLContext` * * Used to retrieves the `GdkGLContext` that this @context share data with. * * As many contexts can share data now and no single shared context exists * anymore, this function has been deprecated and now always returns %NULL. * * Returns: (nullable) (transfer none): %NULL * * Deprecated: 4.4: Use [method@Gdk.GLContext.is_shared] to check if contexts * can be shared. */ GdkGLContext * gdk_gl_context_get_shared_context (GdkGLContext *context) { g_return_val_if_fail (GDK_IS_GL_CONTEXT (context), NULL); return NULL; } /** * gdk_gl_context_get_version: * @context: a `GdkGLContext` * @major: (out): return location for the major version * @minor: (out): return location for the minor version * * Retrieves the OpenGL version of the @context. * * The @context must be realized prior to calling this function. */ void gdk_gl_context_get_version (GdkGLContext *context, int *major, int *minor) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context); g_return_if_fail (GDK_IS_GL_CONTEXT (context)); g_return_if_fail (gdk_gl_context_is_realized (context)); if (major != NULL) *major = priv->gl_version / 10; if (minor != NULL) *minor = priv->gl_version % 10; } /** * gdk_gl_context_clear_current: * * Clears the current `GdkGLContext`. * * Any OpenGL call after this function returns will be ignored * until [method@Gdk.GLContext.make_current] is called. */ void gdk_gl_context_clear_current (void) { MaskedContext *current; current = g_private_get (&thread_current_context); if (current != NULL) { GdkGLContext *context = unmask_context (current); if (GDK_GL_CONTEXT_GET_CLASS (context)->clear_current (context)) g_private_replace (&thread_current_context, NULL); } } /** * gdk_gl_context_get_current: * * Retrieves the current `GdkGLContext`. * * Returns: (nullable) (transfer none): the current `GdkGLContext` */ GdkGLContext * gdk_gl_context_get_current (void) { MaskedContext *current; current = g_private_get (&thread_current_context); return unmask_context (current); } gboolean gdk_gl_context_has_debug (GdkGLContext *self) { GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (self); return priv->debug_enabled || priv->use_khr_debug; } /* This is currently private! */ /* When using GL/ES, don't flip the 'R' and 'B' bits on Windows/ANGLE for glReadPixels() */ gboolean gdk_gl_context_use_es_bgra (GdkGLContext *context) { if (!gdk_gl_context_get_use_es (context)) return FALSE; #ifdef GDK_WINDOWING_WIN32 if (GDK_WIN32_IS_GL_CONTEXT (context)) return TRUE; #endif return FALSE; } static GdkGLBackend the_gl_backend_type = GDK_GL_NONE; static const char *gl_backend_names[] = { [GDK_GL_NONE] = "No GL (You should never read this)", [GDK_GL_EGL] = "EGL", [GDK_GL_GLX] = "X11 GLX", [GDK_GL_WGL] = "Windows WGL", [GDK_GL_CGL] = "Apple CGL" }; /* * gdk_gl_backend_can_be_used: * @backend_type: Type of backend to check * @error: Return location for an error * * Checks if this backend type can be used. When multiple displays * are opened that use different GL backends, conflicts can arise, * so this function checks that all displays use compatible GL * backends. * * Returns: %TRUE if the backend can still be used */ gboolean gdk_gl_backend_can_be_used (GdkGLBackend backend_type, GError **error) { if (the_gl_backend_type == GDK_GL_NONE || the_gl_backend_type == backend_type) return TRUE; g_set_error (error, GDK_GL_ERROR, GDK_GL_ERROR_NOT_AVAILABLE, /* translators: This is about OpenGL backend names, like * "Trying to use X11 GLX, but EGL is already in use" */ _("Trying to use %s, but %s is already in use"), gl_backend_names[backend_type], gl_backend_names[the_gl_backend_type]); return FALSE; } /* * gdk_gl_backend_use: * @backend_type: Type of backend * * Ensures that the backend in use is the given one. If another backend * is already in use, this function will abort the program. It should * have previously checked via gdk_gl_backend_can_be_used(). **/ void gdk_gl_backend_use (GdkGLBackend backend_type) { /* Check that the context class is properly initializing its backend type */ g_assert (backend_type != GDK_GL_NONE); if (the_gl_backend_type == GDK_GL_NONE) { the_gl_backend_type = backend_type; /* This is important!!!11eleven * (But really: How do I print a message in 2 categories?) */ GDK_NOTE (OPENGL, g_print ("Using OpenGL backend %s\n", gl_backend_names[the_gl_backend_type])); GDK_NOTE (MISC, g_message ("Using Opengl backend %s", gl_backend_names[the_gl_backend_type])); } g_assert (the_gl_backend_type == backend_type); }