gtk: add opengl support, using egl

This adds opengl rendering support to the gtk ui, using egl.
It's off by default for now, use 'qemu -display gtk,gl=on'
to play with this.

Note that gtk got native opengl support with release 3.16.
There most likely will be a separate implementation for 3.16+,
using the native gtk opengl support.  This patch covers older
versions (and for the time being 3.16 too, hopefully without
rendering quirks).

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 141 insertions, 0 deletions

diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
new file mode 100644
index 0000000000..15b41f2bab
--- /dev/null
+++ b/ui/gtk-egl.c
@@ -0,0 +1,141 @@
+/*
+ * GTK UI -- egl opengl code.
+ *
+ * Note that gtk 3.16+ (released 2015-03-23) has a GtkGLArea widget,
+ * which is GtkDrawingArea like widget with opengl rendering support.
+ *
+ * This code handles opengl support on older gtk versions, using egl
+ * to get a opengl context for the X11 window.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu-common.h"
+
+#include "trace.h"
+
+#include "ui/console.h"
+#include "ui/gtk.h"
+#include "ui/egl-helpers.h"
+
+#include "sysemu/sysemu.h"
+
+/** DisplayState Callbacks (opengl version) **/
+
+void gd_egl_init(VirtualConsole *vc)
+{
+    GdkWindow *gdk_window = gtk_widget_get_window(vc->gfx.drawing_area);
+    if (!gdk_window) {
+        return;
+    }
+
+#if GTK_CHECK_VERSION(3, 0, 0)
+    Window x11_window = gdk_x11_window_get_xid(gdk_window);
+#else
+    Window x11_window = gdk_x11_drawable_get_xid(gdk_window);
+#endif
+    if (!x11_window) {
+        return;
+    }
+
+    vc->gfx.ectx = qemu_egl_init_ctx();
+    vc->gfx.esurface = qemu_egl_init_surface_x11(vc->gfx.ectx, x11_window);
+
+    assert(vc->gfx.esurface);
+}
+
+void gd_egl_draw(VirtualConsole *vc)
+{
+    GdkWindow *window;
+    int ww, wh;
+
+    if (!vc->gfx.gls || !vc->gfx.ds) {
+        return;
+    }
+
+    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                   vc->gfx.esurface, vc->gfx.ectx);
+
+    window = gtk_widget_get_window(vc->gfx.drawing_area);
+    gdk_drawable_get_size(window, &ww, &wh);
+    surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, ww, wh);
+    surface_gl_render_texture(vc->gfx.gls, vc->gfx.ds);
+
+    eglSwapBuffers(qemu_egl_display, vc->gfx.esurface);
+}
+
+void gd_egl_update(DisplayChangeListener *dcl,
+                   int x, int y, int w, int h)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    if (!vc->gfx.gls || !vc->gfx.ds) {
+        return;
+    }
+
+    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                   vc->gfx.esurface, vc->gfx.ectx);
+    surface_gl_update_texture(vc->gfx.gls, vc->gfx.ds, x, y, w, h);
+    vc->gfx.glupdates++;
+}
+
+void gd_egl_refresh(DisplayChangeListener *dcl)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    if (!vc->gfx.esurface) {
+        gd_egl_init(vc);
+        if (!vc->gfx.esurface) {
+            return;
+        }
+        vc->gfx.gls = console_gl_init_context();
+        if (vc->gfx.ds) {
+            surface_gl_create_texture(vc->gfx.gls, vc->gfx.ds);
+        }
+    }
+
+    graphic_hw_update(dcl->con);
+
+    if (vc->gfx.glupdates) {
+        vc->gfx.glupdates = 0;
+        gd_egl_draw(vc);
+    }
+}
+
+void gd_egl_switch(DisplayChangeListener *dcl,
+                   DisplaySurface *surface)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+    bool resized = true;
+
+    trace_gd_switch(vc->label, surface_width(surface), surface_height(surface));
+
+    if (vc->gfx.ds &&
+        surface_width(vc->gfx.ds) == surface_width(surface) &&
+        surface_height(vc->gfx.ds) == surface_height(surface)) {
+        resized = false;
+    }
+
+    surface_gl_destroy_texture(vc->gfx.gls, vc->gfx.ds);
+    vc->gfx.ds = surface;
+    if (vc->gfx.gls) {
+        surface_gl_create_texture(vc->gfx.gls, vc->gfx.ds);
+    }
+
+    if (resized) {
+        gd_update_windowsize(vc);
+    }
+}
+
+void gtk_egl_init(void)
+{
+    GdkDisplay *gdk_display = gdk_display_get_default();
+    Display *x11_display = gdk_x11_display_get_xdisplay(gdk_display);
+
+    if (qemu_egl_init_dpy(x11_display, false, false) < 0) {
+        return;
+    }
+
+    display_opengl = 1;
+}