gtk/opengl: add opengl context and scanout support (egl)

This allows virtio-gpu to render in 3d mode.
Uses egl, for gtk versions 3.14 and older.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

3 files changed, 146 insertions, 8 deletions

diff --git a/include/ui/gtk.h b/include/ui/gtk.h
index 0359333fce..b490e82e70 100644
--- a/include/ui/gtk.h
+++ b/include/ui/gtk.h
@@ -20,6 +20,7 @@
 
 #if defined(CONFIG_OPENGL)
 #include "ui/egl-helpers.h"
+#include "ui/egl-context.h"
 #endif
 
 /* Compatibility define to let us build on both Gtk2 and Gtk3 */
@@ -46,6 +47,11 @@ typedef struct VirtualGfxConsole {
     EGLContext ectx;
     EGLSurface esurface;
     int glupdates;
+    int x, y, w, h;
+    GLuint tex_id;
+    GLuint fbo_id;
+    bool y0_top;
+    bool scanout_mode;
 #endif
 } VirtualGfxConsole;
 
@@ -90,6 +96,16 @@ void gd_egl_update(DisplayChangeListener *dcl,
 void gd_egl_refresh(DisplayChangeListener *dcl);
 void gd_egl_switch(DisplayChangeListener *dcl,
                    DisplaySurface *surface);
+QEMUGLContext gd_egl_create_context(DisplayChangeListener *dcl,
+                                    QEMUGLParams *params);
+void gd_egl_scanout(DisplayChangeListener *dcl,
+                    uint32_t backing_id, bool backing_y_0_top,
+                    uint32_t x, uint32_t y,
+                    uint32_t w, uint32_t h);
+void gd_egl_scanout_flush(DisplayChangeListener *dcl,
+                          uint32_t x, uint32_t y, uint32_t w, uint32_t h);
 void gtk_egl_init(void);
+int gd_egl_make_current(DisplayChangeListener *dcl,
+                        QEMUGLContext ctx);
 
 #endif /* UI_GTK_H */
diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index 15b41f2bab..500c42c9fa 100644
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -21,6 +21,29 @@
 
 #include "sysemu/sysemu.h"
 
+static void gtk_egl_set_scanout_mode(VirtualConsole *vc, bool scanout)
+{
+    if (vc->gfx.scanout_mode == scanout) {
+        return;
+    }
+
+    vc->gfx.scanout_mode = scanout;
+    if (!vc->gfx.scanout_mode) {
+        if (vc->gfx.fbo_id) {
+            glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
+                                      GL_COLOR_ATTACHMENT0_EXT,
+                                      GL_TEXTURE_2D, 0, 0);
+            glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
+            glDeleteFramebuffers(1, &vc->gfx.fbo_id);
+            vc->gfx.fbo_id = 0;
+        }
+        if (vc->gfx.surface) {
+            surface_gl_destroy_texture(vc->gfx.gls, vc->gfx.ds);
+            surface_gl_create_texture(vc->gfx.gls, vc->gfx.ds);
+        }
+    }
+}
+
 /** DisplayState Callbacks (opengl version) **/
 
 void gd_egl_init(VirtualConsole *vc)
@@ -50,19 +73,26 @@ void gd_egl_draw(VirtualConsole *vc)
     GdkWindow *window;
     int ww, wh;
 
-    if (!vc->gfx.gls || !vc->gfx.ds) {
+    if (!vc->gfx.gls) {
         return;
     }
 
-    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
-                   vc->gfx.esurface, vc->gfx.ectx);
+    if (vc->gfx.scanout_mode) {
+        gd_egl_scanout_flush(&vc->gfx.dcl, 0, 0, vc->gfx.w, vc->gfx.h);
+    } else {
+        if (!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);
+        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);
+        eglSwapBuffers(qemu_egl_display, vc->gfx.esurface);
+    }
 }
 
 void gd_egl_update(DisplayChangeListener *dcl,
@@ -99,6 +129,7 @@ void gd_egl_refresh(DisplayChangeListener *dcl)
 
     if (vc->gfx.glupdates) {
         vc->gfx.glupdates = 0;
+        gtk_egl_set_scanout_mode(vc, false);
         gd_egl_draw(vc);
     }
 }
@@ -128,6 +159,81 @@ void gd_egl_switch(DisplayChangeListener *dcl,
     }
 }
 
+QEMUGLContext gd_egl_create_context(DisplayChangeListener *dcl,
+                                    QEMUGLParams *params)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                   vc->gfx.esurface, vc->gfx.ectx);
+    return qemu_egl_create_context(dcl, params);
+}
+
+void gd_egl_scanout(DisplayChangeListener *dcl,
+                    uint32_t backing_id, bool backing_y_0_top,
+                    uint32_t x, uint32_t y,
+                    uint32_t w, uint32_t h)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    vc->gfx.x = x;
+    vc->gfx.y = y;
+    vc->gfx.w = w;
+    vc->gfx.h = h;
+    vc->gfx.tex_id = backing_id;
+    vc->gfx.y0_top = backing_y_0_top;
+
+    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                   vc->gfx.esurface, vc->gfx.ectx);
+
+    if (vc->gfx.tex_id == 0 || vc->gfx.w == 0 || vc->gfx.h == 0) {
+        gtk_egl_set_scanout_mode(vc, false);
+        return;
+    }
+
+    gtk_egl_set_scanout_mode(vc, true);
+    if (!vc->gfx.fbo_id) {
+        glGenFramebuffers(1, &vc->gfx.fbo_id);
+    }
+
+    glBindFramebuffer(GL_FRAMEBUFFER_EXT, vc->gfx.fbo_id);
+    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+                              GL_TEXTURE_2D, vc->gfx.tex_id, 0);
+}
+
+void gd_egl_scanout_flush(DisplayChangeListener *dcl,
+                          uint32_t x, uint32_t y, uint32_t w, uint32_t h)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+    GdkWindow *window;
+    int ww, wh, y1, y2;
+
+    if (!vc->gfx.scanout_mode) {
+        return;
+    }
+    if (!vc->gfx.fbo_id) {
+        return;
+    }
+
+    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                   vc->gfx.esurface, vc->gfx.ectx);
+
+    glBindFramebuffer(GL_READ_FRAMEBUFFER, vc->gfx.fbo_id);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+
+    window = gtk_widget_get_window(vc->gfx.drawing_area);
+    gdk_drawable_get_size(window, &ww, &wh);
+    glViewport(0, 0, ww, wh);
+    y1 = vc->gfx.y0_top ? 0 : vc->gfx.h;
+    y2 = vc->gfx.y0_top ? vc->gfx.h : 0;
+    glBlitFramebuffer(0, y1, vc->gfx.w, y2,
+                      0, 0, ww, wh,
+                      GL_COLOR_BUFFER_BIT, GL_NEAREST);
+    glBindFramebuffer(GL_FRAMEBUFFER_EXT, vc->gfx.fbo_id);
+
+    eglSwapBuffers(qemu_egl_display, vc->gfx.esurface);
+}
+
 void gtk_egl_init(void)
 {
     GdkDisplay *gdk_display = gdk_display_get_default();
@@ -139,3 +245,12 @@ void gtk_egl_init(void)
 
     display_opengl = 1;
 }
+
+int gd_egl_make_current(DisplayChangeListener *dcl,
+                        QEMUGLContext ctx)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    return eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                          vc->gfx.esurface, ctx);
+}
diff --git a/ui/gtk.c b/ui/gtk.c
index 3057cdc3f7..e6e35323b1 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -615,6 +615,13 @@ static const DisplayChangeListenerOps dcl_egl_ops = {
     .dpy_refresh          = gd_egl_refresh,
     .dpy_mouse_set        = gd_mouse_set,
     .dpy_cursor_define    = gd_cursor_define,
+
+    .dpy_gl_ctx_create       = gd_egl_create_context,
+    .dpy_gl_ctx_destroy      = qemu_egl_destroy_context,
+    .dpy_gl_ctx_make_current = gd_egl_make_current,
+    .dpy_gl_ctx_get_current  = qemu_egl_get_current_context,
+    .dpy_gl_scanout          = gd_egl_scanout,
+    .dpy_gl_update           = gd_egl_scanout_flush,
 };
 
 #endif