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

This allows virtio-gpu to render in 3d mode.
Uses native opengl support which is present
in gtk versions 3.16 and newer.

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

1 files changed, 223 insertions, 0 deletions

diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
new file mode 100644
index 0000000..dec3edb
--- /dev/null
+++ b/ui/gtk-gl-area.c
@@ -0,0 +1,223 @@
+/*
+ * GTK UI -- glarea opengl code.
+ *
+ * Requires 3.16+ (GtkGLArea widget).
+ *
+ * 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"
+
+static void gtk_gl_area_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_gl_area_draw(VirtualConsole *vc)
+{
+    int ww, wh, y1, y2;
+
+    if (!vc->gfx.gls) {
+        return;
+    }
+
+    gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+    ww = gtk_widget_get_allocated_width(vc->gfx.drawing_area);
+    wh = gtk_widget_get_allocated_height(vc->gfx.drawing_area);
+
+    if (vc->gfx.scanout_mode) {
+        if (!vc->gfx.fbo_id) {
+            return;
+        }
+
+        glBindFramebuffer(GL_READ_FRAMEBUFFER, vc->gfx.fbo_id);
+        /* GtkGLArea sets GL_DRAW_FRAMEBUFFER for us */
+
+        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);
+    } else {
+        if (!vc->gfx.ds) {
+            return;
+        }
+        gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+
+        surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, ww, wh);
+        surface_gl_render_texture(vc->gfx.gls, vc->gfx.ds);
+    }
+}
+
+void gd_gl_area_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;
+    }
+
+    gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+    surface_gl_update_texture(vc->gfx.gls, vc->gfx.ds, x, y, w, h);
+    vc->gfx.glupdates++;
+}
+
+void gd_gl_area_refresh(DisplayChangeListener *dcl)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    if (!vc->gfx.gls) {
+        if (!gtk_widget_get_realized(vc->gfx.drawing_area)) {
+            return;
+        }
+        gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+        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;
+        gtk_gl_area_set_scanout_mode(vc, false);
+        gtk_gl_area_queue_render(GTK_GL_AREA(vc->gfx.drawing_area));
+    }
+}
+
+void gd_gl_area_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;
+    }
+
+    if (vc->gfx.gls) {
+        gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+        surface_gl_destroy_texture(vc->gfx.gls, vc->gfx.ds);
+        surface_gl_create_texture(vc->gfx.gls, surface);
+    }
+    vc->gfx.ds = surface;
+
+    if (resized) {
+        gd_update_windowsize(vc);
+    }
+}
+
+QEMUGLContext gd_gl_area_create_context(DisplayChangeListener *dcl,
+                                        QEMUGLParams *params)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+    GdkWindow *window;
+    GdkGLContext *ctx;
+    GError *err = NULL;
+
+    gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+    window = gtk_widget_get_window(vc->gfx.drawing_area);
+    ctx = gdk_window_create_gl_context(window, &err);
+    gdk_gl_context_set_required_version(ctx,
+                                        params->major_ver,
+                                        params->minor_ver);
+    gdk_gl_context_realize(ctx, &err);
+    return ctx;
+}
+
+void gd_gl_area_destroy_context(DisplayChangeListener *dcl, QEMUGLContext ctx)
+{
+    /* FIXME */
+}
+
+void gd_gl_area_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;
+
+    gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
+
+    if (vc->gfx.tex_id == 0 || vc->gfx.w == 0 || vc->gfx.h == 0) {
+        gtk_gl_area_set_scanout_mode(vc, false);
+        return;
+    }
+
+    gtk_gl_area_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_gl_area_scanout_flush(DisplayChangeListener *dcl,
+                          uint32_t x, uint32_t y, uint32_t w, uint32_t h)
+{
+    VirtualConsole *vc = container_of(dcl, VirtualConsole, gfx.dcl);
+
+    gtk_gl_area_queue_render(GTK_GL_AREA(vc->gfx.drawing_area));
+}
+
+void gtk_gl_area_init(void)
+{
+    display_opengl = 1;
+}
+
+QEMUGLContext gd_gl_area_get_current_context(DisplayChangeListener *dcl)
+{
+    return gdk_gl_context_get_current();
+}
+
+int gd_gl_area_make_current(DisplayChangeListener *dcl,
+                            QEMUGLContext ctx)
+{
+    gdk_gl_context_make_current(ctx);
+    return 0;
+}