[gtk/master.win32] GdkGLContext: Drop gdk_gl_context_has_[framebuffer_blit|frame_terminator]()

[Chun-wei Fan <fanchunwei src gnome org>]

commit edc1c2823616c0cb21e64820fb009b2c028b811d
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Aug 5 18:56:57 2020 +0800

    GdkGLContext: Drop gdk_gl_context_has_[framebuffer_blit|frame_terminator]()
    
    gdk_gl_context_has_framebuffer_blit() and gdk_gl_context_has_frame_terminator()
    were only used by by GDK/Win32, and they do not provide performance advantages
    in GTK master, so clean up the code a bit by dropping them.

 gdk/gdkglcontext.c             | 36 -------------------------
 gdk/gdkglcontextprivate.h      |  2 --
 gdk/win32/gdkglcontext-win32.c | 60 ++----------------------------------------
 3 files changed, 2 insertions(+), 96 deletions(-)
---
diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index a7284b27c6..4dc06cc24c 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -107,8 +107,6 @@ typedef struct {
 
   guint realized : 1;
   guint use_texture_rectangle : 1;
-  guint has_gl_framebuffer_blit : 1;
-  guint has_frame_terminator : 1;
   guint has_khr_debug : 1;
   guint use_khr_debug : 1;
   guint has_unpack_subimage : 1;
@@ -427,22 +425,6 @@ gdk_gl_context_use_texture_rectangle (GdkGLContext *context)
   return priv->use_texture_rectangle;
 }
 
-gboolean
-gdk_gl_context_has_framebuffer_blit (GdkGLContext *context)
-{
-  GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context);
-
-  return priv->has_gl_framebuffer_blit;
-}
-
-gboolean
-gdk_gl_context_has_frame_terminator (GdkGLContext *context)
-{
-  GdkGLContextPrivate *priv = gdk_gl_context_get_instance_private (context);
-
-  return priv->has_frame_terminator;
-}
-
 void
 gdk_gl_context_push_debug_group (GdkGLContext *context,
                                  const char   *message)
@@ -997,18 +979,6 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
       has_npot = priv->gl_version >= 20;
       has_texture_rectangle = FALSE;
 
-      /* This should check for GL_NV_framebuffer_blit as well - see extension at:
-       *
-       * https://www.khronos.org/registry/gles/extensions/NV/NV_framebuffer_blit.txt
-       *
-       * for ANGLE, we can enable bit blitting if we have the
-       * GL_ANGLE_framebuffer_blit extension
-       */
-      priv->has_gl_framebuffer_blit = epoxy_has_gl_extension ("GL_ANGLE_framebuffer_blit");
-
-      /* No OES version */
-      priv->has_frame_terminator = FALSE;
-
       priv->has_unpack_subimage = epoxy_has_gl_extension ("GL_EXT_unpack_subimage");
       priv->has_khr_debug = epoxy_has_gl_extension ("GL_KHR_debug");
     }
@@ -1017,8 +987,6 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
       has_npot = priv->gl_version >= 20 || epoxy_has_gl_extension ("GL_ARB_texture_non_power_of_two");
       has_texture_rectangle = priv->gl_version >= 31 || epoxy_has_gl_extension ("GL_ARB_texture_rectangle");
 
-      priv->has_gl_framebuffer_blit = priv->gl_version >= 30 || epoxy_has_gl_extension 
("GL_EXT_framebuffer_blit");
-      priv->has_frame_terminator = epoxy_has_gl_extension ("GL_GREMEDY_frame_terminator");
       priv->has_unpack_subimage = TRUE;
       priv->has_khr_debug = epoxy_has_gl_extension ("GL_KHR_debug");
 
@@ -1052,8 +1020,6 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
                        "* Extensions checked:\n"
                        " - GL_ARB_texture_non_power_of_two: %s\n"
                        " - GL_ARB_texture_rectangle: %s\n"
-                       " - GL_EXT_framebuffer_blit: %s\n"
-                       " - GL_GREMEDY_frame_terminator: %s\n"
                        " - GL_KHR_debug: %s\n"
                        "* Using texture rectangle: %s",
                        priv->use_es ? "OpenGL ES" : "OpenGL",
@@ -1062,8 +1028,6 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
                        glGetString (GL_SHADING_LANGUAGE_VERSION),
                        has_npot ? "yes" : "no",
                        has_texture_rectangle ? "yes" : "no",
-                       priv->has_gl_framebuffer_blit ? "yes" : "no",
-                       priv->has_frame_terminator ? "yes" : "no",
                        priv->has_khr_debug ? "yes" : "no",
                        priv->use_texture_rectangle ? "yes" : "no"));
 
diff --git a/gdk/gdkglcontextprivate.h b/gdk/gdkglcontextprivate.h
index bf2dbfa5ff..67fe1a825d 100644
--- a/gdk/gdkglcontextprivate.h
+++ b/gdk/gdkglcontextprivate.h
@@ -87,8 +87,6 @@ void                    gdk_gl_context_upload_texture           (GdkGLContext
                                                                  guint            texture_target);
 GdkGLContextPaintData * gdk_gl_context_get_paint_data           (GdkGLContext    *context);
 gboolean                gdk_gl_context_use_texture_rectangle    (GdkGLContext    *context);
-gboolean                gdk_gl_context_has_framebuffer_blit     (GdkGLContext    *context);
-gboolean                gdk_gl_context_has_frame_terminator     (GdkGLContext    *context);
 gboolean                gdk_gl_context_has_unpack_subimage      (GdkGLContext    *context);
 void                    gdk_gl_context_push_debug_group         (GdkGLContext    *context,
                                                                  const char      *message);
diff --git a/gdk/win32/gdkglcontext-win32.c b/gdk/win32/gdkglcontext-win32.c
index ed2165d3e2..625b13ff74 100644
--- a/gdk/win32/gdkglcontext-win32.c
+++ b/gdk/win32/gdkglcontext-win32.c
@@ -104,25 +104,6 @@ _gdk_win32_gl_context_dispose (GObject *gobject)
   G_OBJECT_CLASS (gdk_win32_gl_context_parent_class)->dispose (gobject);
 }
 
-static void
-gdk_gl_blit_region (GdkSurface *surface, cairo_region_t *region)
-{
-  int n_rects, i;
-  int scale = gdk_surface_get_scale_factor (surface);
-  int wh = gdk_surface_get_height (surface);
-  cairo_rectangle_int_t rect;
-
-  n_rects = cairo_region_num_rectangles (region);
-  for (i = 0; i < n_rects; i++)
-    {
-      cairo_region_get_rectangle (region, i, &rect);
-      glScissor (rect.x * scale, (wh - rect.y - rect.height) * scale, rect.width * scale, rect.height * 
scale);
-      glBlitFramebuffer (rect.x * scale, (wh - rect.y - rect.height) * scale, (rect.x + rect.width) * scale, 
(wh - rect.y) * scale,
-                         rect.x * scale, (wh - rect.y - rect.height) * scale, (rect.x + rect.width) * scale, 
(wh - rect.y) * scale,
-                         GL_COLOR_BUFFER_BIT, GL_NEAREST);
-    }
-}
-
 #ifdef GDK_WIN32_ENABLE_EGL
 static gboolean
 _get_is_egl_force_redraw (GdkSurface *surface)
@@ -188,24 +169,7 @@ gdk_win32_gl_context_end_frame (GdkDrawContext *draw_context,
             }
         }
 
-      if (cairo_region_contains_rectangle (painted, &whole_window) == CAIRO_REGION_OVERLAP_IN)
-        SwapBuffers (context_win32->gl_hdc);
-      else if (gdk_gl_context_has_framebuffer_blit (context))
-        {
-          glDrawBuffer(GL_FRONT);
-          glReadBuffer(GL_BACK);
-          gdk_gl_blit_region (surface, painted);
-          glDrawBuffer(GL_BACK);
-          glFlush();
-
-          if (gdk_gl_context_has_frame_terminator (context))
-            glFrameTerminatorGREMEDY ();
-        }
-      else
-        {
-          g_warning ("Need to swap whole buffer even thouigh not everything was redrawn. Expect artifacts.");
-          SwapBuffers (context_win32->gl_hdc);
-        }
+      SwapBuffers (context_win32->gl_hdc);
     }
 #ifdef GDK_WIN32_ENABLE_EGL
   else
@@ -224,15 +188,7 @@ gdk_win32_gl_context_end_frame (GdkDrawContext *draw_context,
           _reset_egl_force_redraw (surface);
         }
 
-      if (cairo_region_contains_rectangle (painted, &whole_window) == CAIRO_REGION_OVERLAP_IN || 
force_egl_redraw_all)
-        eglSwapBuffers (display->egl_disp, egl_surface);
-      else if (gdk_gl_context_has_framebuffer_blit (context))
-        gdk_gl_blit_region (surface, painted);
-      else
-        {
-          g_warning ("Need to swap whole buffer even thouigh not everything was redrawn. Expect artifacts.");
-          eglSwapBuffers (display->egl_disp, egl_surface);
-        }
+      eglSwapBuffers (display->egl_disp, egl_surface);
     }
 #endif
 }
@@ -249,18 +205,6 @@ gdk_win32_gl_context_begin_frame (GdkDrawContext *draw_context,
   gdk_win32_surface_handle_queued_move_resize (draw_context);
 
   GDK_DRAW_CONTEXT_CLASS (gdk_win32_gl_context_parent_class)->begin_frame (draw_context, update_area);
-  if (gdk_gl_context_get_shared_context (context))
-    return;
-
-  if (gdk_gl_context_has_framebuffer_blit (context))
-    return;
-
-  /* If nothing else is known, repaint everything so that the back
-     buffer is fully up-to-date for the swapbuffer */
-  cairo_region_union_rectangle (update_area, &(GdkRectangle) {
-                                                 0, 0,
-                                                 gdk_surface_get_width (surface),
-                                                 gdk_surface_get_height (surface) });
 }
 
 typedef struct