[gtk/wip/otte/for-main: 1/2] gltexture: Only use glGetFramebufferParameter() when available

[Benjamin Otte <otte src gnome org>]

commit 2c718253247b586ffb9e68e074bd7ef77e9e93f1
Author: Benjamin Otte <otte redhat com>
Date:   Tue Feb 8 01:32:44 2022 +0100

    gltexture: Only use glGetFramebufferParameter() when available
    
    Fixes #4678

 gdk/gdkgltexture.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/gdk/gdkgltexture.c b/gdk/gdkgltexture.c
index 40ccaf2add..23bc806c0d 100644
--- a/gdk/gdkgltexture.c
+++ b/gdk/gdkgltexture.c
@@ -175,10 +175,19 @@ gdk_gl_texture_do_download (gpointer texture_,
       glGenFramebuffers (1, &fbo);
       glBindFramebuffer (GL_FRAMEBUFFER, fbo);
       glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, self->id, 0);
-      glGetFramebufferParameteriv (GL_FRAMEBUFFER, GL_IMPLEMENTATION_COLOR_READ_FORMAT, &gl_read_format);
-      glGetFramebufferParameteriv (GL_FRAMEBUFFER, GL_IMPLEMENTATION_COLOR_READ_TYPE, &gl_read_type);
-      if (!gdk_gl_texture_find_format (gdk_gl_context_get_use_es (self->context), gl_read_format, 
gl_read_type, &actual_format))
-        actual_format = GDK_MEMORY_R8G8B8A8_PREMULTIPLIED; /* pray */
+      if (gdk_gl_context_check_version (self->context, 4, 3, 3, 1))
+        {
+          glGetFramebufferParameteriv (GL_FRAMEBUFFER, GL_IMPLEMENTATION_COLOR_READ_FORMAT, &gl_read_format);
+          glGetFramebufferParameteriv (GL_FRAMEBUFFER, GL_IMPLEMENTATION_COLOR_READ_TYPE, &gl_read_type);
+          if (!gdk_gl_texture_find_format (gdk_gl_context_get_use_es (self->context), gl_read_format, 
gl_read_type, &actual_format))
+            actual_format = GDK_MEMORY_R8G8B8A8_PREMULTIPLIED; /* pray */
+        }
+      else
+        {
+          gl_read_format = GL_RGBA;
+          gl_read_type = GL_UNSIGNED_BYTE;
+          actual_format = GDK_MEMORY_R8G8B8A8_PREMULTIPLIED;
+        }
 
       if (download->format == actual_format &&
           (download->stride == expected_stride))