[gtk/wip/chergert/glproto] use inlined memcmp for rounded rect comparison

[Christian Hergert <chergert src gnome org>]

commit a3ca14ce403a79803e5f10460c6be718cc3d60b3
Author: Christian Hergert <chergert redhat com>
Date:   Wed Jan 27 20:24:10 2021 -0800

    use inlined memcmp for rounded rect comparison

 gsk/next/gskgluniformstate.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
---
diff --git a/gsk/next/gskgluniformstate.c b/gsk/next/gskgluniformstate.c
index f617e852e4..3728a10151 100644
--- a/gsk/next/gskgluniformstate.c
+++ b/gsk/next/gskgluniformstate.c
@@ -81,6 +81,24 @@ typedef struct
   guint   n_changed;
 } ProgramInfo;
 
+static inline gboolean
+rounded_rect_equal (const GskRoundedRect *r1,
+                    const GskRoundedRect *r2)
+{
+  /* Ensure we're dealing with tightly packed floats that
+   * should allow us to compare without any gaps using memcmp().
+   */
+  G_STATIC_ASSERT (sizeof *r1 == (sizeof (float) * 12));
+
+  if (r1 == r2)
+    return TRUE;
+
+  if (r1 == NULL)
+    return FALSE;
+
+  return memcmp (r1, r2, sizeof *r1) == 0;
+}
+
 GskGLUniformState *
 gsk_gl_uniform_state_new (void)
 {
@@ -514,7 +532,7 @@ gsk_gl_uniform_state_set_rounded_rect (GskGLUniformState    *state,
 
   if ((u = get_uniform (state, program, GSK_GL_UNIFORM_FORMAT_ROUNDED_RECT, 1, location, &info)))
     {
-      if (info->initial || !gsk_rounded_rect_equal (rounded_rect, u))
+      if (info->initial || !rounded_rect_equal (rounded_rect, u))
         {
           g_assert (!info->send_corners || info->changed);