[gtk/wip/chergert/glproto: 477/493] add very simple snapshot comparison code

[Christian Hergert <chergert src gnome org>]

commit dbe10e9c1bd91d1130cfd78fb830ea9c35b9b7bb
Author: Christian Hergert <chergert redhat com>
Date:   Tue Feb 16 17:52:52 2021 -0800

    add very simple snapshot comparison code
    
    this just does about the simplest, non-interesting implementation of
    comparing snapshots.

 gsk/next/gskglcommandqueue.c | 87 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
---
diff --git a/gsk/next/gskglcommandqueue.c b/gsk/next/gskglcommandqueue.c
index 0d029006a7..3b6c2861cb 100644
--- a/gsk/next/gskglcommandqueue.c
+++ b/gsk/next/gskglcommandqueue.c
@@ -279,6 +279,93 @@ snapshot_uniforms (GskGLUniformState        *state,
   return count;
 }
 
+static inline gboolean
+snapshots_equal (GskGLCommandQueue *self,
+                 GskGLCommandBatch *first,
+                 GskGLCommandBatch *second)
+{
+  if (first->draw.bind_count != second->draw.bind_count ||
+      first->draw.uniform_count != second->draw.uniform_count)
+    return FALSE;
+
+  for (guint i = 0; i < first->draw.bind_count; i++)
+    {
+      const GskGLCommandBind *fb = &self->batch_binds.elements[first->draw.bind_offset+i];
+      const GskGLCommandBind *sb = &self->batch_binds.elements[second->draw.bind_offset+i];
+
+      if (fb->id != sb->id || fb->texture != sb->texture)
+        return FALSE;
+    }
+
+  for (guint i = 0; i < first->draw.uniform_count; i++)
+    {
+      const GskGLCommandUniform *fu = &self->batch_uniforms.elements[first->draw.uniform_offset+i];
+      const GskGLCommandUniform *su = &self->batch_uniforms.elements[second->draw.uniform_offset+i];
+      gconstpointer fdata;
+      gconstpointer sdata;
+      gsize len;
+
+      if (fu->info.format != su->info.format ||
+          fu->info.array_count != su->info.array_count)
+        return FALSE;
+
+      fdata = gsk_gl_uniform_state_get_uniform_data (self->uniforms, fu->info.offset);
+      sdata = gsk_gl_uniform_state_get_uniform_data (self->uniforms, su->info.offset);
+
+      switch (fu->info.format)
+        {
+        case GSK_GL_UNIFORM_FORMAT_1F:
+        case GSK_GL_UNIFORM_FORMAT_1FV:
+        case GSK_GL_UNIFORM_FORMAT_1I:
+        case GSK_GL_UNIFORM_FORMAT_TEXTURE:
+        case GSK_GL_UNIFORM_FORMAT_1UI:
+          len = 4;
+          break;
+
+        case GSK_GL_UNIFORM_FORMAT_2F:
+        case GSK_GL_UNIFORM_FORMAT_2FV:
+        case GSK_GL_UNIFORM_FORMAT_2I:
+          len = 8;
+          break;
+
+        case GSK_GL_UNIFORM_FORMAT_3F:
+        case GSK_GL_UNIFORM_FORMAT_3FV:
+        case GSK_GL_UNIFORM_FORMAT_3I:
+          len = 12;
+          break;
+
+        case GSK_GL_UNIFORM_FORMAT_4F:
+        case GSK_GL_UNIFORM_FORMAT_4FV:
+        case GSK_GL_UNIFORM_FORMAT_4I:
+          len = 16;
+          break;
+
+
+        case GSK_GL_UNIFORM_FORMAT_MATRIX:
+          len = sizeof (float) * 16;
+          break;
+
+        case GSK_GL_UNIFORM_FORMAT_ROUNDED_RECT:
+          len = sizeof (float) * 12;
+          break;
+
+        case GSK_GL_UNIFORM_FORMAT_COLOR:
+          len = sizeof (float) * 4;
+          break;
+
+        default:
+          g_assert_not_reached ();
+        }
+
+      len *= fu->info.array_count;
+
+      if (memcmp (fdata, sdata, len) != 0)
+        return FALSE;
+    }
+
+  return TRUE;
+}
+
 static void
 gsk_gl_command_queue_dispose (GObject *object)
 {