cogl-journal: Use a loose region instead of a bounding boxwip/journal-reorg

Instead of just recording the bounding box of a journal batch, it now
uses a new data type called a loose region. A loose region keeps track
of up to 4 separate bounding boxes to represent at least the region
covered by the batch. If a new rectangle added to the region only
increases the size of an existing bounding box to within a certain
threshold then it will be added to that bounding box, otherwise it
will start a new bounding box. This increases the chances that batches
can be grouped together because it can represent sparse regions to a
degree without as much of the complexity as totally accurately
tracking the region.

1 files changed, 64 insertions, 0 deletions

diff --git a/cogl/cogl-loose-region.h b/cogl/cogl-loose-region.h
new file mode 100644
index 00000000..b7296d44
--- /dev/null
+++ b/cogl/cogl-loose-region.h
@@ -0,0 +1,64 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2011 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ *
+ * Authors:
+ *   Neil Roberts <neil@linux.intel.com>
+ */
+
+/* CoglLooseRegion is a data structure that is a cross between a
+   simple bounding box and a region. Instead of keeping all of the
+   rectangles necessary to track an exact region, it only keeps around
+   a few bounding boxes. This can be checked for intersection much
+   more quickly than a complicated region but it will have some false
+   positives. */
+
+#ifndef __COGL_LOOSE_REGION_H__
+#define __COGL_LOOSE_REGION_H__
+
+#include <glib.h>
+
+#define COGL_LOOSE_REGION_N_RECTANGLES 4
+
+typedef struct _CoglLooseRegionRectangle
+{
+  float x_1, y_1;
+  float x_2, y_2;
+} CoglLooseRegionRectangle;
+
+typedef struct _CoglLooseRegion
+{
+  int n_rects;
+  CoglLooseRegionRectangle rects[COGL_LOOSE_REGION_N_RECTANGLES];
+} CoglLooseRegion;
+
+void
+_cogl_loose_region_init (CoglLooseRegion *region);
+
+void
+_cogl_loose_region_add_rectangle (CoglLooseRegion *region,
+                                  const CoglLooseRegionRectangle *rect);
+
+gboolean
+_cogl_loose_region_intersects (const CoglLooseRegion *region,
+                               const CoglLooseRegionRectangle *rect);
+
+#endif /* __COGL_LOOSE_REGION_H__ */