WIP BSP Tree for 3D Layer Sorting

cc/output/bsp_controller.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#include "cc/output/bsp_compare_result.h"
+#include "cc/output/bsp_controller.h"
+#include "cc/quads/draw_polygon.h"
+#include "ui/gfx/vector3d_f.h"
+
+namespace cc {
+
+BspCompareResult BspController::GetNodePositionRelative(
+    const DrawPolygon& node_a,
+    const DrawPolygon& node_b) const {
+  return DrawPolygon::SideCompare(node_a, node_b, compare_threshold_);
+}
+
+// The base comparer with 0,0,0 as camera position facing forward
+ViewCompareResult BspController::GetCameraPositionRelative(
+    const DrawPolygon& node) const {
+  // The dot product figures out if we're behind or in front of the
+  // current DrawPolygon based on its normal and a point from it.
+  if (node.normal.z() >= 0.f)

[Ian Vollick, 2014/07/16 20:54:32]

This is probably a dumb question, but why don't you want (camera - point on
plane) DOT (normal) > 0?

[troyhildebrandt, 2014/07/18 21:48:25]

You're right, done.

+    return IN_FRONT;
+  return BEHIND;
+}
+
+bool BspController::SplitPolygon(scoped_ptr<DrawPolygon> polygon,
+                                 const DrawPolygon& splitter,
+                                 scoped_ptr<DrawPolygon>* front,
+                                 scoped_ptr<DrawPolygon>* back) const {
+  return polygon->Split(splitter, split_threshold_, front, back);
+}
+
+float BspController::SplitWeight(const DrawPolygon& polygon) {
+  return polygon.area;
+}
+
+}  // namespace cc