WIP BSP Tree for 3D Layer Sorting

cc/quads/draw_polygon.h

+// 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.
+
+#ifndef CC_QUADS_DRAW_POLYGON_H_
+#define CC_QUADS_DRAW_POLYGON_H_
+
+#include <vector>
+
+#include "cc/base/math_util.h"
+#include "cc/output/bsp_compare_result.h"
+#include "cc/quads/draw_quad.h"
+#include "ui/gfx/point3_f.h"
+#include "ui/gfx/quad_f.h"
+#include "ui/gfx/vector3d_f.h"
+
+namespace cc {
+
+class DrawPolygon {
+ public:
+  DrawPolygon();
+  ~DrawPolygon();
+
+  DrawPolygon(DrawQuad* original_ref,
+              gfx::Point3F* in_points,
+              int num_vertices_in_polygon,
+              int draw_order_index = 0,
+              bool polygon_is_original = true);
+  DrawPolygon(const DrawPolygon& other);
+
+  DrawPolygon& operator=(const DrawPolygon& rhs);
+
+  bool Split(const DrawPolygon& splitter,
+             double plane_threshold,
+             scoped_ptr<DrawPolygon>* front,
+             scoped_ptr<DrawPolygon>* back);
+  float SignedPointDistance(const gfx::Point3F& point) const;
+  bool ApplyTransform(const gfx::Transform& transform);
+
+  std::vector<gfx::Point3F> points;
+  gfx::Vector3dF normal;
+  float area;
+  int order_index;
+  bool is_original;  // Has this been split yet or is it still intact?

[Ian Vollick, 2014/07/16 20:54:33]

Apologies if I just missed it, but where's this used?

[troyhildebrandt, 2014/07/18 21:48:27]

This is more for the rendering side of things, not seen in this patch. This flag
is true for all polygons that haven't undergone a split, and indicates that we
can call the original quad drawing code vs. the slightly more expensive custom
quad code.

+
+  // Checks polygon a against polygon b and returns which side it lies on, or
+  // whether it crosses (necessitating a split in the BSP tree).
+  static BspCompareResult SideCompare(const DrawPolygon& a,
+                                      const DrawPolygon& b,
+                                      float z_threshold);
+  float Area() const;
+  float SignedArea() const;
+  void ToQuads2D(std::vector<gfx::QuadF>* quads) const;
+  int NumPoints() { return points.size(); }
+  bool GetInverseTransform(gfx::Transform* transform) const;
+
+  // The pointer to the original quad, which gives us all the drawing info
+  // we need.
+  DrawQuad* original_ref;
+
+ private:
+  void CopyFrom(const DrawPolygon& rhs);
+};
+
+}  // namespace cc
+
+#endif  // CC_QUADS_DRAW_POLYGON_H_