Revert "Delete CC."

cc/resources/layer_quad.cc

+// Copyright 2011 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/resources/layer_quad.h"
+
+#include "base/logging.h"
+#include "ui/gfx/geometry/quad_f.h"
+
+namespace cc {
+
+LayerQuad::Edge::Edge(const gfx::PointF& p, const gfx::PointF& q) {
+  if (p == q) {
+    degenerate_ = true;
+    return;
+  }
+  degenerate_ = false;
+  gfx::Vector2dF tangent(p.y() - q.y(), q.x() - p.x());
+  float cross2 = p.x() * q.y() - q.x() * p.y();
+
+  set(tangent.x(), tangent.y(), cross2);
+  scale(1.0f / tangent.Length());
+}
+
+gfx::PointF LayerQuad::Edge::Intersect(const LayerQuad::Edge& e) const {
+  DCHECK(!degenerate());
+  DCHECK(!e.degenerate());
+
+  return gfx::PointF((y() * e.z() - e.y() * z()) / (x() * e.y() - e.x() * y()),
+                     (x() * e.z() - e.x() * z()) / (e.x() * y() - x() * e.y()));
+}
+
+LayerQuad::LayerQuad(const gfx::QuadF& quad) {
+  // Create edges.
+  left_ = Edge(quad.p4(), quad.p1());
+  right_ = Edge(quad.p2(), quad.p3());
+  top_ = Edge(quad.p1(), quad.p2());
+  bottom_ = Edge(quad.p3(), quad.p4());
+
+  float sign = quad.IsCounterClockwise() ? -1 : 1;
+  left_.scale(sign);
+  right_.scale(sign);
+  top_.scale(sign);
+  bottom_.scale(sign);
+}
+
+LayerQuad::LayerQuad(const Edge& left,
+                     const Edge& top,
+                     const Edge& right,
+                     const Edge& bottom)
+    : left_(left),
+      top_(top),
+      right_(right),
+      bottom_(bottom) {}
+
+gfx::QuadF LayerQuad::ToQuadF() const {
+  size_t num_degenerate_edges = left_.degenerate() + right_.degenerate() +
+                                top_.degenerate() + bottom_.degenerate();
+  if (num_degenerate_edges > 1) {
+    return gfx::QuadF();
+  }
+
+  if (left_.degenerate()) {
+    return gfx::QuadF(top_.Intersect(bottom_), top_.Intersect(right_),
+                      right_.Intersect(bottom_), bottom_.Intersect(top_));
+  }
+  if (right_.degenerate()) {
+    return gfx::QuadF(left_.Intersect(top_), top_.Intersect(bottom_),
+                      bottom_.Intersect(top_), bottom_.Intersect(left_));
+  }
+  if (top_.degenerate()) {
+    return gfx::QuadF(left_.Intersect(right_), right_.Intersect(left_),
+                      right_.Intersect(bottom_), bottom_.Intersect(left_));
+  }
+  if (bottom_.degenerate()) {
+    return gfx::QuadF(left_.Intersect(top_), top_.Intersect(right_),
+                      right_.Intersect(left_), left_.Intersect(right_));
+  }
+  return gfx::QuadF(left_.Intersect(top_),
+                    top_.Intersect(right_),
+                    right_.Intersect(bottom_),
+                    bottom_.Intersect(left_));
+}
+
+void LayerQuad::ToFloatArray(float flattened[12]) const {
+  if (left_.degenerate()) {
+    flattened[0] = bottom_.x();
+    flattened[1] = bottom_.y();
+    flattened[2] = bottom_.z();
+  } else {
+    flattened[0] = left_.x();
+    flattened[1] = left_.y();
+    flattened[2] = left_.z();
+  }
+  if (top_.degenerate()) {
+    flattened[3] = left_.x();
+    flattened[4] = left_.y();
+    flattened[5] = left_.z();
+  } else {
+    flattened[3] = top_.x();
+    flattened[4] = top_.y();
+    flattened[5] = top_.z();
+  }
+  if (right_.degenerate()) {
+    flattened[6] = top_.x();
+    flattened[7] = top_.y();
+    flattened[8] = top_.z();
+  } else {
+    flattened[6] = right_.x();
+    flattened[7] = right_.y();
+    flattened[8] = right_.z();
+  }
+  if (bottom_.degenerate()) {
+    flattened[9] = right_.x();
+    flattened[10] = right_.y();
+    flattened[11] = right_.z();
+  } else {
+    flattened[9] = bottom_.x();
+    flattened[10] = bottom_.y();
+    flattened[11] = bottom_.z();
+  }
+}
+
+}  // namespace cc