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// 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
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