1/*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
21 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26// Cubic curve classification algorithm from "Rendering Vector Art on
27// the GPU" by Loop and Blinn, GPU Gems 3, Chapter 25:
28// http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html .
29
30#ifndef LoopBlinnClassifier_h
31#define LoopBlinnClassifier_h
32
33#include <wtf/Noncopyable.h>
34
35namespace WebCore {
36
37class FloatPoint;
38
39// Classifies cubic curves into specific types.
40class LoopBlinnClassifier {
41    WTF_MAKE_NONCOPYABLE(LoopBlinnClassifier);
42public:
43    // The types of cubic curves.
44    enum CurveType {
45        kSerpentine,
46        kCusp,
47        kLoop,
48        kQuadratic,
49        kLine,
50        kPoint
51    };
52
53    // The result of the classifier.
54    struct Result {
55    public:
56        Result(CurveType inputCurveType, float inputD1, float inputD2, float inputD3)
57            : curveType(inputCurveType)
58            , d1(inputD1)
59            , d2(inputD2)
60            , d3(inputD3) { }
61
62        CurveType curveType;
63
64        // These are coefficients used later in the computation of
65        // texture coordinates per vertex.
66        float d1;
67        float d2;
68        float d3;
69    };
70
71    // Classifies the given cubic bezier curve starting at c0, ending
72    // at c3, and affected by control points c1 and c2.
73    static Result classify(const FloatPoint& c0,
74                           const FloatPoint& c1,
75                           const FloatPoint& c2,
76                           const FloatPoint& c3);
77
78private:
79    // This class does not need to be instantiated.
80    LoopBlinnClassifier() { }
81};
82
83} // namespace WebCore
84
85#endif // LoopBlinnClassifier_h
86