src/pathops/SkPathOpsTypes.h

/*
 * Copyright 2012 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#ifndef SkPathOpsTypes_DEFINED
#define SkPathOpsTypes_DEFINED

#include "include/core/SkPath.h"
#include "include/core/SkScalar.h"
#include "include/core/SkTypes.h"
#include "src/pathops/SkPathOpsDebug.h"

#include <cfloat>
#include <cmath>

enum SkPathOpsMask {
    kWinding_PathOpsMask = -1,
    kNo_PathOpsMask = 0,
    kEvenOdd_PathOpsMask = 1
};

class SkArenaAlloc;
class SkOpCoincidence;
class SkOpContour;
class SkOpContourHead;

enum class SkOpPhase : char {
    kNoChange,
    kIntersecting,
    kWalking,
    kFixWinding,
};

class SkOpGlobalState {
public:
    SkOpGlobalState(SkOpContourHead* head,
                    SkArenaAlloc* allocator SkDEBUGPARAMS(bool debugSkipAssert)
                    SkDEBUGPARAMS(const char* testName));

    enum {
        kMaxWindingTries = 10
    };

    bool allocatedOpSpan() const {
        return fAllocatedOpSpan;
    }

    SkArenaAlloc* allocator() {
        return fAllocator;
    }

    void bumpNested() {
        ++fNested;
    }

    void clearNested() {
        fNested = 0;
    }

    SkOpCoincidence* coincidence() {
        return fCoincidence;
    }

    SkOpContourHead* contourHead() {
        return fContourHead;
    }

#ifdef SK_DEBUG
    const class SkOpAngle* debugAngle(int id) const;
    const SkOpCoincidence* debugCoincidence() const;
    SkOpContour* debugContour(int id) const;
    const class SkOpPtT* debugPtT(int id) const;
#endif

    static bool DebugRunFail();

#ifdef SK_DEBUG
    const class SkOpSegment* debugSegment(int id) const;
    bool debugSkipAssert() const { return fDebugSkipAssert; }
    const class SkOpSpanBase* debugSpan(int id) const;
    const char* debugTestName() const { return fDebugTestName; }
#endif

#if DEBUG_T_SECT_LOOP_COUNT
    void debugAddLoopCount(SkIntersections* , const SkIntersectionHelper& ,
        const SkIntersectionHelper& );
    void debugDoYourWorst(SkOpGlobalState* );
    void debugLoopReport();
    void debugResetLoopCounts();
#endif

#if DEBUG_COINCIDENCE
    void debugSetCheckHealth(bool check) { fDebugCheckHealth = check; }
    bool debugCheckHealth() const { return fDebugCheckHealth; }
#endif

#if DEBUG_VALIDATE || DEBUG_COIN
    void debugSetPhase(const char* funcName  DEBUG_COIN_DECLARE_PARAMS()) const;
#endif

#if DEBUG_COIN
    void debugAddToCoinChangedDict();
    void debugAddToGlobalCoinDicts();
    SkPathOpsDebug::CoinDict* debugCoinChangedDict() { return &fCoinChangedDict; }
    const SkPathOpsDebug::CoinDictEntry& debugCoinDictEntry() const { return fCoinDictEntry; }

    static void DumpCoinDict();
#endif


    int nested() const {
        return fNested;
    }

#ifdef SK_DEBUG
    int nextAngleID() {
        return ++fAngleID;
    }

    int nextCoinID() {
        return ++fCoinID;
    }

    int nextContourID() {
        return ++fContourID;
    }

    int nextPtTID() {
        return ++fPtTID;
    }

    int nextSegmentID() {
        return ++fSegmentID;
    }

    int nextSpanID() {
        return ++fSpanID;
    }
#endif

    SkOpPhase phase() const {
        return fPhase;
    }

    void resetAllocatedOpSpan() {
        fAllocatedOpSpan = false;
    }

    void setAllocatedOpSpan() {
        fAllocatedOpSpan = true;
    }

    void setCoincidence(SkOpCoincidence* coincidence) {
        fCoincidence = coincidence;
    }

    void setContourHead(SkOpContourHead* contourHead) {
        fContourHead = contourHead;
    }

    void setPhase(SkOpPhase phase) {
        if (SkOpPhase::kNoChange == phase) {
            return;
        }
        SkASSERT(fPhase != phase);
        fPhase = phase;
    }

    // called in very rare cases where angles are sorted incorrectly -- signfies op will fail
    void setWindingFailed() {
        fWindingFailed = true;
    }

    bool windingFailed() const {
        return fWindingFailed;
    }

private:
    SkArenaAlloc* fAllocator;
    SkOpCoincidence* fCoincidence;
    SkOpContourHead* fContourHead;
    int fNested;
    bool fAllocatedOpSpan;
    bool fWindingFailed;
    SkOpPhase fPhase;
#ifdef SK_DEBUG
    const char* fDebugTestName;
    void* fDebugReporter;
    int fAngleID;
    int fCoinID;
    int fContourID;
    int fPtTID;
    int fSegmentID;
    int fSpanID;
    bool fDebugSkipAssert;
#endif
#if DEBUG_T_SECT_LOOP_COUNT
    int fDebugLoopCount[3];
    SkPath::Verb fDebugWorstVerb[6];
    SkPoint fDebugWorstPts[24];
    float fDebugWorstWeight[6];
#endif
#if DEBUG_COIN
    SkPathOpsDebug::CoinDict fCoinChangedDict;
    SkPathOpsDebug::CoinDict fCoinVisitedDict;
    SkPathOpsDebug::CoinDictEntry fCoinDictEntry;
    const char* fPreviousFuncName;
#endif
#if DEBUG_COINCIDENCE
    bool fDebugCheckHealth;
#endif
};

#ifdef SK_DEBUG
#if DEBUG_COINCIDENCE
#define SkOPASSERT(cond) SkASSERT((this->globalState() && \
        (this->globalState()->debugCheckHealth() || \
        this->globalState()->debugSkipAssert())) || (cond))
#else
#define SkOPASSERT(cond) SkASSERT((this->globalState() && \
        this->globalState()->debugSkipAssert()) || (cond))
#endif
#define SkOPOBJASSERT(obj, cond) SkASSERT((obj->globalState() && \
        obj->globalState()->debugSkipAssert()) || (cond))
#else
#define SkOPASSERT(cond)
#define SkOPOBJASSERT(obj, cond)
#endif

// Use Almost Equal when comparing coordinates. Use epsilon to compare T values.
bool AlmostEqualUlps(float a, float b);
inline bool AlmostEqualUlps(double a, double b) {
    return AlmostEqualUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool AlmostEqualUlpsNoNormalCheck(float a, float b);
inline bool AlmostEqualUlpsNoNormalCheck(double a, double b) {
    return AlmostEqualUlpsNoNormalCheck(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool AlmostEqualUlps_Pin(float a, float b);
inline bool AlmostEqualUlps_Pin(double a, double b) {
    return AlmostEqualUlps_Pin(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

// Use Almost Dequal when comparing should not special case denormalized values.
bool AlmostDequalUlps(float a, float b);
bool AlmostDequalUlps(double a, double b);

bool NotAlmostEqualUlps(float a, float b);
inline bool NotAlmostEqualUlps(double a, double b) {
    return NotAlmostEqualUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool NotAlmostEqualUlps_Pin(float a, float b);
inline bool NotAlmostEqualUlps_Pin(double a, double b) {
    return NotAlmostEqualUlps_Pin(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool NotAlmostDequalUlps(float a, float b);
inline bool NotAlmostDequalUlps(double a, double b) {
    return NotAlmostDequalUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

// Use Almost Bequal when comparing coordinates in conjunction with between.
bool AlmostBequalUlps(float a, float b);
inline bool AlmostBequalUlps(double a, double b) {
    return AlmostBequalUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool AlmostPequalUlps(float a, float b);
inline bool AlmostPequalUlps(double a, double b) {
    return AlmostPequalUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool RoughlyEqualUlps(float a, float b);
inline bool RoughlyEqualUlps(double a, double b) {
    return RoughlyEqualUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool AlmostLessUlps(float a, float b);
inline bool AlmostLessUlps(double a, double b) {
    return AlmostLessUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool AlmostLessOrEqualUlps(float a, float b);
inline bool AlmostLessOrEqualUlps(double a, double b) {
    return AlmostLessOrEqualUlps(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

bool AlmostBetweenUlps(float a, float b, float c);
inline bool AlmostBetweenUlps(double a, double b, double c) {
    return AlmostBetweenUlps(SkDoubleToScalar(a), SkDoubleToScalar(b), SkDoubleToScalar(c));
}

int UlpsDistance(float a, float b);
inline int UlpsDistance(double a, double b) {
    return UlpsDistance(SkDoubleToScalar(a), SkDoubleToScalar(b));
}

// FLT_EPSILON == 1.19209290E-07 == 1 / (2 ^ 23)
// DBL_EPSILON == 2.22045e-16
const double FLT_EPSILON_CUBED = FLT_EPSILON * FLT_EPSILON * FLT_EPSILON;
const double FLT_EPSILON_HALF = FLT_EPSILON / 2;
const double FLT_EPSILON_DOUBLE = FLT_EPSILON * 2;
const double FLT_EPSILON_ORDERABLE_ERR = FLT_EPSILON * 16;
const double FLT_EPSILON_SQUARED = FLT_EPSILON * FLT_EPSILON;
// Use a compile-time constant for FLT_EPSILON_SQRT to avoid initializers.
// A 17 digit constant guarantees exact results.
const double FLT_EPSILON_SQRT = 0.00034526697709225118; // sqrt(FLT_EPSILON);
const double FLT_EPSILON_INVERSE = 1 / FLT_EPSILON;
const double DBL_EPSILON_ERR = DBL_EPSILON * 4;  // FIXME: tune -- allow a few bits of error
const double DBL_EPSILON_SUBDIVIDE_ERR = DBL_EPSILON * 16;
const double ROUGH_EPSILON = FLT_EPSILON * 64;
const double MORE_ROUGH_EPSILON = FLT_EPSILON * 256;
const double WAY_ROUGH_EPSILON = FLT_EPSILON * 2048;
const double BUMP_EPSILON = FLT_EPSILON * 4096;

const SkScalar INVERSE_NUMBER_RANGE = FLT_EPSILON_ORDERABLE_ERR;

inline bool zero_or_one(double x) {
    return x == 0 || x == 1;
}

inline bool approximately_zero(double x) {
    return fabs(x) < FLT_EPSILON;
}

inline bool precisely_zero(double x) {
    return fabs(x) < DBL_EPSILON_ERR;
}

inline bool precisely_subdivide_zero(double x) {
    return fabs(x) < DBL_EPSILON_SUBDIVIDE_ERR;
}

inline bool approximately_zero(float x) {
    return fabs(x) < FLT_EPSILON;
}

inline bool approximately_zero_half(double x) {
    return fabs(x) < FLT_EPSILON_HALF;
}

inline bool approximately_zero_double(double x) {
    return fabs(x) < FLT_EPSILON_DOUBLE;
}

inline bool approximately_zero_orderable(double x) {
    return fabs(x) < FLT_EPSILON_ORDERABLE_ERR;
}

inline bool approximately_zero_squared(double x) {
    return fabs(x) < FLT_EPSILON_SQUARED;
}

inline bool approximately_zero_sqrt(double x) {
    return fabs(x) < FLT_EPSILON_SQRT;
}

inline bool roughly_zero(double x) {
    return fabs(x) < ROUGH_EPSILON;
}

inline bool approximately_zero_inverse(double x) {
    return fabs(x) > FLT_EPSILON_INVERSE;
}

inline bool approximately_zero_when_compared_to(double x, double y) {
    return x == 0 || fabs(x) < fabs(y * FLT_EPSILON);
}

inline bool precisely_zero_when_compared_to(double x, double y) {
    return x == 0 || fabs(x) < fabs(y * DBL_EPSILON);
}

inline bool roughly_zero_when_compared_to(double x, double y) {
    return x == 0 || fabs(x) < fabs(y * ROUGH_EPSILON);
}

// Use this for comparing Ts in the range of 0 to 1. For general numbers (larger and smaller) use
// AlmostEqualUlps instead.
inline bool approximately_equal(double x, double y) {
    return approximately_zero(x - y);
}

inline bool precisely_equal(double x, double y) {
    return precisely_zero(x - y);
}

inline bool precisely_subdivide_equal(double x, double y) {
    return precisely_subdivide_zero(x - y);
}

inline bool approximately_equal_half(double x, double y) {
    return approximately_zero_half(x - y);
}

inline bool approximately_equal_double(double x, double y) {
    return approximately_zero_double(x - y);
}

inline bool approximately_equal_orderable(double x, double y) {
    return approximately_zero_orderable(x - y);
}

inline bool approximately_equal_squared(double x, double y) {
    return approximately_equal(x, y);
}

inline bool approximately_greater(double x, double y) {
    return x - FLT_EPSILON >= y;
}

inline bool approximately_greater_double(double x, double y) {
    return x - FLT_EPSILON_DOUBLE >= y;
}

inline bool approximately_greater_orderable(double x, double y) {
    return x - FLT_EPSILON_ORDERABLE_ERR >= y;
}

inline bool approximately_greater_or_equal(double x, double y) {
    return x + FLT_EPSILON > y;
}

inline bool approximately_greater_or_equal_double(double x, double y) {
    return x + FLT_EPSILON_DOUBLE > y;
}

inline bool approximately_greater_or_equal_orderable(double x, double y) {
    return x + FLT_EPSILON_ORDERABLE_ERR > y;
}

inline bool approximately_lesser(double x, double y) {
    return x + FLT_EPSILON <= y;
}

inline bool approximately_lesser_double(double x, double y) {
    return x + FLT_EPSILON_DOUBLE <= y;
}

inline bool approximately_lesser_orderable(double x, double y) {
    return x + FLT_EPSILON_ORDERABLE_ERR <= y;
}

inline bool approximately_lesser_or_equal(double x, double y) {
    return x - FLT_EPSILON < y;
}

inline bool approximately_lesser_or_equal_double(double x, double y) {
    return x - FLT_EPSILON_DOUBLE < y;
}

inline bool approximately_lesser_or_equal_orderable(double x, double y) {
    return x - FLT_EPSILON_ORDERABLE_ERR < y;
}

inline bool approximately_greater_than_one(double x) {
    return x > 1 - FLT_EPSILON;
}

inline bool precisely_greater_than_one(double x) {
    return x > 1 - DBL_EPSILON_ERR;
}

inline bool approximately_less_than_zero(double x) {
    return x < FLT_EPSILON;
}

inline bool precisely_less_than_zero(double x) {
    return x < DBL_EPSILON_ERR;
}

inline bool approximately_negative(double x) {
    return x < FLT_EPSILON;
}

inline bool approximately_negative_orderable(double x) {
    return x < FLT_EPSILON_ORDERABLE_ERR;
}

inline bool precisely_negative(double x) {
    return x < DBL_EPSILON_ERR;
}

inline bool approximately_one_or_less(double x) {
    return x < 1 + FLT_EPSILON;
}

inline bool approximately_one_or_less_double(double x) {
    return x < 1 + FLT_EPSILON_DOUBLE;
}

inline bool approximately_positive(double x) {
    return x > -FLT_EPSILON;
}

inline bool approximately_positive_squared(double x) {
    return x > -(FLT_EPSILON_SQUARED);
}

inline bool approximately_zero_or_more(double x) {
    return x > -FLT_EPSILON;
}

inline bool approximately_zero_or_more_double(double x) {
    return x > -FLT_EPSILON_DOUBLE;
}

inline bool approximately_between_orderable(double a, double b, double c) {
    return a <= c
            ? approximately_negative_orderable(a - b) && approximately_negative_orderable(b - c)
            : approximately_negative_orderable(b - a) && approximately_negative_orderable(c - b);
}

inline bool approximately_between(double a, double b, double c) {
    return a <= c ? approximately_negative(a - b) && approximately_negative(b - c)
            : approximately_negative(b - a) && approximately_negative(c - b);
}

inline bool precisely_between(double a, double b, double c) {
    return a <= c ? precisely_negative(a - b) && precisely_negative(b - c)
            : precisely_negative(b - a) && precisely_negative(c - b);
}

// returns true if (a <= b <= c) || (a >= b >= c)
inline bool between(double a, double b, double c) {
    SkASSERT(((a <= b && b <= c) || (a >= b && b >= c)) == ((a - b) * (c - b) <= 0)
            || (precisely_zero(a) && precisely_zero(b) && precisely_zero(c)));
    return (a - b) * (c - b) <= 0;
}

inline bool roughly_equal(double x, double y) {
    return fabs(x - y) < ROUGH_EPSILON;
}

inline bool roughly_negative(double x) {
    return x < ROUGH_EPSILON;
}

inline bool roughly_between(double a, double b, double c) {
    return a <= c ? roughly_negative(a - b) && roughly_negative(b - c)
            : roughly_negative(b - a) && roughly_negative(c - b);
}

inline bool more_roughly_equal(double x, double y) {
    return fabs(x - y) < MORE_ROUGH_EPSILON;
}

inline SkPath::Verb SkPathOpsPointsToVerb(int points) {
    int verb = (1 << points) >> 1;
#ifdef SK_DEBUG
    switch (points) {
        case 0: SkASSERT(SkPath::kMove_Verb == verb); break;
        case 1: SkASSERT(SkPath::kLine_Verb == verb); break;
        case 2: SkASSERT(SkPath::kQuad_Verb == verb); break;
        case 3: SkASSERT(SkPath::kCubic_Verb == verb); break;
        default: SkDEBUGFAIL("should not be here");
    }
#endif
    return (SkPath::Verb)verb;
}

inline int SkPathOpsVerbToPoints(SkPath::Verb verb) {
    int points = (int) verb - (((int) verb + 1) >> 2);
#ifdef SK_DEBUG
    switch (verb) {
        case SkPath::kLine_Verb: SkASSERT(1 == points); break;
        case SkPath::kQuad_Verb: SkASSERT(2 == points); break;
        case SkPath::kConic_Verb: SkASSERT(2 == points); break;
        case SkPath::kCubic_Verb: SkASSERT(3 == points); break;
        default: SkDEBUGFAIL("should not get here");
    }
#endif
    return points;
}

inline double SkDInterp(double A, double B, double t) {
    return A + (B - A) * t;
}

/* Returns -1 if negative, 0 if zero, 1 if positive
*/
inline int SkDSign(double x) {
    return (x > 0) - (x < 0);
}

/* Returns 0 if negative, 1 if zero, 2 if positive
*/
inline int SKDSide(double x) {
    return (x > 0) + (x >= 0);
}

/* Returns 1 if negative, 2 if zero, 4 if positive
*/
inline int SkDSideBit(double x) {
    return 1 << SKDSide(x);
}

inline double SkPinT(double t) {
    return precisely_less_than_zero(t) ? 0 : precisely_greater_than_one(t) ? 1 : t;
}

#endif