Experimental feature, which may make the Clipper offsets run faster
due to avoiding the 128bit multiply operations: A filtered predicate is tried to calculate SlopesEqual() to minimize the invocation of 128bit multiply operations.
This commit is contained in:
bubnikv
parent
bd93d2f334
commit
40a882d01e
@ -130,67 +130,37 @@ bool PolyNode::IsHole() const
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}
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//------------------------------------------------------------------------------
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#ifndef use_int32
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//------------------------------------------------------------------------------
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// Int128 class (enables safe math on signed 64bit integers)
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// eg Int128 val1((long64)9223372036854775807); //ie 2^63 -1
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// Int128 val2((long64)9223372036854775807);
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// eg Int128 val1((int64_t)9223372036854775807); //ie 2^63 -1
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// Int128 val2((int64_t)9223372036854775807);
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// Int128 val3 = val1 * val2;
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// val3.AsString => "85070591730234615847396907784232501249" (8.5e+37)
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//------------------------------------------------------------------------------
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// Used by the SlopesEqual() functions.
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class Int128
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{
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public:
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ulong64 lo;
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long64 hi;
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uint64_t lo;
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int64_t hi;
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Int128(long64 _lo = 0)
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{
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lo = (ulong64)_lo;
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if (_lo < 0) hi = -1; else hi = 0;
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}
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Int128(const Int128 &val): lo(val.lo), hi(val.hi){}
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Int128(const long64& _hi, const ulong64& _lo): lo(_lo), hi(_hi){}
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Int128(int64_t _lo = 0) : lo((uint64_t)_lo), hi((_lo < 0) ? -1 : 0) {}
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Int128(const Int128 &val) : lo(val.lo), hi(val.hi) {}
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Int128(const int64_t& _hi, const uint64_t& _lo) : lo(_lo), hi(_hi) {}
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Int128& operator = (const long64 &val)
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Int128& operator = (const int64_t &val)
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{
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lo = (ulong64)val;
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if (val < 0) hi = -1; else hi = 0;
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lo = (uint64_t)val;
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hi = (val < 0) ? -1 : 0;
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return *this;
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}
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bool operator == (const Int128 &val) const
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{return (hi == val.hi && lo == val.lo);}
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bool operator != (const Int128 &val) const
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{ return !(*this == val);}
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bool operator > (const Int128 &val) const
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{
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if (hi != val.hi)
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return hi > val.hi;
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else
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return lo > val.lo;
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}
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bool operator < (const Int128 &val) const
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{
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if (hi != val.hi)
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return hi < val.hi;
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else
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return lo < val.lo;
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}
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bool operator >= (const Int128 &val) const
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{ return !(*this < val);}
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bool operator <= (const Int128 &val) const
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{ return !(*this > val);}
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bool operator == (const Int128 &val) const { return hi == val.hi && lo == val.lo; }
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bool operator != (const Int128 &val) const { return ! (*this == val); }
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bool operator > (const Int128 &val) const { return (hi == val.hi) ? lo > val.lo : hi > val.hi; }
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bool operator < (const Int128 &val) const { return (hi == val.hi) ? lo < val.lo : hi < val.hi; }
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bool operator >= (const Int128 &val) const { return ! (*this < val); }
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bool operator <= (const Int128 &val) const { return ! (*this > val); }
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Int128& operator += (const Int128 &rhs)
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{
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@ -220,58 +190,47 @@ class Int128
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return result;
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}
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Int128 operator-() const //unary negation
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{
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if (lo == 0)
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return Int128(-hi, 0);
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else
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return Int128(~hi, ~lo + 1);
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}
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Int128 operator-() const { return (lo == 0) ? Int128(-hi, 0) : Int128(~hi, ~lo + 1); }
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operator double() const
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{
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const double shift64 = 18446744073709551616.0; //2^64
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if (hi < 0)
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{
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if (lo == 0) return (double)hi * shift64;
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else return -(double)(~lo + ~hi * shift64);
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}
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else
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return (double)(lo + hi * shift64);
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return (hi < 0) ?
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((lo == 0) ?
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(double)hi * shift64 :
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-(double)(~lo + ~hi * shift64)) :
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(double)(lo + hi * shift64);
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}
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static inline Int128 Multiply(int64_t lhs, int64_t rhs)
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{
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bool negate = (lhs < 0) != (rhs < 0);
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if (lhs < 0) lhs = -lhs;
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uint64_t int1Hi = uint64_t(lhs) >> 32;
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uint64_t int1Lo = uint64_t(lhs & 0xFFFFFFFF);
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if (rhs < 0) rhs = -rhs;
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uint64_t int2Hi = uint64_t(rhs) >> 32;
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uint64_t int2Lo = uint64_t(rhs & 0xFFFFFFFF);
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//because the high (sign) bits in both int1Hi & int2Hi have been zeroed,
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//there's no risk of 64 bit overflow in the following assignment
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//(ie: $7FFFFFFF*$FFFFFFFF + $7FFFFFFF*$FFFFFFFF < 64bits)
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uint64_t a = int1Hi * int2Hi;
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uint64_t b = int1Lo * int2Lo;
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//Result = A shl 64 + C shl 32 + B ...
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uint64_t c = int1Hi * int2Lo + int1Lo * int2Hi;
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Int128 tmp;
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tmp.hi = int64_t(a + (c >> 32));
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tmp.lo = int64_t(c << 32);
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tmp.lo += int64_t(b);
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if (tmp.lo < b) tmp.hi++;
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if (negate) tmp = -tmp;
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return tmp;
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}
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};
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//------------------------------------------------------------------------------
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inline Int128 Int128Mul (long64 lhs, long64 rhs)
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{
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bool negate = (lhs < 0) != (rhs < 0);
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if (lhs < 0) lhs = -lhs;
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ulong64 int1Hi = ulong64(lhs) >> 32;
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ulong64 int1Lo = ulong64(lhs & 0xFFFFFFFF);
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if (rhs < 0) rhs = -rhs;
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ulong64 int2Hi = ulong64(rhs) >> 32;
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ulong64 int2Lo = ulong64(rhs & 0xFFFFFFFF);
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//because the high (sign) bits in both int1Hi & int2Hi have been zeroed,
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//there's no risk of 64 bit overflow in the following assignment
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//(ie: $7FFFFFFF*$FFFFFFFF + $7FFFFFFF*$FFFFFFFF < 64bits)
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ulong64 a = int1Hi * int2Hi;
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ulong64 b = int1Lo * int2Lo;
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//Result = A shl 64 + C shl 32 + B ...
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ulong64 c = int1Hi * int2Lo + int1Lo * int2Hi;
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Int128 tmp;
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tmp.hi = long64(a + (c >> 32));
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tmp.lo = long64(c << 32);
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tmp.lo += long64(b);
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if (tmp.lo < b) tmp.hi++;
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if (negate) tmp = -tmp;
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return tmp;
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};
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#endif
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//------------------------------------------------------------------------------
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// Miscellaneous global functions
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@ -330,11 +289,8 @@ int PointInPolygon(const IntPoint &pt, const Path &path)
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for(size_t i = 1; i <= cnt; ++i)
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{
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IntPoint ipNext = (i == cnt ? path[0] : path[i]);
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if (ipNext.Y == pt.Y)
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{
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if ((ipNext.X == pt.X) || (ip.Y == pt.Y &&
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((ipNext.X > pt.X) == (ip.X < pt.X)))) return -1;
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}
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if (ipNext.Y == pt.Y && ((ipNext.X == pt.X) || (ip.Y == pt.Y && ((ipNext.X > pt.X) == (ip.X < pt.X)))))
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return -1;
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if ((ip.Y < pt.Y) != (ipNext.Y < pt.Y))
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{
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if (ip.X >= pt.X)
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@ -342,8 +298,7 @@ int PointInPolygon(const IntPoint &pt, const Path &path)
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if (ipNext.X > pt.X) result = 1 - result;
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else
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{
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double d = (double)(ip.X - pt.X) * (ipNext.Y - pt.Y) -
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(double)(ipNext.X - pt.X) * (ip.Y - pt.Y);
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double d = (double)(ip.X - pt.X) * (ipNext.Y - pt.Y) - (double)(ipNext.X - pt.X) * (ip.Y - pt.Y);
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if (!d) return -1;
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if ((d > 0) == (ipNext.Y > ip.Y)) result = 1 - result;
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}
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@ -351,8 +306,7 @@ int PointInPolygon(const IntPoint &pt, const Path &path)
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{
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if (ipNext.X > pt.X)
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{
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double d = (double)(ip.X - pt.X) * (ipNext.Y - pt.Y) -
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(double)(ipNext.X - pt.X) * (ip.Y - pt.Y);
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double d = (double)(ip.X - pt.X) * (ipNext.Y - pt.Y) - (double)(ipNext.X - pt.X) * (ip.Y - pt.Y);
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if (!d) return -1;
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if ((d > 0) == (ipNext.Y > ip.Y)) result = 1 - result;
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}
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@ -384,8 +338,7 @@ int PointInPolygon (const IntPoint &pt, OutPt *op)
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if (op->Next->Pt.X > pt.X) result = 1 - result;
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else
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{
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double d = (double)(op->Pt.X - pt.X) * (op->Next->Pt.Y - pt.Y) -
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(double)(op->Next->Pt.X - pt.X) * (op->Pt.Y - pt.Y);
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double d = (double)(op->Pt.X - pt.X) * (op->Next->Pt.Y - pt.Y) - (double)(op->Next->Pt.X - pt.X) * (op->Pt.Y - pt.Y);
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if (!d) return -1;
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if ((d > 0) == (op->Next->Pt.Y > op->Pt.Y)) result = 1 - result;
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}
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@ -393,8 +346,7 @@ int PointInPolygon (const IntPoint &pt, OutPt *op)
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{
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if (op->Next->Pt.X > pt.X)
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{
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double d = (double)(op->Pt.X - pt.X) * (op->Next->Pt.Y - pt.Y) -
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(double)(op->Next->Pt.X - pt.X) * (op->Pt.Y - pt.Y);
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double d = (double)(op->Pt.X - pt.X) * (op->Next->Pt.Y - pt.Y) - (double)(op->Next->Pt.X - pt.X) * (op->Pt.Y - pt.Y);
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if (!d) return -1;
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if ((d > 0) == (op->Next->Pt.Y > op->Pt.Y)) result = 1 - result;
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}
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@ -423,39 +375,43 @@ bool Poly2ContainsPoly1(OutPt *OutPt1, OutPt *OutPt2)
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}
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//----------------------------------------------------------------------
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// Approximate calculation of SlopesEqual() for "UseFullInt64Range"
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// Returns true if the slopes are unequal for sure,
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// otherwise returns false if the slopes may or may not be equal.
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inline bool SlopesUnequalFilter(cInt dx1, cInt dy1, cInt dx2, cInt dy2) {
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// Round dx1, dy1, dx2, dy2 to 31 bits.
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dx1 = (dx1 + (1 << 30)) >> 32;
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dy1 = (dy1 + (1 << 30)) >> 32;
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dx2 = (dx2 + (1 << 30)) >> 32;
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dy2 = (dy2 + (1 << 30)) >> 32;
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// Result fits 63 bits, it is an approximate of the determinant divided by 2^64.
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cInt discr = std::abs(dy1 * dx2 - dx1 * dy2);
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// Maximum absolute of the remainder of the exact determinant, divided by 2^64.
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cInt error = ((std::abs(dx1) + std::abs(dy1) + std::abs(dx2) + std::abs(dy2)) >> 1) + 1;
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return discr > error;
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}
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inline bool SlopesEqual(const cInt dx1, const cInt dy1, const cInt dx2, const cInt dy2, bool UseFullInt64Range) {
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return (UseFullInt64Range) ?
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// |dx1| < 2^63, |dx2| < 2^63 etc,
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#if 1
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// Instead of jumping to 128bit multiply on a 32bit or 64bit CPU,
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// calculate an approximate value of the determinant and its error.
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// If the determinant is above the error, the slopes are certainly not equal.
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! SlopesUnequalFilter(dx1, dy1, dx2, dy2) &&
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#endif
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Int128::Multiply(dy1, dx2) == Int128::Multiply(dx1, dy2) :
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// |dx1| < 2^31, |dx2| < 2^31 etc,
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// therefore the following computation could be done with 64bit arithmetics.
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dy1 * dx2 == dx1 * dy2;
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}
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inline bool SlopesEqual(const TEdge &e1, const TEdge &e2, bool UseFullInt64Range)
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{
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#ifndef use_int32
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if (UseFullInt64Range)
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return Int128Mul(e1.Delta.Y, e2.Delta.X) == Int128Mul(e1.Delta.X, e2.Delta.Y);
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else
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#endif
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return e1.Delta.Y * e2.Delta.X == e1.Delta.X * e2.Delta.Y;
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}
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//------------------------------------------------------------------------------
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{ return SlopesEqual(e1.Delta.X, e1.Delta.Y, e2.Delta.X, e2.Delta.Y, UseFullInt64Range); }
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inline bool SlopesEqual(const IntPoint &pt1, const IntPoint &pt2, const IntPoint &pt3, bool UseFullInt64Range)
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{ return SlopesEqual(pt1.X-pt2.X, pt1.Y-pt2.Y, pt2.X-pt3.X, pt2.Y-pt3.Y, UseFullInt64Range); }
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inline bool SlopesEqual(const IntPoint &pt1, const IntPoint &pt2, const IntPoint &pt3, const IntPoint &pt4, bool UseFullInt64Range)
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{ return SlopesEqual(pt1.X-pt2.X, pt1.Y-pt2.Y, pt3.X-pt4.X, pt3.Y-pt4.Y, UseFullInt64Range); }
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inline bool SlopesEqual(const IntPoint &pt1, const IntPoint &pt2,
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const IntPoint &pt3, bool UseFullInt64Range)
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{
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#ifndef use_int32
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if (UseFullInt64Range)
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return Int128Mul(pt1.Y-pt2.Y, pt2.X-pt3.X) == Int128Mul(pt1.X-pt2.X, pt2.Y-pt3.Y);
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else
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#endif
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return (pt1.Y-pt2.Y)*(pt2.X-pt3.X) == (pt1.X-pt2.X)*(pt2.Y-pt3.Y);
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}
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//------------------------------------------------------------------------------
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inline bool SlopesEqual(const IntPoint &pt1, const IntPoint &pt2,
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const IntPoint &pt3, const IntPoint &pt4, bool UseFullInt64Range)
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{
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#ifndef use_int32
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if (UseFullInt64Range)
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return Int128Mul(pt1.Y-pt2.Y, pt3.X-pt4.X) == Int128Mul(pt1.X-pt2.X, pt3.Y-pt4.Y);
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else
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#endif
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return (pt1.Y-pt2.Y)*(pt3.X-pt4.X) == (pt1.X-pt2.X)*(pt3.Y-pt4.Y);
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}
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//------------------------------------------------------------------------------
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inline bool IsHorizontal(TEdge &e)
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@ -473,8 +429,9 @@ inline double GetDx(const IntPoint &pt1, const IntPoint &pt2)
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inline cInt TopX(TEdge &edge, const cInt currentY)
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{
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return ( currentY == edge.Top.Y ) ?
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edge.Top.X : edge.Bot.X + Round(edge.Dx *(currentY - edge.Bot.Y));
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return (currentY == edge.Top.Y) ?
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edge.Top.X :
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edge.Bot.X + Round(edge.Dx *(currentY - edge.Bot.Y));
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}
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//------------------------------------------------------------------------------
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@ -519,10 +476,9 @@ void IntersectPoint(TEdge &Edge1, TEdge &Edge2, IntPoint &ip)
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b2 = Edge2.Bot.X - Edge2.Bot.Y * Edge2.Dx;
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double q = (b2-b1) / (Edge1.Dx - Edge2.Dx);
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ip.Y = Round(q);
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if (std::fabs(Edge1.Dx) < std::fabs(Edge2.Dx))
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ip.X = Round(Edge1.Dx * q + b1);
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else
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ip.X = Round(Edge2.Dx * q + b2);
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ip.X = (std::fabs(Edge1.Dx) < std::fabs(Edge2.Dx)) ?
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Round(Edge1.Dx * q + b1) :
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Round(Edge2.Dx * q + b2);
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}
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if (ip.Y < Edge1.Top.Y || ip.Y < Edge2.Top.Y)
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@ -34,11 +34,9 @@
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#ifndef clipper_hpp
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#define clipper_hpp
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#define CLIPPER_VERSION "6.2.6"
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#include <inttypes.h>
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//use_int32: When enabled 32bit ints are used instead of 64bit ints. This
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//improve performance but coordinate values are limited to the range +/- 46340
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//#define use_int32
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#define CLIPPER_VERSION "6.2.6"
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//use_xyz: adds a Z member to IntPoint. Adds a minor cost to perfomance.
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//#define use_xyz
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@ -68,18 +66,12 @@ enum PolyType { ptSubject, ptClip };
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//see http://glprogramming.com/red/chapter11.html
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enum PolyFillType { pftEvenOdd, pftNonZero, pftPositive, pftNegative };
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#ifdef use_int32
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typedef int cInt;
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static cInt const loRange = 0x7FFF;
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static cInt const hiRange = 0x7FFF;
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#else
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typedef signed long long cInt;
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static cInt const loRange = 0x3FFFFFFF;
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static cInt const hiRange = 0x3FFFFFFFFFFFFFFFLL;
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typedef signed long long long64; //used by Int128 class
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typedef unsigned long long ulong64;
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#endif
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// Point coordinate type
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typedef int64_t cInt;
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// Maximum cInt value to allow a cross product calculation using 32bit expressions.
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static cInt const loRange = 0x3FFFFFFF;
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// Maximum allowed cInt value.
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static cInt const hiRange = 0x3FFFFFFFFFFFFFFFLL;
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struct IntPoint {
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cInt X;
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@ -262,12 +254,11 @@ enum EdgeSide { esLeft = 1, esRight = 2};
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};
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// Point of an output polygon.
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// 36B on 64bit system with not use_int32 and not use_xyz.
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// 36B on 64bit system without use_xyz.
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struct OutPt {
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// 4B
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int Idx;
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// 8B (if use_int32 and not use_xyz) or 16B (if not use_int32 and not use_xyz)
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// or 12B (if use_int32 and use_xyz) or 24B (if not use_int32 and use_xyz)
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// 16B without use_xyz / 24B with use_xyz
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IntPoint Pt;
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// 4B on 32bit system, 8B on 64bit system
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OutPt *Next;
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@ -15,7 +15,9 @@ using ClipperLib::jtSquare;
|
||||
// Factor to convert from coord_t (which is int32) to an int64 type used by the Clipper library
|
||||
// for general offsetting (the offset(), offset2(), offset_ex() functions) and for the safety offset,
|
||||
// which is optionally executed by other functions (union, intersection, diff).
|
||||
// This scaling (cca 130t) is applied over the usual SCALING_FACTOR.
|
||||
// By the way, is the scalling for offset needed at all?
|
||||
// The reason to apply this scaling may be to match the resolution of the double mantissa.
|
||||
#define CLIPPER_OFFSET_POWER_OF_2 17
|
||||
// 2^17=131072
|
||||
#define CLIPPER_OFFSET_SCALE (1 << CLIPPER_OFFSET_POWER_OF_2)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user