191 lines
5.4 KiB
C++
191 lines
5.4 KiB
C++
/* Copyright (C) 2010 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef INCLUDED_FIXED_VECTOR3D
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#define INCLUDED_FIXED_VECTOR3D
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#include "maths/Fixed.h"
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#include "maths/Sqrt.h"
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class CFixedVector3D
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{
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public:
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fixed X, Y, Z;
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CFixedVector3D() { }
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CFixedVector3D(fixed X, fixed Y, fixed Z) : X(X), Y(Y), Z(Z) { }
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/// Vector equality
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bool operator==(const CFixedVector3D& v) const
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{
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return (X == v.X && Y == v.Y && Z == v.Z);
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}
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/// Vector inequality
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bool operator!=(const CFixedVector3D& v) const
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{
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return (X != v.X || Y != v.Y || Z != v.Z);
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}
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/// Vector addition
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CFixedVector3D operator+(const CFixedVector3D& v) const
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{
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return CFixedVector3D(X + v.X, Y + v.Y, Z + v.Z);
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}
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/// Vector subtraction
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CFixedVector3D operator-(const CFixedVector3D& v) const
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{
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return CFixedVector3D(X - v.X, Y - v.Y, Z - v.Z);
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}
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/// Negation
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CFixedVector3D operator-() const
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{
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return CFixedVector3D(-X, -Y, -Z);
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}
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/// Vector addition
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CFixedVector3D& operator+=(const CFixedVector3D& v)
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{
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*this = *this + v;
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return *this;
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}
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/// Vector subtraction
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CFixedVector3D& operator-=(const CFixedVector3D& v)
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{
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*this = *this - v;
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return *this;
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}
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/**
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* Returns the length of the vector.
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* Will not overflow if the result can be represented as type 'fixed'.
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*/
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fixed Length() const
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{
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// Do intermediate calculations with 64-bit ints to avoid overflows
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i64 x = (i64)X.GetInternalValue();
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i64 y = (i64)Y.GetInternalValue();
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i64 z = (i64)Z.GetInternalValue();
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u64 xx = (u64)(x * x);
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u64 yy = (u64)(y * y);
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u64 zz = (u64)(z * z);
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u64 t = xx + yy;
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CheckUnsignedAdditionOverflow(t, xx, L"Overflow in CFixedVector3D::Length() part 1")
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u64 d2 = t + zz;
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CheckUnsignedAdditionOverflow(d2, t, L"Overflow in CFixedVector3D::Length() part 2")
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u32 d = isqrt64(d2);
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CheckU32CastOverflow(d, i32, L"Overflow in CFixedVector3D::Length() part 3")
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fixed r;
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r.SetInternalValue((i32)d);
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return r;
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}
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/**
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* Normalize the vector so that length is close to 1.
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* If length is 0, does nothing.
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*/
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void Normalize()
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{
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fixed l = Length();
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if (!l.IsZero())
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{
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X = X / l;
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Y = Y / l;
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Z = Z / l;
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}
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}
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/**
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* Normalize the vector so that length is close to n.
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* If length is 0, does nothing.
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*/
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void Normalize(fixed n)
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{
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fixed l = Length();
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if (!l.IsZero())
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{
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X = X.MulDiv(n, l);
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Y = Y.MulDiv(n, l);
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Z = Z.MulDiv(n, l);
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}
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}
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/**
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* Compute the cross product of this vector with another.
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*/
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CFixedVector3D Cross(const CFixedVector3D& v)
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{
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i64 y_vz = (i64)Y.GetInternalValue() * (i64)v.Z.GetInternalValue();
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i64 z_vy = (i64)Z.GetInternalValue() * (i64)v.Y.GetInternalValue();
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CheckSignedSubtractionOverflow(i64, y_vz, z_vy, L"Overflow in CFixedVector3D::Cross() part 1", L"Underflow in CFixedVector3D::Cross() part 1")
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i64 x = y_vz - z_vy;
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x >>= fixed::fract_bits;
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i64 z_vx = (i64)Z.GetInternalValue() * (i64)v.X.GetInternalValue();
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i64 x_vz = (i64)X.GetInternalValue() * (i64)v.Z.GetInternalValue();
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CheckSignedSubtractionOverflow(i64, z_vx, x_vz, L"Overflow in CFixedVector3D::Cross() part 2", L"Underflow in CFixedVector3D::Cross() part 2")
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i64 y = z_vx - x_vz;
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y >>= fixed::fract_bits;
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i64 x_vy = (i64)X.GetInternalValue() * (i64)v.Y.GetInternalValue();
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i64 y_vx = (i64)Y.GetInternalValue() * (i64)v.X.GetInternalValue();
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CheckSignedSubtractionOverflow(i64, x_vy, y_vx, L"Overflow in CFixedVector3D::Cross() part 3", L"Underflow in CFixedVector3D::Cross() part 3")
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i64 z = x_vy - y_vx;
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z >>= fixed::fract_bits;
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CheckCastOverflow(x, i32, L"Overflow in CFixedVector3D::Cross() part 4", L"Underflow in CFixedVector3D::Cross() part 4")
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CheckCastOverflow(y, i32, L"Overflow in CFixedVector3D::Cross() part 5", L"Underflow in CFixedVector3D::Cross() part 5")
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CheckCastOverflow(z, i32, L"Overflow in CFixedVector3D::Cross() part 6", L"Underflow in CFixedVector3D::Cross() part 6")
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CFixedVector3D ret;
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ret.X.SetInternalValue((i32)x);
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ret.Y.SetInternalValue((i32)y);
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ret.Z.SetInternalValue((i32)z);
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return ret;
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}
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/**
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* Compute the dot product of this vector with another.
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*/
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fixed Dot(const CFixedVector3D& v)
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{
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i64 x = (i64)X.GetInternalValue() * (i64)v.X.GetInternalValue();
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i64 y = (i64)Y.GetInternalValue() * (i64)v.Y.GetInternalValue();
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i64 z = (i64)Z.GetInternalValue() * (i64)v.Z.GetInternalValue();
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CheckSignedAdditionOverflow(i64, x, y, L"Overflow in CFixedVector3D::Dot() part 1", L"Underflow in CFixedVector3D::Dot() part 1")
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i64 t = x + y;
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CheckSignedAdditionOverflow(i64, t, z, L"Overflow in CFixedVector3D::Dot() part 2", L"Underflow in CFixedVector3D::Dot() part 2")
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i64 sum = t + z;
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sum >>= fixed::fract_bits;
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CheckCastOverflow(sum, i32, L"Overflow in CFixedVector3D::Dot() part 3", L"Underflow in CFixedVector3D::Dot() part 3")
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fixed ret;
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ret.SetInternalValue((i32)sum);
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return ret;
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}
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};
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#endif // INCLUDED_FIXED_VECTOR3D
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