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/* Copyright (C) 2013 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_FIXED_VECTOR3D
#define INCLUDED_FIXED_VECTOR3D
#include "maths/Fixed.h"
#include "maths/Sqrt.h"
class CFixedVector3D
{
public:
fixed X, Y, Z;
CFixedVector3D() { }
CFixedVector3D(fixed X, fixed Y, fixed Z) : X(X), Y(Y), Z(Z) { }
/// Vector equality
bool operator==(const CFixedVector3D& v) const
{
return (X == v.X && Y == v.Y && Z == v.Z);
}
/// Vector inequality
bool operator!=(const CFixedVector3D& v) const
{
return (X != v.X || Y != v.Y || Z != v.Z);
}
/// Vector addition
CFixedVector3D operator+(const CFixedVector3D& v) const
{
return CFixedVector3D(X + v.X, Y + v.Y, Z + v.Z);
}
/// Vector subtraction
CFixedVector3D operator-(const CFixedVector3D& v) const
{
return CFixedVector3D(X - v.X, Y - v.Y, Z - v.Z);
}
/// Negation
CFixedVector3D operator-() const
{
return CFixedVector3D(-X, -Y, -Z);
}
/// Vector addition
CFixedVector3D& operator+=(const CFixedVector3D& v)
{
*this = *this + v;
return *this;
}
/// Vector subtraction
CFixedVector3D& operator-=(const CFixedVector3D& v)
{
*this = *this - v;
return *this;
}
/**
* Returns the length of the vector.
* Will not overflow if the result can be represented as type 'fixed'.
*/
fixed Length() const
{
// Do intermediate calculations with 64-bit ints to avoid overflows
i32 x = X.GetInternalValue();
i32 y = Y.GetInternalValue();
i32 z = Z.GetInternalValue();
u64 xx = (u64)FIXED_MUL_I64_I32_I32(x, x);
u64 yy = (u64)FIXED_MUL_I64_I32_I32(y, y);
u64 zz = (u64)FIXED_MUL_I64_I32_I32(z, z);
u64 t = xx + yy;
CheckUnsignedAdditionOverflow(t, xx, L"Overflow in CFixedVector3D::Length() part 1")
u64 d2 = t + zz;
CheckUnsignedAdditionOverflow(d2, t, L"Overflow in CFixedVector3D::Length() part 2")
u32 d = isqrt64(d2);
CheckU32CastOverflow(d, i32, L"Overflow in CFixedVector3D::Length() part 3")
fixed r;
r.SetInternalValue((i32)d);
return r;
}
/**
* Normalize the vector so that length is close to 1.
* If length is 0, does nothing.
*/
void Normalize()
{
fixed l = Length();
if (!l.IsZero())
{
X = X / l;
Y = Y / l;
Z = Z / l;
}
}
/**
* Normalize the vector so that length is close to n.
* If length is 0, does nothing.
*/
void Normalize(fixed n)
{
fixed l = Length();
if (!l.IsZero())
{
X = X.MulDiv(n, l);
Y = Y.MulDiv(n, l);
Z = Z.MulDiv(n, l);
}
}
/**
* Compute the cross product of this vector with another.
*/
CFixedVector3D Cross(const CFixedVector3D& v)
{
i64 y_vz = FIXED_MUL_I64_I32_I32(Y.GetInternalValue(), v.Z.GetInternalValue());
i64 z_vy = FIXED_MUL_I64_I32_I32(Z.GetInternalValue(), v.Y.GetInternalValue());
CheckSignedSubtractionOverflow(i64, y_vz, z_vy, L"Overflow in CFixedVector3D::Cross() part 1", L"Underflow in CFixedVector3D::Cross() part 1")
i64 x = y_vz - z_vy;
x >>= fixed::fract_bits;
i64 z_vx = FIXED_MUL_I64_I32_I32(Z.GetInternalValue(), v.X.GetInternalValue());
i64 x_vz = FIXED_MUL_I64_I32_I32(X.GetInternalValue(), v.Z.GetInternalValue());
CheckSignedSubtractionOverflow(i64, z_vx, x_vz, L"Overflow in CFixedVector3D::Cross() part 2", L"Underflow in CFixedVector3D::Cross() part 2")
i64 y = z_vx - x_vz;
y >>= fixed::fract_bits;
i64 x_vy = FIXED_MUL_I64_I32_I32(X.GetInternalValue(), v.Y.GetInternalValue());
i64 y_vx = FIXED_MUL_I64_I32_I32(Y.GetInternalValue(), v.X.GetInternalValue());
CheckSignedSubtractionOverflow(i64, x_vy, y_vx, L"Overflow in CFixedVector3D::Cross() part 3", L"Underflow in CFixedVector3D::Cross() part 3")
i64 z = x_vy - y_vx;
z >>= fixed::fract_bits;
CheckCastOverflow(x, i32, L"Overflow in CFixedVector3D::Cross() part 4", L"Underflow in CFixedVector3D::Cross() part 4")
CheckCastOverflow(y, i32, L"Overflow in CFixedVector3D::Cross() part 5", L"Underflow in CFixedVector3D::Cross() part 5")
CheckCastOverflow(z, i32, L"Overflow in CFixedVector3D::Cross() part 6", L"Underflow in CFixedVector3D::Cross() part 6")
CFixedVector3D ret;
ret.X.SetInternalValue((i32)x);
ret.Y.SetInternalValue((i32)y);
ret.Z.SetInternalValue((i32)z);
return ret;
}
/**
* Compute the dot product of this vector with another.
*/
fixed Dot(const CFixedVector3D& v)
{
i64 x = FIXED_MUL_I64_I32_I32(X.GetInternalValue(), v.X.GetInternalValue());
i64 y = FIXED_MUL_I64_I32_I32(Y.GetInternalValue(), v.Y.GetInternalValue());
i64 z = FIXED_MUL_I64_I32_I32(Z.GetInternalValue(), v.Z.GetInternalValue());
CheckSignedAdditionOverflow(i64, x, y, L"Overflow in CFixedVector3D::Dot() part 1", L"Underflow in CFixedVector3D::Dot() part 1")
i64 t = x + y;
CheckSignedAdditionOverflow(i64, t, z, L"Overflow in CFixedVector3D::Dot() part 2", L"Underflow in CFixedVector3D::Dot() part 2")
i64 sum = t + z;
sum >>= fixed::fract_bits;
CheckCastOverflow(sum, i32, L"Overflow in CFixedVector3D::Dot() part 3", L"Underflow in CFixedVector3D::Dot() part 3")
fixed ret;
ret.SetInternalValue((i32)sum);
return ret;
}
};
#endif // INCLUDED_FIXED_VECTOR3D
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