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7d89a42b56
SourceSDK mathlib port with light modifications. Renamed Vector to Vector3D (to avoid confusion with std::vector (declared as vector) and Vector2D/Vector4D).
51 lines
1.4 KiB
C++
51 lines
1.4 KiB
C++
//===== Copyright (c) 1996-2005, Valve Corporation, All rights reserved. ======//
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//
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// Purpose:
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//
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// $NoKeywords: $
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//=============================================================================//
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#include "core/stdafx.h"
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#include "mathlib/vector.h"
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#include "mathlib/mathlib.h"
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//-----------------------------------------------------------------------------
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// Purpose: Calculate the volume of a tetrahedron with these vertices
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// Input : p0 - points of tetrahedron
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// p1 -
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// p2 -
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// p3 -
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// Output : float (volume in units^3)
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//-----------------------------------------------------------------------------
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static float TetrahedronVolume(const Vector3D& p0, const Vector3D& p1, const Vector3D& p2, const Vector3D& p3)
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{
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Vector3D a, b, c, cross;
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float volume = 1.0f / 6.0f;
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a = p1 - p0;
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b = p2 - p0;
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c = p3 - p0;
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cross = CrossProduct(b, c);
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volume *= DotProduct(a, cross);
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if (volume < 0)
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return -volume;
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return volume;
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}
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//-----------------------------------------------------------------------------
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// Purpose: Calculate a triangle area with these vertices
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// Input : p0 - points of tetrahedron
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// p1 -
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// p2 -
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// Output : float (area)
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//-----------------------------------------------------------------------------
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static float TriangleArea(const Vector3D& p0, const Vector3D& p1, const Vector3D& p2)
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{
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Vector3D e0 = p1 - p0;
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Vector3D e1 = p2 - p0;
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Vector3D cross;
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CrossProduct(e0, e1, cross);
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return 0.5 * cross.Length();
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}
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