LittleEngine/Transform.cpp at master · dacunni/LittleEngine · GitHub

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#include <cmath>
#include "Transform.h"

//
// Constructors
//

Transform::Transform()
{
    fwd.identity();
    rev.identity();
}

Transform::Transform( const Matrix4x4 & f, const Matrix4x4 & r)
:   fwd(f),
    rev(r)
{

}

// Destructors

Transform::~Transform()
{

}

//
// Helpers
//
Transform compose( const Transform & t1, const Transform & t2)
{
    Transform c;
    mult( t1.fwd, t2.fwd, c.fwd);
    mult( t2.rev, t1.rev, c.rev);
    return c;
}

// Create a rotation Transform from angle and axis
Transform makeRotation( float angle, const Vector4 & axis)
{
    float ca = std::cos( angle);
    float omca = 1.0f - ca;
    float sa = std::sin( angle);
    Transform t;
    Vector4 u = axis;
    u.normalize();

    t.fwd = Matrix4x4( ca + u.x * u.x * omca, u.x * u.y * omca - u.z * sa, u.x * u.z * omca + u.y * sa, 0.0,
                       u.y * u.x * omca + u.z * sa, ca + u.y * u.y * omca, u.y * u.z * omca - u.x * sa, 0.0,
                       u.z * u.x * omca - u.y * sa, u.z * u.y * omca + u.x * sa, ca + u.z * u.z * omca, 0.0,
                       0.0, 0.0, 0.0, 1.0);
    inverse( t.fwd, t.rev);

    return t;
}

// Create a translation Transform
Transform makeTranslation( const Vector4 & d)
{
    return Transform(Matrix4x4(1.0, 0.0, 0.0, d.x,
                               0.0, 1.0, 0.0, d.y,
                               0.0, 0.0, 1.0, d.z,
                               0.0, 0.0, 0.0, 1.0),
                     Matrix4x4(1.0, 0.0, 0.0, -d.x,
                               0.0, 1.0, 0.0, -d.y,
                               0.0, 0.0, 1.0, -d.z,
                               0.0, 0.0, 0.0, 1.0));
}

// Create a translation Transform
Transform makeTranslation( float dx, float dy, float dz)
{
    return Transform(Matrix4x4(1.0, 0.0, 0.0, dx,
                               0.0, 1.0, 0.0, dy,
                               0.0, 0.0, 1.0, dz,
                               0.0, 0.0, 0.0, 1.0),
                     Matrix4x4(1.0, 0.0, 0.0, -dx,
                               0.0, 1.0, 0.0, -dy,
                               0.0, 0.0, 1.0, -dz,
                               0.0, 0.0, 0.0, 1.0));
}


// Create a scaling Transform
Transform makeScaling( float xScale, float yScale, float zScale)
{
    return Transform(Matrix4x4(xScale,  0.0,    0.0,    0.0,
                               0.0,     yScale, 0.0,    0.0,
                               0.0,     0.0,    zScale, 0.0,
                               0.0,     0.0,    0.0,    1.0),
                     Matrix4x4(1.0 / xScale, 0.0,          0.0,          0.0,
                               0.0,          1.0 / yScale, 0.0,          0.0,
                               0.0,          0.0,          1.0 / zScale, 0.0,
                               0.0,          0.0,          0.0,          1.0));
}

Transform makeScaling( float scale)
{
    return makeScaling( scale, scale, scale);
}