BansheeEngine/BansheeUtility/Source/BsMatrix4.cpp

#include "BsMatrix4.h"

#include "BsVector3.h"
#include "BsMatrix3.h"
#include "BsQuaternion.h"

namespace BansheeEngine
{
    const Matrix4 Matrix4::ZERO(
        0.0f, 0.0f, 0.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 0.0f);

    const Matrix4 Matrix4::IDENTITY(
		1.0f, 0.0f, 0.0f, 0.0f,
		0.0f, 1.0f, 0.0f, 0.0f,
		0.0f, 0.0f, 1.0f, 0.0f,
		0.0f, 0.0f, 0.0f, 1.0f);

    static float MINOR(const Matrix4& m, const UINT32 r0, const UINT32 r1, const UINT32 r2, 
								const UINT32 c0, const UINT32 c1, const UINT32 c2)
    {
        return m[r0][c0] * (m[r1][c1] * m[r2][c2] - m[r2][c1] * m[r1][c2]) -
            m[r0][c1] * (m[r1][c0] * m[r2][c2] - m[r2][c0] * m[r1][c2]) +
            m[r0][c2] * (m[r1][c0] * m[r2][c1] - m[r2][c0] * m[r1][c1]);
    }

    Matrix4 Matrix4::adjoint() const
    {
        return Matrix4( MINOR(*this, 1, 2, 3, 1, 2, 3),
            -MINOR(*this, 0, 2, 3, 1, 2, 3),
            MINOR(*this, 0, 1, 3, 1, 2, 3),
            -MINOR(*this, 0, 1, 2, 1, 2, 3),

            -MINOR(*this, 1, 2, 3, 0, 2, 3),
            MINOR(*this, 0, 2, 3, 0, 2, 3),
            -MINOR(*this, 0, 1, 3, 0, 2, 3),
            MINOR(*this, 0, 1, 2, 0, 2, 3),

            MINOR(*this, 1, 2, 3, 0, 1, 3),
            -MINOR(*this, 0, 2, 3, 0, 1, 3),
            MINOR(*this, 0, 1, 3, 0, 1, 3),
            -MINOR(*this, 0, 1, 2, 0, 1, 3),

            -MINOR(*this, 1, 2, 3, 0, 1, 2),
            MINOR(*this, 0, 2, 3, 0, 1, 2),
            -MINOR(*this, 0, 1, 3, 0, 1, 2),
            MINOR(*this, 0, 1, 2, 0, 1, 2));
    }

    float Matrix4::determinant() const
    {
        return m[0][0] * MINOR(*this, 1, 2, 3, 1, 2, 3) -
            m[0][1] * MINOR(*this, 1, 2, 3, 0, 2, 3) +
            m[0][2] * MINOR(*this, 1, 2, 3, 0, 1, 3) -
            m[0][3] * MINOR(*this, 1, 2, 3, 0, 1, 2);
    }

    Matrix4 Matrix4::inverse() const
    {
        float m00 = m[0][0], m01 = m[0][1], m02 = m[0][2], m03 = m[0][3];
        float m10 = m[1][0], m11 = m[1][1], m12 = m[1][2], m13 = m[1][3];
        float m20 = m[2][0], m21 = m[2][1], m22 = m[2][2], m23 = m[2][3];
        float m30 = m[3][0], m31 = m[3][1], m32 = m[3][2], m33 = m[3][3];

        float v0 = m20 * m31 - m21 * m30;
        float v1 = m20 * m32 - m22 * m30;
        float v2 = m20 * m33 - m23 * m30;
        float v3 = m21 * m32 - m22 * m31;
        float v4 = m21 * m33 - m23 * m31;
        float v5 = m22 * m33 - m23 * m32;

        float t00 = + (v5 * m11 - v4 * m12 + v3 * m13);
        float t10 = - (v5 * m10 - v2 * m12 + v1 * m13);
        float t20 = + (v4 * m10 - v2 * m11 + v0 * m13);
        float t30 = - (v3 * m10 - v1 * m11 + v0 * m12);

        float invDet = 1 / (t00 * m00 + t10 * m01 + t20 * m02 + t30 * m03);

        float d00 = t00 * invDet;
        float d10 = t10 * invDet;
        float d20 = t20 * invDet;
        float d30 = t30 * invDet;

        float d01 = - (v5 * m01 - v4 * m02 + v3 * m03) * invDet;
        float d11 = + (v5 * m00 - v2 * m02 + v1 * m03) * invDet;
        float d21 = - (v4 * m00 - v2 * m01 + v0 * m03) * invDet;
        float d31 = + (v3 * m00 - v1 * m01 + v0 * m02) * invDet;

        v0 = m10 * m31 - m11 * m30;
        v1 = m10 * m32 - m12 * m30;
        v2 = m10 * m33 - m13 * m30;
        v3 = m11 * m32 - m12 * m31;
        v4 = m11 * m33 - m13 * m31;
        v5 = m12 * m33 - m13 * m32;

        float d02 = + (v5 * m01 - v4 * m02 + v3 * m03) * invDet;
        float d12 = - (v5 * m00 - v2 * m02 + v1 * m03) * invDet;
        float d22 = + (v4 * m00 - v2 * m01 + v0 * m03) * invDet;
        float d32 = - (v3 * m00 - v1 * m01 + v0 * m02) * invDet;

        v0 = m21 * m10 - m20 * m11;
        v1 = m22 * m10 - m20 * m12;
        v2 = m23 * m10 - m20 * m13;
        v3 = m22 * m11 - m21 * m12;
        v4 = m23 * m11 - m21 * m13;
        v5 = m23 * m12 - m22 * m13;

        float d03 = - (v5 * m01 - v4 * m02 + v3 * m03) * invDet;
        float d13 = + (v5 * m00 - v2 * m02 + v1 * m03) * invDet;
        float d23 = - (v4 * m00 - v2 * m01 + v0 * m03) * invDet;
        float d33 = + (v3 * m00 - v1 * m01 + v0 * m02) * invDet;

        return Matrix4(
            d00, d01, d02, d03,
            d10, d11, d12, d13,
            d20, d21, d22, d23,
            d30, d31, d32, d33);
    }

    Matrix4 Matrix4::inverseAffine() const
    {
        assert(isAffine());

        float m10 = m[1][0], m11 = m[1][1], m12 = m[1][2];
        float m20 = m[2][0], m21 = m[2][1], m22 = m[2][2];

        float t00 = m22 * m11 - m21 * m12;
        float t10 = m20 * m12 - m22 * m10;
        float t20 = m21 * m10 - m20 * m11;

        float m00 = m[0][0], m01 = m[0][1], m02 = m[0][2];

        float invDet = 1 / (m00 * t00 + m01 * t10 + m02 * t20);

        t00 *= invDet; t10 *= invDet; t20 *= invDet;

        m00 *= invDet; m01 *= invDet; m02 *= invDet;

        float r00 = t00;
        float r01 = m02 * m21 - m01 * m22;
        float r02 = m01 * m12 - m02 * m11;

        float r10 = t10;
        float r11 = m00 * m22 - m02 * m20;
        float r12 = m02 * m10 - m00 * m12;

        float r20 = t20;
        float r21 = m01 * m20 - m00 * m21;
        float r22 = m00 * m11 - m01 * m10;

        float m03 = m[0][3], m13 = m[1][3], m23 = m[2][3];

        float r03 = - (r00 * m03 + r01 * m13 + r02 * m23);
        float r13 = - (r10 * m03 + r11 * m13 + r12 * m23);
        float r23 = - (r20 * m03 + r21 * m13 + r22 * m23);

        return Matrix4(
            r00, r01, r02, r03,
            r10, r11, r12, r13,
            r20, r21, r22, r23,
              0,   0,   0,   1);
    }

    void Matrix4::setTRS(const Vector3& translation, const Quaternion& rotation, const Vector3& scale)
    {
        Matrix3 rot3x3;
        rotation.toRotationMatrix(rot3x3);

        m[0][0] = scale.x * rot3x3[0][0]; m[0][1] = scale.y * rot3x3[0][1]; m[0][2] = scale.z * rot3x3[0][2]; m[0][3] = translation.x;
        m[1][0] = scale.x * rot3x3[1][0]; m[1][1] = scale.y * rot3x3[1][1]; m[1][2] = scale.z * rot3x3[1][2]; m[1][3] = translation.y;
        m[2][0] = scale.x * rot3x3[2][0]; m[2][1] = scale.y * rot3x3[2][1]; m[2][2] = scale.z * rot3x3[2][2]; m[2][3] = translation.z;

        // No projection term
        m[3][0] = 0; m[3][1] = 0; m[3][2] = 0; m[3][3] = 1;
    }

    void Matrix4::setInverseTRS(const Vector3& translation, const Quaternion& rotation, const Vector3& scale)
    {
        // Invert the parameters
        Vector3 invTranslate = -translation;
        Vector3 invScale(1 / scale.x, 1 / scale.y, 1 / scale.z);
        Quaternion invRot = rotation.inverse();

        // Because we're inverting, order is translation, rotation, scale
        // So make translation relative to scale & rotation
        invTranslate = invRot.rotate(invTranslate);
        invTranslate *= invScale;

        // Next, make a 3x3 rotation matrix
        Matrix3 rot3x3;
        invRot.toRotationMatrix(rot3x3);

        // Set up final matrix with scale, rotation and translation
        m[0][0] = invScale.x * rot3x3[0][0]; m[0][1] = invScale.x * rot3x3[0][1]; m[0][2] = invScale.x * rot3x3[0][2]; m[0][3] = invTranslate.x;
        m[1][0] = invScale.y * rot3x3[1][0]; m[1][1] = invScale.y * rot3x3[1][1]; m[1][2] = invScale.y * rot3x3[1][2]; m[1][3] = invTranslate.y;
        m[2][0] = invScale.z * rot3x3[2][0]; m[2][1] = invScale.z * rot3x3[2][1]; m[2][2] = invScale.z * rot3x3[2][2]; m[2][3] = invTranslate.z;		

        // No projection term
        m[3][0] = 0; m[3][1] = 0; m[3][2] = 0; m[3][3] = 1;
    }

	void Matrix4::decomposition(Vector3& position, Quaternion& rotation, Vector3& scale) const
	{
		Matrix3 m3x3;
		extract3x3Matrix(m3x3);

		Matrix3 matQ;
		Vector3 vecU;
		m3x3.QDUDecomposition(matQ, scale, vecU); 

		rotation = Quaternion(matQ);
		position = Vector3(m[0][3], m[1][3], m[2][3]);
	}

	void Matrix4::makeView(const Vector3& position, const Quaternion& orientation, const Matrix4* reflectMatrix)
	{
		// View matrix is:
		//
		//  [ Lx  Uy  Dz  Tx  ]
		//  [ Lx  Uy  Dz  Ty  ]
		//  [ Lx  Uy  Dz  Tz  ]
		//  [ 0   0   0   1   ]
		//
		// Where T = -(Transposed(Rot) * Pos)

		// This is most efficiently done using 3x3 Matrices
		Matrix3 rot;
		orientation.toRotationMatrix(rot);

		// Make the translation relative to new axes
		Matrix3 rotT = rot.transpose();
		Vector3 trans = (-rotT).transform(position);

		// Make final matrix
		*this = Matrix4(rotT);
		m[0][3] = trans.x;
		m[1][3] = trans.y;
		m[2][3] = trans.z;

		// Deal with reflections
		if (reflectMatrix)
		{
			*this = (*this) * (*reflectMatrix);
		}
	}
}