src/math/mat2d.cpp

#include "rive/math/mat2d.hpp"
#include "rive/math/transform_components.hpp"
#include "rive/math/vec2d.hpp"
#include <cmath>

using namespace rive;

Mat2D::Mat2D() : m_Buffer{1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f} {}

Mat2D::Mat2D(const Mat2D& copy) :
    m_Buffer{copy[0], copy[1], copy[2], copy[3], copy[4], copy[5]}
{
}

Mat2D::Mat2D(float x1, float y1, float x2, float y2, float tx, float ty) :
    m_Buffer{x1, y1, x2, y2, tx, ty}
{
}

void Mat2D::fromRotation(Mat2D& result, float rad)
{
	float s = sin(rad);
	float c = cos(rad);
	result[0] = c;
	result[1] = s;
	result[2] = -s;
	result[3] = c;
	result[4] = 0;
	result[5] = 0;
}

void Mat2D::scale(Mat2D& result, const Mat2D& mat, const Vec2D& vec)
{
	float v0 = vec[0], v1 = vec[1];
	result[0] = mat[0] * v0;
	result[1] = mat[1] * v0;
	result[2] = mat[2] * v1;
	result[3] = mat[3] * v1;
	result[4] = mat[4];
	result[5] = mat[5];
}

void Mat2D::multiply(Mat2D& result, const Mat2D& a, const Mat2D& b)
{
	float a0 = a[0], a1 = a[1], a2 = a[2], a3 = a[3], a4 = a[4], a5 = a[5],
	      b0 = b[0], b1 = b[1], b2 = b[2], b3 = b[3], b4 = b[4], b5 = b[5];
	result[0] = a0 * b0 + a2 * b1;
	result[1] = a1 * b0 + a3 * b1;
	result[2] = a0 * b2 + a2 * b3;
	result[3] = a1 * b2 + a3 * b3;
	result[4] = a0 * b4 + a2 * b5 + a4;
	result[5] = a1 * b4 + a3 * b5 + a5;
}

bool Mat2D::invert(Mat2D& result, const Mat2D& a)
{
	float aa = a[0], ab = a[1], ac = a[2], ad = a[3], atx = a[4], aty = a[5];

	float det = aa * ad - ab * ac;
	if (det == 0.0f)
	{
		return false;
	}
	det = 1.0f / det;

	result[0] = ad * det;
	result[1] = -ab * det;
	result[2] = -ac * det;
	result[3] = aa * det;
	result[4] = (ac * aty - ad * atx) * det;
	result[5] = (ab * atx - aa * aty) * det;
	return true;
}

void Mat2D::copy(Mat2D& result, const Mat2D& a)
{
	result[0] = a[0];
	result[1] = a[1];
	result[2] = a[2];
	result[3] = a[3];
	result[4] = a[4];
	result[5] = a[5];
}

void Mat2D::decompose(TransformComponents& result, const Mat2D& m)
{
	float m0 = m[0], m1 = m[1], m2 = m[2], m3 = m[3];

	float rotation = (float)std::atan2(m1, m0);
	float denom = m0 * m0 + m1 * m1;
	float scaleX = (float)std::sqrt(denom);
	float scaleY = (m0 * m3 - m2 * m1) / scaleX;
	float skewX = (float)std::atan2(m0 * m2 + m1 * m3, denom);

	result.x(m[4]);
	result.y(m[5]);
	result.scaleX(scaleX);
	result.scaleY(scaleY);
	result.rotation(rotation);
	result.skew(skewX);
}

void Mat2D::compose(Mat2D& result, const TransformComponents& components)
{
	float r = components.rotation();

	if (r != 0.0f)
	{
		Mat2D::fromRotation(result, r);
	}
	else
	{
		Mat2D::identity(result);
	}
	result[4] = components.x();
	result[5] = components.y();
	Vec2D scale;
	components.scale(scale);
	Mat2D::scale(result, result, scale);

	float sk = components.skew();
	if (sk != 0.0f)
	{
		result[2] = result[0] * sk + result[2];
		result[3] = result[1] * sk + result[3];
	}
}

void Mat2D::scaleByValues(Mat2D& result, float sx, float sy)
{
	result[0] *= sx;
	result[1] *= sx;
	result[2] *= sy;
	result[3] *= sy;
}