public UnityEngine.Vector2 GetScale(GBA_Animation anim, GBA_SpriteGroup spriteGroup, int frameIndex)
{
if (TransformMode == AffineObjectMode.Affine || TransformMode == AffineObjectMode.AffineDouble)
{
if (spriteGroup.Matrices.ContainsKey(anim.AffineMatricesIndex))
{
var m = spriteGroup.Matrices[anim.AffineMatricesIndex].GetMatrix(AffineMatrixIndex, frameIndex);
if (m != null)
{
var a = m.Pa / 256f;
var b = m.Pb / 256f;
var c = m.Pc / 256f;
var d = m.Pd / 256f;
var delta = a * d - b * c;
//var rotation = 0f;
var scale = UnityEngine.Vector2.zero;
//var skew = UnityEngine.Vector2.zero;
// Apply the QR-like decomposition.
if (a != 0 || b != 0)
{
var r = Mathf.Sqrt(a * a + b * b);
//rotation = b > 0 ? Mathf.Acos(a / r) : -Mathf.Acos(a / r);
scale = new UnityEngine.Vector2(r, delta / r);
//skew = new UnityEngine.Vector2(Mathf.Atan((a * c + b * d) / (r * r)), 0);
}
else if (c != 0 || d != 0)
{
var s = Mathf.Sqrt(c * c + d * d);
//rotation =
// Mathf.PI / 2 - (d > 0 ? Mathf.Acos(-c / s) : -Mathf.Acos(c / s));
scale = new UnityEngine.Vector2(delta / s, s);
//skew = new UnityEngine.Vector2(0, Mathf.Atan((a * c + b * d) / (s * s)));
}
else
{
// a = b = c = d = 0
}
if (scale.x != 0)
{
scale.x = 1f / scale.x;
}
if (scale.y != 0)
{
scale.y = 1f / scale.y;
}
return(scale);
// Resources:
// https://wiki.nycresistor.com/wiki/GB101:Affine_Sprites
// https://www.coranac.com/tonc/text/affine.htm
// https://www.coranac.com/tonc/text/affobj.htm
}
}
}
return(UnityEngine.Vector2.one);
}
public float GetRotation(GBA_Animation anim, GBA_SpriteGroup spriteGroup, int frameIndex)
{
if (TransformMode == AffineObjectMode.Affine || TransformMode == AffineObjectMode.AffineDouble)
{
if (spriteGroup.Matrices.ContainsKey(anim.AffineMatricesIndex))
{
var m = spriteGroup.Matrices[anim.AffineMatricesIndex].GetMatrix(AffineMatrixIndex, frameIndex);
if (m != null)
{
var rotation = -Mathf.Atan2(m.Pb / 256f, m.Pa / 256f);
return(rotation * Mathf.Rad2Deg);
// Resources:
// https://stackoverflow.com/questions/45159314/decompose-2d-transformation-matrix
// https://wiki.nycresistor.com/wiki/GB101:Affine_Sprites
// https://www.coranac.com/tonc/text/affine.htm
// https://www.coranac.com/tonc/text/affobj.htm
}
}
}
return(0f);
}
