public void Matrix3x2CreateSkewIdentityTest()
{
Matrix3x2 expected = Matrix3x2.Identity;
Matrix3x2 actual = Matrix3x2.CreateSkew(0, 0);
Assert.Equal(expected, actual);
}
public void Matrix3x2CreateSkewCenterTest()
{
Single skewX = 1, skewY = 2;
Vector2 center = new Vector2(23, 42);
Matrix3x2 skewAroundZero = Matrix3x2.CreateSkew(skewX, skewY, Vector2.Zero);
Matrix3x2 skewAroundZeroExpected = Matrix3x2.CreateSkew(skewX, skewY);
Assert.True(MathHelper.Equal(skewAroundZero, skewAroundZeroExpected));
Matrix3x2 skewAroundCenter = Matrix3x2.CreateSkew(skewX, skewY, center);
Matrix3x2 skewAroundCenterExpected = Matrix3x2.CreateTranslation(-center) * Matrix3x2.CreateSkew(skewX, skewY) * Matrix3x2.CreateTranslation(center);
Assert.True(MathHelper.Equal(skewAroundCenter, skewAroundCenterExpected));
}
public void Matrix3x2CreateSkewXYTest()
{
Matrix3x2 expected = new Matrix3x2(1, -0.414213562373095f, 1, 1, 0, 0);
Matrix3x2 actual = Matrix3x2.CreateSkew(MathHelper.Pi / 4, -MathHelper.Pi / 8);
Assert.True(MathHelper.Equal(expected, actual));
Vector2 result = Vector2.Transform(new Vector2(0, 0), actual);
Assert.True(MathHelper.Equal(new Vector2(0, 0), result));
result = Vector2.Transform(new Vector2(1, 0), actual);
Assert.True(MathHelper.Equal(new Vector2(1, -0.414213562373095f), result));
result = Vector2.Transform(new Vector2(0, 1), actual);
Assert.True(MathHelper.Equal(new Vector2(1, 1), result));
result = Vector2.Transform(new Vector2(1, 1), actual);
Assert.True(MathHelper.Equal(new Vector2(2, 0.585786437626905f), result));
}
public void Matrix3x2CreateSkewYTest()
{
Matrix3x2 expected = new Matrix3x2(1, -0.414213562373095f, 0, 1, 0, 0);
Matrix3x2 actual = Matrix3x2.CreateSkew(0, -MathHelper.Pi / 8);
Assert.True(MathHelper.Equal(expected, actual));
expected = new Matrix3x2(1, 0.414213562373095f, 0, 1, 0, 0);
actual = Matrix3x2.CreateSkew(0, MathHelper.Pi / 8);
Assert.True(MathHelper.Equal(expected, actual));
Vector2 result = Vector2.Transform(new Vector2(0, 0), actual);
Assert.True(MathHelper.Equal(new Vector2(0, 0), result));
result = Vector2.Transform(new Vector2(1, 0), actual);
Assert.True(MathHelper.Equal(new Vector2(1, 0.414213568f), result));
result = Vector2.Transform(new Vector2(-1, 0), actual);
Assert.True(MathHelper.Equal(new Vector2(-1, -0.414213568f), result));
result = Vector2.Transform(new Vector2(10, 3), actual);
Assert.True(MathHelper.Equal(new Vector2(10, 7.14213568f), result));
}