public void CenterNormalIsStraightUpWhenRoughnessIsZero()
{
var v = new Vector(1, 1, 1).Normalize();
var n = GGXNormalDistribution.GGXVndf(v, 0f, 0f, 0, 0);
n.Should().Be(new Vector(0, 0, 1));
v = new Vector(1, 2, 3).Normalize();
n = GGXNormalDistribution.GGXVndf(v, 0f, 0f, 0, 0);
n.Should().Be(new Vector(0, 0, 1));
}
public void ShouldHaveLowOffsetWhenNearZero()
{
var v = new Vector(0, 1, 1).Normalize();
var n = GGXNormalDistribution.GGXVndf(v, 0.001f, 0.001f, 0f, 0f);
n.Should().Be(new Vector(0, 0, 1));
v = new Vector(1, 2, 1).Normalize();
n = GGXNormalDistribution.GGXVndf(v, 0.001f, 0.001f, 0f, 0f);
n.Should().Be(new Vector(0, 0, 1));
}
public void RotatesNormalProportionalToAlphaXY()
{
var v = new Vector(1, 1, 1).Normalize();
var n = GGXNormalDistribution.GGXVndf(v, 0f, 0f, 0, 0);
n.Should().Be(new Vector(0, 0, 1));
v = new Vector(1, 1, 1).Normalize();
n = GGXNormalDistribution.GGXVndf(v, 1f, 0f, 0, 0);
n.X.Should().BeGreaterThan(0f);
n.Y.Should().Be(0f);
v = new Vector(1, 1, 1).Normalize();
n = GGXNormalDistribution.GGXVndf(v, 0f, 1f, 0, 0);
n.Y.Should().BeGreaterThan(0f);
n.X.Should().Be(0f);
}