DistributionFunctions.cs

// Uniform random distribution.
// Great for effects with a limited number of samples, like SSAO.
public static Vector4[] UniformKernel(int n, bool hemisphere)
{
	Random.State state = Random.state;
	// Set the random seed so repeat calls with n samples always returns the same result
	Random.InitState(0);

	Vector4[] result = new Vector4[n];
	for (int i = 0; i < n; i++)
	{
		result[i] = new Vector3(Random.value * 2 - 1, hemisphere ? Random.value : Random.value * 2 - 1, Random.value * 2 - 1).normalized;

		// Scale vector length with sample index. This is great for SSAO implementations. Scalar length is stored in .w
		float d = (i + 0.5f) / n;
		result[i].w = 1;
		result[i] *= Mathf.Lerp(0.1f, 1.0f, d * d);
	}

	Random.state = state;

	return result;
}

// Fibonacci or "sunflower" distribution.
// Great for getting an even result when baking things, like ambient occlusion.
public static Vector4[] SunflowerKernel(int n, bool hemisphere)
{
	Vector4[] result = new Vector4[n];
	float phi = Mathf.PI * (3f - Mathf.Sqrt(5f)); // Golden angle in radians

	for (int i = 0; i < n; i++)
	{
		float y = 1 - ((float)i / (n - 1)) * 2; // Y goes from 1 to -1
		float radius = Mathf.Sqrt(1 - y * y); // Radius at y

		float theta = phi * i; // Golden angle increment

		float x = Mathf.Cos(theta) * radius;
		float z = Mathf.Sin(theta) * radius;
		result[i] = new Vector3(x, hemisphere ? Mathf.Abs(y) : y, z);
	}

	return result;
}