// A standard square grid 2D blobby Truchet routine: Render circles
// in opposite corners of a tile, reverse the pattern on alternate
// checker tiles, and randomly rotate.
private static float Truchet(Float2 p)
{
const float sc = 0.5f;
Float2 ip = Hlsl.Floor(p / sc) + 0.5f;
p -= ip * sc;
float rnd = Hlsl.Frac(Hlsl.Sin(Hlsl.Dot(ip, new Float2(1, 113))) * 45758.5453f);
if (rnd < .5)
{
p.Y = -p.Y;
}
float d = Hlsl.Min(Distance(p - 0.5f * sc), Distance(p + 0.5f * sc)) - 0.5f * sc;
if (SHAPE == 4)
{
d += (0.5f - 0.5f / Hlsl.Sqrt(2.0f)) * sc;
}
if (rnd < 0.5f)
{
d = -d;
}
if (Mod(ip.X + ip.Y, 2.0f) < 0.5f)
{
d = -d;
}
return(d - 0.03f);
}
/// <inheritdoc/>
public float4 Execute()
{
float2 position = ((float2)(256 * ThreadIds.XY)) / DispatchSize.X + time;
float4 color = 0;
for (int i = 0; i < 6; i++)
{
float2 a = Hlsl.Floor(position);
float2 b = Hlsl.Frac(position);
float4 w = Hlsl.Frac(
(Hlsl.Sin(a.X * 7 + 31.0f * a.Y + 0.01f * time) +
new float4(0.035f, 0.01f, 0, 0.7f))
* 13.545317f);
color.XYZ += w.XYZ *
2.0f * Hlsl.SmoothStep(0.45f, 0.55f, w.W) *
Hlsl.Sqrt(16.0f * b.X * b.Y * (1.0f - b.X) * (1.0f - b.Y));
position /= 2.0f;
color /= 2.0f;
}
color.XYZ = Hlsl.Pow(color.XYZ, new float3(0.7f, 0.8f, 0.5f));
color.W = 1.0f;
return(color);
}
// float2 to float2 hash.
private float2 Hash22(float2 p)
{
float n = Hlsl.Sin(Hlsl.Dot(p, new float2(1, 113)));
p = Hlsl.Frac(new float2(262144, 32768) * n);
return(Hlsl.Sin(p * 6.2831853f + time));
}
/// <inheritdoc/>
public float4 Execute()
{
float2 uv = (ThreadIds.XY - (float2)DispatchSize.XY * 0.5f) / DispatchSize.Y;
float3 col = 0;
float t = time * 0.3f;
for (float i = 0.0f; i <= 1.0f; i += 1.0f / NumberOfLayers)
{
float d = Hlsl.Frac(i + t);
float s = Hlsl.Lerp(5.0f, 0.5f, d);
float f = d * Hlsl.SmoothStep(1.0f, 0.9f, d);
col += Tex(new float3(uv.X * s, uv.Y * s, i * 4.0f)).XYZ *f;
}
col /= NumberOfLayers;
col *= new float3(2, 1.0f, 2.0f);
col = Hlsl.Pow(col, 0.5f);
return(new(col.X, col.Y, col.Z, 1.0f));
}
// Fast hash for a pair of floats
static float Hash21(float2 p)
{
return(Hlsl.Frac(Hlsl.Sin(Hlsl.Dot(p, new float2(27.619f, 57.583f))) * 43758.5453f));
}
// float2 to float2 hash.
private static float2 Hash22B(float2 p)
{
float n = Hlsl.Sin(Hlsl.Dot(p, new float2(41, 289)));
return(Hlsl.Frac(new float2(262144, 32768) * n) * 2.0f - 1.0f);
}
// float3 to float hash.
private static float Hash21(float2 p)
{
return(Hlsl.Frac(Hlsl.Sin(Hlsl.Dot(p, new float2(41, 289))) * 45758.5453f));
}