public static Texture2D GetSphericalTexture2D(this Cubemap cubemap)
{
int w = cubemap.width * 2;
int h = cubemap.height * 2;
Texture2D texture2D = new Texture2D(w, h, cubemap.format, false);
Color backColor = cubemap.GetColorInDirection(-Vector3.forward);
for (int j = 0; j < h; j++)
{
for (int i = 0; i < w; i++)
{
float x = (float)i / (float)w;
float y = (float)j / (float)h;
float d = Vector2.Distance(Vector2.one * 0.5f, new Vector2(x, y));
if (d <= 0.5f)
{
float r = 2 * Mathf.Sqrt(-4 * x * x + 4 * x - 1 - 4 * y * y + 4 * y);
Vector3 dir = new Vector3(
r * (2 * x - 1),
r * (2 * y - 1),
-8 * x * x + 8 * x - 8 * y * y + 8 * y - 3
);
texture2D.SetPixel(i, j, cubemap.GetColorInDirection(dir));
}
else
{
texture2D.SetPixel(i, j, backColor);
}
}
}
texture2D.Apply();
return(texture2D);
}
public static Texture2D GetCylindricalTexture2D(this Cubemap cubemap)
{
int w = cubemap.width * 4;
int h = cubemap.height * 2;
Texture2D texture2D = new Texture2D(w, h, cubemap.format, false);
for (int j = 0; j < h; j++)
{
for (int i = 0; i < w; i++)
{
float a = (((float)i / (float)w) - 0.25f) * Mathf.PI * 2;
float x = -Mathf.Cos(a);
float y = Mathf.Sin(a);
Vector3 dir = new Vector3(x, 0, y);
float b = ((float)j / (float)h);
if (b > 0.5f)
{
dir = Vector3.Slerp(dir, Vector3.up, (b - 0.5f) * 2);
}
else
{
dir = Vector3.Slerp(dir, -Vector3.up, 1 - b * 2);
}
texture2D.SetPixel(i, j, cubemap.GetColorInDirection(dir));
}
}
texture2D.Apply();
return(texture2D);
}
