/// <summary>
/// 利用层次包围盒计算颜色
/// </summary>
/// <param name="r"></param>
/// <param name="world"></param>
/// <param name="depth"></param>
/// <returns></returns>
public static SColor Color(Ray r, BVH_node world, int depth)
{
AABB aBB = new AABB();
world.Bounding_box(0, 0, ref aBB);
if (aBB.Hit(r, 1e-5))
{
ShadeRec rec = new ShadeRec();
world.Hit(r, 1e-5, ref rec);
if (rec.IsHit)
{
Ray scattered = new Ray();
Vector3D attenuation = new Vector3D();
SColor emitted = rec.Material.Emitted(rec);//光颜色
if (depth < 1 && rec.Material.Scatter(r, rec, ref attenuation, ref scattered))
{
SColor colorTemp = Color(scattered, world, depth + 1);
colorTemp = colorTemp * new SColor(attenuation);
//有反射则将当前发光体发出的光和散射的颜色预以叠加
return(colorTemp + emitted);
}
else
{
//无反射则直接取发光射出的颜色
return(emitted);
}
}
else
{
Vector3D unitDirection = Vector3D.UnitVector(r.Direction);
double t = 0.5 * (unitDirection.Y + 1.0);
return(new SColor((1.0 - t) + t * 0.5, (1.0 - t) + t * 0.7, (1.0 - t) + t * 1));
// return new SColor(1, 1, 1);//无背景色
}
}
else
{
Vector3D unitDirection = Vector3D.UnitVector(r.Direction);
double t = 0.5 * (unitDirection.Y + 1.0);
return(new SColor((1.0 - t) + t * 0.5, (1.0 - t) + t * 0.7, (1.0 - t) + t * 1));
// return new SColor(1, 0, 0);//无背景色
}
}
/// <summary>
/// 传入射线是否击中物体
/// </summary>
/// <param name="r">射线</param>
/// <param name="t_min">t可以取的最小值</param>
/// <param name="rec">击中点信息</param>
/// <returns>是否击中</returns>
public virtual bool Hit(Ray r, double t_min, ref ShadeRec rec)
{
return(false);
}
public abstract Vector3 Shade(ShadeRec sr);
public virtual Vector3 ShadeAreaLight(ShadeRec sr)
{
return(Shade(sr));
}
public abstract SColor GetColor(ShadeRec sr);