public override Vec3 GetColor(BaseLight light, Ray view_ray, HitRecord record, float depth)
{
//Phong公式: L = Kd * I * max(0, n·l) + Ks * I * max(0, n·h)^p
// Kd是散射系数, n是表面法向量,l是光源方向(从相交点指向光源), Ks是高光系数,h是v+l的单位向量,v是视线反方向(从相交点只想视点), I是光强(光在这一点的颜色)
Vec3 l = -(light.GetLightRay(record.hit_point, view_ray.DeltaTime).Direction.normalize());
float n_dot_l = Math.Max(0, Vec3.dot(record.normal, l));
Vec3 h = (-view_ray.Direction + l).normalize();
float n_dot_h = Math.Max(0, Vec3.dot(record.normal, h));
Vec3 I = Vec3.one;
Vec3 dif = diffuse * n_dot_l;
Vec3 spe = specular * (float)Math.Pow(n_dot_h, phong_exp);
spe *= _smoothstep(0, 0.12f, n_dot_l);//为了解决背光面高光的问题,如果n_dot_l<0直接spe=0会有颜色间断层,需要做插值处理
Vec3 L = Vec3.product(I, dif + spe);
//上面有两个bug/疑问
//(1)背光面也能出现高光,因为公式里n·l<0并不影响 Ks * I * max(0, n·h)^p的值;
//(2)求出来的L超过(1,1,1)范围了.---暂时强行映射到[0,1]
//上面两个问题估计都是要改diffuse和specular来处理
//目前先特殊处理下,以后看看大佬们怎么搞的
return(L);
}
public override Vec3 GetColor(BaseLight light, Ray view_ray, HitRecord record, float depth)
{
//把光在某一点的颜色，用距离映射到颜色区间
//[0, depth] -- > [0, 255]不过,len = 0的时候是255, len = depth的时候是0
float coeffience = 1 - (record.t / depth);
return(texture.GetColorValue(0, 0, null) * coeffience);
}
public override Vec3 GetColor(BaseLight light, Ray view_ray, HitRecord record, float depth)
{
Vec3 l = -(light.GetLightRay(record.hit_point, view_ray.DeltaTime).Direction.normalize());
float n_dot_l = Math.Max(0, Vec3.dot(record.normal, l));
Vec3 I = Vec3.one;
Vec3 dif = diffuse * n_dot_l;
Vec3 L = Vec3.product(I, dif);
return(L);
}
public override Vec3 GetColor(BaseLight light, Ray view_ray, HitRecord record, float depth)
{
Vec3 l = -(light.GetLightRay(record.hit_point, view_ray.DeltaTime).Direction.normalize());
float n_dot_l = Math.Max(0, Vec3.dot(record.normal, l));
Vec3 I = Vec3.one;
Vec3 color = texture == null ? diffuse : texture.GetColorValue(0, 0, record.hit_point);//这里还要改的，下面的material也是，感觉material用来定义反射之类的物理计算公式。颜色映射还是交给texture吧
Vec3 dif = color * n_dot_l;
Vec3 L = Vec3.product(I, dif);
return(L);
}
/// <summary>
///
/// </summary>
/// <param name="light">光源</param>
/// <param name="view_ray">视线</param>
/// <param name="record">相交信息</param>
/// <param name="depth">渲染深度</param>
/// <returns></returns>
public virtual Vec3 GetColor(BaseLight light, Ray view_ray, HitRecord record, float depth)
{
throw new NotImplementedException();
}
