public Color4 Render()
{
if (first)
{
float inertT = Scene.scene.Intersect(this, ref interTG, ref normal, ref interColor);
interPos = origin + dir * inertT; // 交点坐标
first = false;
}
if (interTG == null)
{
return(Scene.AmbientColor);
}
Material mat = interTG.Material;
if (mat.Surface == Surface.EMISSION)
{
return(interColor);
}
if (reflectNum > 0)
{
if (mat.Surface == Surface.DIFFUSE) // 漫反射
//if (interColor.ReflectRatio < 0.1f) {
// return interColor;
//}
{
if (Vector3.rand.NextDouble() < interColor.ReflectRatio * 3) // 反射率小的时候就降低渲染概率，比如纯黑的墙壁
{
Ray diffRay = new Ray(interPos, Vector3.RandInUnitHemisphere(normal), reflectNum - 1); // 每次都不一样，局部变量
Color4 color4 = diffRay.Render();
if (color4.L > 0f)
{
reflColorSum += color4;
reflColorNum++;
reflColor = reflColorSum / reflColorNum;
color = Color4.Mix(interColor, reflColor);
}
}
}
else if (mat.Surface == Surface.SPECULAR) // 镜面反射
{
if (reflRay == null)
{
reflRay = new Ray(interPos, Vector3.Reflect(dir, normal), reflectNum - 1);
}
reflColor = reflRay.Render();
if (mat.RefrRatio > 0f) // 折射
{
if (refrRay == null && fresnel != 1f)
{
if (Vector3.Refract(dir, normal, mat.RefrRatio, out Vector3 refrect))
{
refrRay = new Ray(interPos, refrect, reflectNum - 1);
fresnel = 1f - Mathf.Abs(dir * normal);
}
else
{
fresnel = 1f; // 全反射
}
}
if (refrRay != null)
{
refrColor = refrRay.Render();
color = Color4.Mix(interColor, reflColor * fresnel + refrColor * (1 - fresnel));
}
else
{
color = Color4.Mix(interColor, reflColor);
}
}
else
{
color = Color4.Mix(interColor, reflColor);
}
}
}
else
{
return(interColor);
}
return(color);
}
