private void ReflectFunc(Ray ray, RaycastHit hit, MicrofacetModel BRDF, int depth, float multi, ref Color slightColor, ref Color dlightColor)
{
//反射
var V = -ray.direction;
var N = hit.normal;
var dirs = BRDF.ReflectDirections(N, V, reflectCount);
float countInv = 1.0f / dirs.Count;
foreach (var reflectDir in dirs)
{
var L = reflectDir;
Ray refRay = new Ray(hit.point + N * 0.001f, reflectDir);
//if (FixNLV(ref N, L, V) == false) continue;
var s = BRDF.getSIntensity(N, L, V);
var d = BRDF.getDIntensity();
Color reflectColor = Color.black;
RaycastHit reflecthit;
if (RayTracing(refRay, out reflectColor, out reflecthit, depth + 1, multi * Math.Max(s, d)))
{
float intensity = countInv;
reflectColor *= intensity;
//高光计算
slightColor += reflectColor * s;
//漫反射计算
dlightColor += reflectColor * d;
}
}
}
private void Lighting(Ray ray, RaycastHit hit, MicrofacetModel BRDF, ref Color slightColor, ref Color dlightColor)
{
foreach (var light in lights)
{
switch (light.type)
{
case LightType.Spot:
{
}
break;
case LightType.Directional:
break;
case LightType.Point:
{
var L = light.transform.position - hit.point;
var len = L.magnitude;
L.Normalize();
//点到光源之间被遮挡，阴影特效
if (len > light.range || Physics.Raycast(hit.point + hit.normal * 0.001f, L, len))
{
break;
}
var N = hit.normal;
var V = -ray.direction;
//在碰撞点上面的光强
var intensity = light.intensity;
intensity *= (float)(Math.Pow(1 - len / light.range, 2)); //光根据距离衰减
intensity *= Math.Max(0, Vector3.Dot(N, L)); //光投影到面的衰减
//if (FixNLV(ref N, L, V) == false) continue;
//高光计算
slightColor += light.color * intensity * BRDF.getSIntensity(N, L, V);
//漫反射计算
dlightColor += light.color * intensity * BRDF.getDIntensity(); //在半球上进行均匀漫反射 d*1/(2*pi)
}
break;
case LightType.Area:
break;
default:
break;
}
}
}
bool RayTracing(Ray ray, out Color desColor, out RaycastHit hit, int depth = 0, float multi = 1)
{
desColor = Color.black;
hit = new RaycastHit();
if (depth >= maxDepth)
{
return(false);
}
if (multi < 0.001)
{
return(false);
}
if (Physics.Raycast(ray, out hit))
{
//是否在物体内部发生碰撞
bool isOutside = Vector3.Dot(hit.normal, -ray.direction) > 0;
//双向反射分布模型
var BRDF = new MicrofacetModel();
//表面颜色
Color textureColor = Color.white;
var meshRenderer = hit.transform.GetComponent <MeshRenderer>();
int mode = 0;
if (meshRenderer && meshRenderer.material)
{
var material = meshRenderer.material;
textureColor = material.color;
var texture = material.mainTexture as Texture2D;
if (texture)
{
textureColor *= texture.GetPixelBilinear(hit.textureCoord.x, hit.textureCoord.y);
}
//0不透明，3透明
mode = material.GetInt("_Mode");
float Metallic = material.GetFloat("_Metallic"); //金属
float Smoothness = material.GetFloat("_Glossiness"); //高光分布
BRDF.S = Metallic;
BRDF.m = 1 - Smoothness;
}
Color slightColor = Color.black;
Color dlightColor = Color.black;
Color refractColor = Color.black;
Lighting(ray, hit, BRDF, ref slightColor, ref dlightColor);
//递归追踪,看似光源的一种
bool isRefract = false;
if (isReflect)
{
if (mode == 3 && refractiveIndices > 0.01f)
{
Vector3 refractV;
float ni_over_nt = refractiveIndices;
var N = hit.normal;
var V = -ray.direction;
if (isOutside)
{
ni_over_nt = 1 / ni_over_nt;
}
else
{
N = -N;
}
if (Refract(V, N, ni_over_nt, out refractV))
{
var F = (float)BRDF.Fresnel_Reflection(N, V);
RaycastHit refractInfo;
var m = multi * (1f - F);
var rayRefract = new Ray(hit.point + refractV * 0.0001f, refractV);
RayTracing(rayRefract, out refractColor, out refractInfo, depth + 1, m);
isRefract = true;
refractColor *= 1 - F;
}
}
if (!isOutside)
{
hit.normal = -hit.normal;
}
ReflectFunc(ray, hit, BRDF, depth, multi, ref slightColor, ref dlightColor);
}
var faceColor = textureColor;
desColor = faceColor * dlightColor + slightColor;
if (isRefract)
{
desColor += faceColor * refractColor;//漫反射
}
//按照距离衰减
if (depth != 0)
{
float intensity = 1;
float len = (hit.point - ray.origin).magnitude;
if (len >= 100)
{
intensity = 0;
}
intensity *= (float)(Math.Pow(1 - len / 100, 2));//光根据距离衰减
//intensity *= Math.Max(0, Vector3.Dot(hit.normal, -ray.direction));//光投影到面的衰减
desColor *= intensity;
}
desColor.a = 1;
return(true);
}
return(false);
}
