inline Vec3fa AnisotropicBlinn__eval(const AnisotropicBlinn* This, const Vec3fa& wo, const Vec3fa& wi)
{
const float cosThetaI = dot(wi,This->dz);
/* reflection */
if (cosThetaI > 0.0f) {
const Vec3fa wh = normalize(wi + wo);
return This->Kr * AnisotropicBlinn__eval(This,wh) * abs(cosThetaI);
}
/* transmission */
else {
const Vec3fa wh = normalize(reflect(wi,This->dz) + wo);
return This->Kt * AnisotropicBlinn__eval(This,wh) * abs(cosThetaI);
}
}
inline Vec3fa AnisotropicBlinn__sample(const AnisotropicBlinn* This, const Vec3fa& wo, Vec3fa& wi, const float sx, const float sy, const float sz)
{
//wi = Vec3fa(reflect(normalize(wo),normalize(dz)),1.0f); return Kr;
//wi = Vec3fa(neg(wo),1.0f); return Kt;
const Vec3fa wh = AnisotropicBlinn__sample(This,sx,sy);
//if (dot(wo,wh) < 0.0f) return Vec3fa(0.0f,0.0f);
/* reflection */
if (sz < This->side) {
wi = Vec3fa(reflect(wo,Vec3fa(wh)),wh.w*This->side);
const float cosThetaI = dot(Vec3fa(wi),This->dz);
return This->Kr * AnisotropicBlinn__eval(This,Vec3fa(wh)) * abs(cosThetaI);
}
/* transmission */
else {
wi = Vec3fa(reflect(reflect(wo,Vec3fa(wh)),This->dz),wh.w*(1-This->side));
const float cosThetaI = dot(Vec3fa(wi),This->dz);
return This->Kt * AnisotropicBlinn__eval(This,Vec3fa(wh)) * abs(cosThetaI);
}
}
/* task that renders a single screen tile */
Vec3fa renderPixelPathTrace(float x, float y, const Vec3fa& vx, const Vec3fa& vy, const Vec3fa& vz, const Vec3fa& p)
{
RandomSampler sampler;
RandomSampler_init(sampler, x, y, g_accu_count);
x += RandomSampler_get1D(sampler);
y += RandomSampler_get1D(sampler);
float time = RandomSampler_get1D(sampler);
/* initialize ray */
RTCRay2 ray;
ray.org = p;
ray.dir = normalize(x*vx + y*vy + vz);
ray.tnear = 0.0f;
ray.tfar = inf;
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.primID = RTC_INVALID_GEOMETRY_ID;
ray.mask = -1;
ray.time = time;
ray.filter = nullptr;
Vec3fa color = Vec3fa(0.0f);
Vec3fa weight = Vec3fa(1.0f);
size_t depth = 0;
while (true)
{
/* terminate ray path */
if (reduce_max(weight) < 0.01 || depth > 20)
return color;
/* intersect ray with scene and gather all hits */
rtcIntersect(g_scene,*((RTCRay*)&ray));
/* exit if we hit environment */
if (ray.geomID == RTC_INVALID_GEOMETRY_ID)
return color + weight*Vec3fa(g_ambient_intensity);
/* calculate transmissivity of hair */
AnisotropicBlinn brdf;
float tnear_eps = 0.0001f;
ISPCGeometry* geometry = g_ispc_scene->geometries[ray.geomID];
if (geometry->type == HAIR_SET)
{
/* calculate tangent space */
const Vec3fa dx = normalize(ray.Ng);
const Vec3fa dy = normalize(cross(ray.dir,dx));
const Vec3fa dz = normalize(cross(dy,dx));
/* generate anisotropic BRDF */
AnisotropicBlinn__Constructor(&brdf,hair_Kr,hair_Kt,dx,20.0f,dy,2.0f,dz);
brdf.Kr = hair_Kr;
Vec3fa p = evalBezier(ray.geomID,ray.primID,ray.u);
tnear_eps = 1.1f*p.w;
}
else if (geometry->type == TRIANGLE_MESH)
{
ISPCTriangleMesh* mesh = (ISPCTriangleMesh*) geometry;
ISPCTriangle* triangle = &mesh->triangles[ray.primID];
OBJMaterial* material = (OBJMaterial*) &g_ispc_scene->materials[triangle->materialID];
if (dot(ray.dir,ray.Ng) > 0) ray.Ng = neg(ray.Ng);
/* calculate tangent space */
const Vec3fa dz = normalize(ray.Ng);
const Vec3fa dx = normalize(cross(dz,ray.dir));
const Vec3fa dy = normalize(cross(dz,dx));
/* generate isotropic BRDF */
AnisotropicBlinn__Constructor(&brdf,Vec3fa(1.0f),Vec3fa(0.0f),dx,1.0f,dy,1.0f,dz);
}
/* sample directional light */
RTCRay2 shadow;
shadow.org = ray.org + ray.tfar*ray.dir;
shadow.dir = neg(Vec3fa(g_dirlight_direction));
shadow.tnear = tnear_eps;
shadow.tfar = inf;
shadow.time = time;
Vec3fa T = occluded(g_scene,shadow);
Vec3fa c = AnisotropicBlinn__eval(&brdf,neg(ray.dir),neg(Vec3fa(g_dirlight_direction)));
color = color + weight*c*T*Vec3fa(g_dirlight_intensity);
#if 1
/* sample BRDF */
Vec3fa wi;
float ru = RandomSampler_get1D(sampler);
float rv = RandomSampler_get1D(sampler);
float rw = RandomSampler_get1D(sampler);
c = AnisotropicBlinn__sample(&brdf,neg(ray.dir),wi,ru,rv,rw);
if (wi.w <= 0.0f) return color;
/* calculate secondary ray and offset it out of the hair */
float sign = dot(Vec3fa(wi),brdf.dz) < 0.0f ? -1.0f : 1.0f;
ray.org = ray.org + ray.tfar*ray.dir + sign*tnear_eps*brdf.dz;
ray.dir = Vec3fa(wi);
ray.tnear = 0.001f;
ray.tfar = inf;
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.primID = RTC_INVALID_GEOMETRY_ID;
ray.mask = -1;
ray.time = time;
ray.filter = nullptr;
weight = weight * c/wi.w;
#else
/* continue with transparency ray */
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.tnear = 1.001f*ray.tfar;
ray.tfar = inf;
weight *= brdf.Kt;
#endif
depth++;
}
return color;
}
/* task that renders a single screen tile */
Vec3fa renderPixelPathTrace(float x, float y, const Vec3fa& vx, const Vec3fa& vy, const Vec3fa& vz, const Vec3fa& p)
{
int seed = 21344*x+121233*y+234532*g_accu_count;
float time = frand(seed);
/* initialize ray */
RTCRay2 ray;
ray.org = p;
ray.dir = normalize(x*vx + y*vy + vz);
ray.tnear = 0.0f;
ray.tfar = inf;
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.primID = RTC_INVALID_GEOMETRY_ID;
ray.mask = -1;
ray.time = time;
ray.filter = NULL;
Vec3fa color = Vec3fa(0.0f);
Vec3fa weight = Vec3fa(1.0f);
size_t depth = 0;
while (true)
{
/* terminate ray path */
if (reduce_max(weight) < 0.01 || depth > 20)
return color;
/* intersect ray with scene and gather all hits */
rtcIntersect(g_scene,*((RTCRay*)&ray)); // FIXME: use (RTCRay&) cast
/* exit if we hit environment */
if (ray.geomID == RTC_INVALID_GEOMETRY_ID)
return color + weight*Vec3fa(g_ambient_intensity);
/* calculate transmissivity of hair */
AnisotropicBlinn brdf;
float tnear_eps = 0.0001f;
if (ray.geomID < g_ispc_scene->numHairSets)
{
/* calculate tangent space */
const Vec3fa dx = normalize(ray.Ng);
const Vec3fa dy = normalize(cross(ray.dir,dx));
const Vec3fa dz = normalize(cross(dy,dx));
/* generate anisotropic BRDF */
AnisotropicBlinn__Constructor(&brdf,hair_Kr,hair_Kt,dx,20.0f,dy,2.0f,dz);
brdf.Kr = hair_Kr;
Vec3fa p = evalBezier(ray.geomID,ray.primID,ray.u);
tnear_eps = 1.1f*p.w;
}
else
{
int meshID = ray.geomID-g_ispc_scene->numHairSets;
ISPCMesh* mesh = g_ispc_scene->meshes[meshID];
ISPCTriangle* triangle = &mesh->triangles[ray.primID];
ISPCMaterial* material = &g_ispc_scene->materials[triangle->materialID];
if (material->illum == 1)
{
/* calculate tangent space */
const Vec3fa dx = normalize(Vec3fa(mesh->normals[triangle->v0]));
const Vec3fa dy = normalize(cross(ray.dir,dx));
const Vec3fa dz = normalize(cross(dy,dx));
/* generate anisotropic BRDF */
AnisotropicBlinn__Constructor(&brdf,hair_Kr,hair_Kt,dx,20.0f,dy,2.0f,dz);
brdf.Kr = hair_Kr;
tnear_eps = 1.1f*mesh->texcoords[triangle->v0].x;
}
else
{
if (dot(ray.dir,ray.Ng) > 0) ray.Ng = neg(ray.Ng);
/* calculate tangent space */
const Vec3fa dz = normalize(ray.Ng);
const Vec3fa dx = normalize(cross(dz,ray.dir));
const Vec3fa dy = normalize(cross(dz,dx));
/* generate isotropic BRDF */
AnisotropicBlinn__Constructor(&brdf,Vec3fa(1.0f),Vec3fa(0.0f),dx,1.0f,dy,1.0f,dz);
}
}
/* sample directional light */
RTCRay2 shadow;
shadow.org = ray.org + ray.tfar*ray.dir;
shadow.dir = neg(Vec3fa(g_dirlight_direction));
shadow.tnear = tnear_eps;
shadow.tfar = inf;
shadow.time = time;
Vec3fa T = occluded(g_scene,shadow);
Vec3fa c = AnisotropicBlinn__eval(&brdf,neg(ray.dir),neg(Vec3fa(g_dirlight_direction)));
color = color + weight*c*T*Vec3fa(g_dirlight_intensity); // FIXME: use += operator
#if 1
/* sample BRDF */
Vec3fa wi;
c = AnisotropicBlinn__sample(&brdf,neg(ray.dir),wi,frand(seed),frand(seed),frand(seed));
if (wi.w <= 0.0f) return color;
/* calculate secondary ray and offset it out of the hair */
float sign = dot(Vec3fa(wi),brdf.dz) < 0.0f ? -1.0f : 1.0f;
ray.org = ray.org + ray.tfar*ray.dir + sign*tnear_eps*brdf.dz;
ray.dir = Vec3fa(wi);
ray.tnear = 0.001f;
ray.tfar = inf;
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.primID = RTC_INVALID_GEOMETRY_ID;
ray.mask = -1;
ray.time = time;
ray.filter = NULL;
weight = weight * c/wi.w; // FIXME: use *= operator
#else
/* continue with transparency ray */
ray.geomID = RTC_INVALID_GEOMETRY_ID;
ray.tnear = 1.001f*ray.tfar;
ray.tfar = inf;
weight *= brdf.Kt;
#endif
depth++;
}
return color;
}