inline bool Triangle::intersect(Ray& ray, Intersection& intersection) {
vec3 pvec = cross(ray.direction, edge2);
float det = dot(edge1, pvec);
if(det <= 0.0)
return false;
vec3 tvec = ray.origin - vert0;
float u = dot(tvec, pvec);
if(u < 0.0f || u > det)
return false;
vec3 qvec = cross(tvec, edge1);
float v = dot(ray.direction, qvec);
if(v < 0.0f || u + v > det)
return false;
float t = dot(edge2, qvec);
float inv_det = 1.0f / det;
t *= inv_det;
//u *= inv_det;
//v *= inv_det;
if(t >= intersection.getT())
return false;
intersection.set(t, ray.getPosition(t), cross(edge1, edge2), edge1, this);
return true;
}
Color AtmospherePathTracingIntegrator::transmittance( SceneCPtr scene, const Ray &r, bool debug )const
{
Atmosphere::LUTParameters &parms = scene->m_atmosphere->m_parameters;
const Real heightOffset = (Real)parms.R_e+0.1f;
// move to correct height
Ray ray = r;
ray.o += Vector( 0.0f, heightOffset, 0.0f );
// find intersection with outer atmosphere
Real t0,t1;
if (!math::intersectionRaySphere<Real>( ray, (Real)parms.R_a, t0, t1))
return math::Vec3f(1.0f);
if( t1 > ray.tmax )
t1 = ray.tmax;
unsigned numSamples = parms.viewRaySamples*m_numStepsMultiplier;
Real segmentLength = t1 / numSamples;
//Real segmentLength = 200.0f;
//unsigned numSamples = int(t1 / segmentLength);
//Real tCurrent = 0.0;
//math::Vec3f sumR(0.0f), sumM(0.0f);
Real densityR = Real(0.0);
Real densityM = Real(0.0);
for (unsigned i = 0; i < numSamples; ++i)
{
Vector samplePosition = ray.getPosition(i*segmentLength);
Real height = samplePosition.getLength() - (Real)parms.R_e;
Real currentDensityR = exp(-height / parms.h_r)*segmentLength;
Real currentDensityM = exp(-height / parms.h_m)*segmentLength;
densityR += (Real)currentDensityR;
densityM += (Real)currentDensityM;
}
Vector opticalDepth = (Vector)parms.beta_r*densityR + (Vector)parms.beta_m*Real(1.1)*densityM;
return Vector( exp(-opticalDepth.x), exp(-opticalDepth.y), exp(-opticalDepth.z) );
}
// inter_point : Poistion where ray intersected with geometry.
VolumeTracer::Interval VolumeTracer::getInterval(Ray ray, IVolume* volume, vec3 inter_point) {
OBB::IntervalData intersect = volume->getInterval(ray);
if(!intersect.intersected)
return Interval();
vec3 min = intersect.min;
vec3 max = intersect.max;
if(intersect.inside) // If we're inside the box, we have no min, put ray position to min.
min = ray.getPosition();
float dist = glm::distance(min, max);
// If inter_point is within the volume, move it to max
if(glm::distance(min, inter_point) < dist)
max = inter_point;
return Interval(true, min, max);
}
IAccDataStruct::IntersectionData Heightmap::triangleIntersection(Ray ray, Triangle* triangle1, Triangle* triangle2) {
vec3 o = ray.getPosition();
vec3 d = ray.getDirection();
Triangle* closest_tri = NULL;
//float closest_dist = -1;
vec3 closest_pos;
float closest_t = numeric_limits<float>::infinity( );
for(int i = 0; i < 2; i++) {
Triangle* cur_triangle;
switch (i) {
case 0:
cur_triangle = triangle1;
break;
case 1:
cur_triangle = triangle2;
break;
default:
cur_triangle = triangle1;
break;
}
const vector<vec3*> vertices = cur_triangle->getVertices();
vec3 v0 = *(vertices[0]);
vec3 v1 = *(vertices[1]);
vec3 v2 = *(vertices[2]);
vec3 e1 = v1 - v0;
vec3 e2 = v2 - v0;
vec3 s = o - v0;
vec3 dxe2 = cross(d, e2);
vec3 sxe1 = cross(s, e1);
vec3 res = ( 1.0f / dot(dxe2, e1) ) *
vec3( dot(sxe1, e2), dot(dxe2, s), dot(sxe1, d) );
float t = res.x;
float u = res.y;
float v = res.z;
float dist = glm::distance(o, closest_pos);
if(u >= 0 && v >= 0 && u + v <= 1) { // Intersection!
if(t > 0 && t < closest_t) {
closest_tri = cur_triangle;
closest_pos = o + t * d;
//closest_dist = dist;
closest_t = t;
}
}
}
if(closest_t == numeric_limits<float>::infinity( )) {
return IAccDataStruct::IntersectionData::miss();
}
vec3 v1v0 = *(closest_tri->getVertices()[1]) - *(closest_tri->getVertices()[0]);
vec3 v2v1 = *(closest_tri->getVertices()[2]) - *(closest_tri->getVertices()[1]);
vec3 v2v0 = *(closest_tri->getVertices()[2]) - *(closest_tri->getVertices()[0]);
vec3 pv0 = closest_pos - *(closest_tri->getVertices()[0]);
vec3 pv1 = closest_pos - *(closest_tri->getVertices()[1]);
float a = length(cross(v1v0, v2v0));
float a0 = length(cross(v2v1, pv1))/a;
float a1 = length(cross(v2v0, pv0))/a;
float a2 = length(cross(v1v0, pv0))/a;
vec3 inter_normal = a0 * *(closest_tri->getNormals()[0]) +
a1 * *(closest_tri->getNormals()[1]) +
a2 * *(closest_tri->getNormals()[2]);
vec3 v1 = v1v0;
vec3 v2 = v2v1;
if(v1.length() > v2.length()) {
v1 = v2v1;
v1 = v1v0;
}
if(v2.length() > v2v0.length()) {
v2 = v2v0;
}
return IAccDataStruct::IntersectionData(NULL, 0, closest_pos, glm::normalize(inter_normal), vec2(0,0));
}
Color AtmospherePathTracingIntegrator::Li( SceneCPtr scene, RendererCPtr renderer, const Ray &r, Color &transmittance, bool debug) const
{
Debug dd;
Atmosphere::LUTParameters &parms = scene->m_atmosphere->m_parameters;
const Real heightOffset = (Real)parms.R_e+0.1f;
// move to correct height
Ray ray = r;
ray.o += Vector( 0.0f, heightOffset, 0.0f );
// find intersection with outer atmosphere
Real t0,t1;
if (!math::intersectionRaySphere<Real>( ray, (Real)parms.R_a, t0, t1))
return math::Vec3f(1.0f);
if( t1 > ray.tmax )
t1 = ray.tmax;
if( t0 < ray.tmin )
t0 = ray.tmin;
///*
Real maxDist = t1-t0;
//Real stepSize = maxDist/(parms.viewRaySamples);
Real stepSize = 1.0f;
//Real stepSize = m_stepSize;
Vector step = ray.d*stepSize;
Real tend;
Real volSamplePDF;
Vector x;
///*
// uniform sampling ---------------
tend = t0 + math::g_randomNumber.randomFloat()*maxDist;
volSamplePDF = 1.0f/maxDist;
// raymarch to tend and compute transmittance
Real t = t0;// + math::g_randomNumber.randomFloat()*stepSize;
x = ray.getPosition( t );
Real densityR = 0.0f;
Real densityM = 0.0f;
while( t<tend )
{
Real height = x.getLength() - (Real)parms.R_e;
Real currentDensityR = exp(-height / parms.h_r)*stepSize;
Real currentDensityM = exp(-height / parms.h_m)*stepSize;
densityR += currentDensityR;
densityM += currentDensityM;
t += stepSize;
x += step;
};
Vector opticalDepth = (Vector)parms.beta_r*densityR + (Vector)parms.beta_m*Real(1.1)*densityM;
Vector transmittanceView = Vector( exp(-opticalDepth.x), exp(-opticalDepth.y), exp(-opticalDepth.z) );
//*/
/*
// woodcock tracking
Real maxDensity = 6.0f;
Real densityEnd = -log( math::g_randomNumber.randomFloat() ) / maxDensity;
// raymarch to tend and compute transmittance
Real densityR = 0.0f;
Real densityM = 0.0f;
tend = t0;
x = ray.getPosition(tend);
while( (densityR+densityM<maxDensity)&&(tend<t1) )
{
Real height = x.getLength() - (Real)parms.R_e;
Real currentDensityR = exp(-height / parms.h_r)*stepSize;
Real currentDensityM = exp(-height / parms.h_m)*stepSize;
densityR += currentDensityR;
densityM += currentDensityM;
tend += stepSize;
x += step;
};
Vector opticalDepth = (Vector)parms.beta_r*densityR + (Vector)parms.beta_m*Real(1.1)*densityM;
Vector transmittanceView = Vector( exp(-opticalDepth.x), exp(-opticalDepth.y), exp(-opticalDepth.z) );
volSamplePDF = exp(-(densityR+densityM))*maxDensity;
*/
/*
// woodcock tracking2
Real maxDensity = 2.0f;
Real densityEnd = -log( math::g_randomNumber.randomFloat() ) / maxDensity;
// raymarch to tend and compute transmittance
Real densityR = 0.0f;
Real densityM = 0.0f;
tend = t0;
while(tend < t1)
{
tend += -log( math::g_randomNumber.randomFloat() ) / maxDensity;
x = ray.getPosition(tend);
Real height = x.getLength() - (Real)parms.R_e;
Real currentDensityR = exp(-height / parms.h_r);
Real currentDensityM = exp(-height / parms.h_m);
densityR += currentDensityR;
densityM += currentDensityM;
if( math::g_randomNumber.randomFloat() < (currentDensityR+currentDensityM)/maxDensity )
break;
};
Vector opticalDepth = (Vector)parms.beta_r*densityR + (Vector)parms.beta_m*Real(1.1)*densityM;
Vector transmittanceView = Vector( exp(-opticalDepth.x), exp(-opticalDepth.y), exp(-opticalDepth.z) );
volSamplePDF = exp(-(densityR+densityM))*maxDensity;
*/
// ---
Real nu = math::dot( ray.d, (Vector)scene->m_atmosphere->m_sunDirection );
Real phaseR = (Real)(3.0f / (16.0f * Real(MATH_PIf))) * (1.0f + nu * nu);
Real g = (Real)parms.mie_phase_g;
Real phaseM = (3 / (8 * Real(MATH_PI))) * (((1 - g * g) * (1 + nu * nu))/((2 + g * g) * pow(1 + g * g - 2 * g * nu, Real(1.5))));
Color Ls(0.0f);
// single scattering
{
LightCPtr light = scene->m_lights[0];
Vector lx = x - Vector( 0.0f, heightOffset, 0.0f );
Vector wi;
Real pdf;
Ray vis; // visibility ray
Color Li = light->sample_L( lx, wi, pdf, vis );
Color transmittanceLight = renderer->transmittance( scene, vis );
Real height = x.getLength() - (Real)parms.R_e;
Real currentDensityR = exp(-height / parms.h_r)*stepSize;
Real currentDensityM = exp(-height / parms.h_m)*stepSize;
Color tt = transmittanceView*transmittanceLight;
Color sum_r = tt*phaseR*currentDensityR*parms.beta_r;
Color sum_m = tt*phaseM*currentDensityM*parms.beta_m*Real(1.1f);
Ls += Li*(sum_r + sum_m)/pdf;
///*
if( debug )
{
Debug dd;
dd.tend = tend;
dd.transmittance = transmittanceLight;
dd.Li = Ls;
debugData.push_back(dd);
}
//*/
}
transmittance = this->transmittance(scene, r);
return Ls/volSamplePDF;
}
Ray Transform::transform( const Ray &i_ray, const glm::mat4 &i_transform ) {
glm::vec3 position = Transform::transform( i_ray.getPosition(), i_transform );
glm::vec3 direction = Transform::transform( i_ray.getDirection(), i_transform, false );
return Ray( position, direction );
}
