public void resolveContacts(ParticleContact[] contactArray, int numContacts, float duration)
{
int i = 0;
iterationsUsed = 0;
while (iterationsUsed < iterations)
{
float max = float.MaxValue;
int maxIndex = numContacts;
for (i = 0; i < numContacts; i++)
{
float sepVel = contactArray[i].calculateSeparatingVelocity();
if (sepVel < max && (sepVel < 0.0f || contactArray[i].penetration > 0.0f))
{
max = sepVel;
maxIndex = i;
}
}
if (maxIndex == numContacts)
{
break;
}
contactArray[maxIndex].resolve(duration);
Vec3f move1 = contactArray[maxIndex].particleMovement1;
Vec3f move2 = contactArray[maxIndex].particleMovement2;
if (move1 != null)
{
for (i = 0; i < numContacts; i++)
{
if (contactArray[i].particle1 == contactArray[maxIndex].particle1)
{
contactArray[i].penetration -= move1.dot(contactArray[i].contactNormal);
}
else if (contactArray[i].particle1 == contactArray[maxIndex].particle2)
{
contactArray[i].penetration -= move2.dot(contactArray[i].contactNormal);
}
if (contactArray[i].particle2 != null)
{
if (contactArray[i].particle2 == contactArray[maxIndex].particle1)
{
contactArray[i].penetration += move1.dot(contactArray[i].contactNormal);
}
else if (contactArray[i].particle2 == contactArray[maxIndex].particle2)
{
contactArray[i].penetration += move2.dot(contactArray[i].contactNormal);
}
}
}
}
iterationsUsed++;
}
}
public Collision intersect(Vec3f rayorig, Vec3f raydir)
{
Vec3f l = center - rayorig;
float tca = l.dot(raydir);
if (tca < 0)
{
return(new Collision());
}
float d2 = l.dot(l) - tca * tca;
if (d2 > radius2)
{
return(new Collision());
}
float thc = (float)Math.Sqrt(radius2 - d2);
return(new Collision(true, tca - thc, tca + thc));
}
public float calculateSeparatingVelocity()
{
Vec3f relativeVelocity = particle1.Velocity;
if (particle2 != null)
{
relativeVelocity -= particle2.Velocity;
}
return(relativeVelocity.dot(contactNormal));
}
private void resolveVelocity(float duration)
{
float separatingVelocity = calculateSeparatingVelocity();
if (separatingVelocity > 0.0f)
{
return;
}
float newSeparaiongVelocity = -separatingVelocity * restitution;
Vec3f accCausedVelocity = particle1.Acceleration;
if (particle2 != null)
{
accCausedVelocity -= particle2.Acceleration;
}
float accCausedSepVelocity = accCausedVelocity.dot(contactNormal) * duration;
if (accCausedSepVelocity < 0.0f)
{
newSeparaiongVelocity += restitution * accCausedSepVelocity;
if (newSeparaiongVelocity < 0.0f)
{
newSeparaiongVelocity = 0.0f;
}
}
float deltaVelocity = newSeparaiongVelocity - separatingVelocity;
float totalInversMass = particle1.InverseMass;
if (particle2 != null)
{
totalInversMass += particle2.InverseMass;
}
if (totalInversMass <= 0.0f)
{
return;
}
float impulse = deltaVelocity / totalInversMass;
Vec3f impulsePerIMass = contactNormal * impulse;
particle1.Velocity = particle1.Velocity + impulsePerIMass * particle1.InverseMass;
if (particle2 != null)
{
particle2.Velocity = particle2.Velocity + impulsePerIMass * -particle2.InverseMass;
}
}
public void calculateProj(float nearPlane = 0.1f, float farPlane = 1000.0f)
{
polygons_proj = new List <RPolygon>();
foreach (RPolygon poly in polygons_view)
{
Vec3f nearPlaneNormal = new Vec3f(0.0f, 0.0f, 1.0f);
Vec3f nearPlaneP0 = new Vec3f(0.0f, 0.0f, nearPlane);
float sideOfPoint1 = nearPlaneNormal.dot(poly.vertex0.position - nearPlaneP0);
float sideOfPoint2 = nearPlaneNormal.dot(poly.vertex1.position - nearPlaneP0);
float sideOfPoint3 = nearPlaneNormal.dot(poly.vertex2.position - nearPlaneP0);
if (sideOfPoint1 <= 0 || sideOfPoint2 <= 0 || sideOfPoint3 <= 0)
{
poly.visible = false;
}
if (poly.visible)
{
RVertex vertex1 = new RVertex(poly.vertex0);
vertex1.position = new Vec3f(proj * poly.v0);
RVertex vertex2 = new RVertex(poly.vertex1);
vertex2.position = new Vec3f(proj * poly.v1);
RVertex vertex3 = new RVertex(poly.vertex2);
vertex3.position = new Vec3f(proj * poly.v2);
RPolygon newPolygon = new RPolygon(vertex1, vertex2, vertex3, poly.rasterType, poly.texture);
float cosTheta = newPolygon.normalCalc().dot(GlobalDirection.forward3f);
newPolygon.visible = cosTheta >= 0.0f ? false : true;
if (newPolygon.visible)
{
polygons_proj.Add(newPolygon);
}
}
}
}
public void calculateAll(float nearPlane, float farPlane, float width, float height, bool isNDC, bool backFaceCull = true)
{
polygons_raster = new List <RPolygon>();
object sync = new object();
Parallel.ForEach <RPolygon>(
polygons,
poly => {
Mat4f mwv = model;
mwv = mwv * world;
mwv = mwv * view;
RVertex vertex1 = new RVertex(poly.vertex0);
vertex1.position = new Vec3f(mwv * poly.v0);
RVertex vertex2 = new RVertex(poly.vertex1);
vertex2.position = new Vec3f(mwv * poly.v1);
RVertex vertex3 = new RVertex(poly.vertex2);
vertex3.position = new Vec3f(mwv * poly.v2);
Vec3f nearPlaneNormal = new Vec3f(0.0f, 0.0f, 1.0f);
Vec3f nearPlaneP0 = new Vec3f(0.0f, 0.0f, nearPlane);
Vec3f farPlaneNormal = new Vec3f(0.0f, 0.0f, -1.0f);
Vec3f farPlaneP0 = new Vec3f(0.0f, 0.0f, farPlane);
float sideOfPoint1near = nearPlaneNormal.dot(vertex1.position - nearPlaneP0);
float sideOfPoint2near = nearPlaneNormal.dot(vertex2.position - nearPlaneP0);
float sideOfPoint3near = nearPlaneNormal.dot(vertex3.position - nearPlaneP0);
float sideOfPoint1far = farPlaneNormal.dot(vertex1.position - farPlaneP0);
float sideOfPoint2far = farPlaneNormal.dot(vertex2.position - farPlaneP0);
float sideOfPoint3far = farPlaneNormal.dot(vertex3.position - farPlaneP0);
if ((sideOfPoint1near >= 0 && sideOfPoint2near >= 0 && sideOfPoint3near >= 0) && (sideOfPoint1far >= 0 && sideOfPoint2far >= 0 && sideOfPoint3far >= 0))
{
vertex1.position = new Vec3f(proj * vertex1.position);
vertex2.position = new Vec3f(proj * vertex2.position);
vertex3.position = new Vec3f(proj * vertex3.position);
vertex1.position.x = isNDC ? (vertex1.position.x + 1.0f) * 0.5f * width : vertex1.position.x * width;
vertex1.position.y = isNDC ? (vertex1.position.y + 1.0f) * 0.5f * height : vertex1.position.y * height;
vertex2.position.x = isNDC ? (vertex2.position.x + 1.0f) * 0.5f * width : vertex2.position.x * width;
vertex2.position.y = isNDC ? (vertex2.position.y + 1.0f) * 0.5f * height : vertex2.position.y * height;
vertex3.position.x = isNDC ? (vertex3.position.x + 1.0f) * 0.5f * width : vertex3.position.x * width;
vertex3.position.y = isNDC ? (vertex3.position.y + 1.0f) * 0.5f * height : vertex3.position.y * height;
RPolygon newPolygon = new RPolygon(vertex1, vertex2, vertex3, poly.rasterType, poly.texture);
float cosTheta = newPolygon.normalCalc().dot(GlobalDirection.forward3f);
newPolygon.visible = cosTheta >= 0.0f ? false : true;
if (!backFaceCull || newPolygon.visible)
{
newPolygon.sort();
lock (sync) {
polygons_raster.Add(newPolygon);
}
}
}
}
);
}
public static Vec3f trace(Vec3f rayorig, Vec3f raydir, Sphere[] spheres, int depth)
{
float tnear = FAR;
Sphere sphere = null;
for (int i = 0; i < spheres.Length; i++)
{
Collision coll = spheres[i].intersect(rayorig, raydir);
if (coll.collide && coll.t0 < tnear)
{
tnear = coll.t0;
sphere = spheres[i];
}
}
if (sphere == null)
{
return(new Vec3f(2));
}
Vec3f surfaceColor = new Vec3f();
Vec3f phit = rayorig + raydir * tnear;
Vec3f nhit = (phit - sphere.center).normalize();
float bias = 1e-4f;
bool inside = false;
if (raydir.dot(nhit) > 0)
{
nhit = -nhit; inside = true;
}
if ((sphere.transparency > 0 || sphere.reflection > 0) && depth < MAX_RAY_DEPTH)
{
float facingratio = -raydir.dot(nhit);
float fresneleffect = mix((float)Math.Pow(1 - facingratio, 3), 1, 0.1f);
Vec3f refldir = (raydir - nhit * 2 * raydir.dot(nhit)).normalize();
Vec3f reflection = trace(phit + nhit * bias, refldir, spheres, depth + 1);
Vec3f refraction = new Vec3f();
if (sphere.transparency > 0)
{
float ior = 1.1f; float eta = inside ? ior : 1 / ior;
float cosi = -nhit.dot(raydir);
float k = 1 - eta * eta * (1 - cosi * cosi);
Vec3f refrdir = (raydir * eta + nhit * (eta * cosi - (float)Math.Sqrt(k))).normalize();
refraction = trace(phit - nhit * bias, refrdir, spheres, depth + 1);
}
surfaceColor = (
reflection * fresneleffect +
refraction * (1 - fresneleffect) * sphere.transparency) * sphere.surfaceColor;
}
else
{
for (int i = 0; i < spheres.Length; i++)
{
if (spheres[i].emissionColor.x > 0)
{
Vec3f transmission = new Vec3f(1);
Vec3f lightDirection = (spheres[i].center - phit).normalize();
for (int j = 0; j < spheres.Length; j++)
{
if (i != j)
{
Collision jcoll = spheres[j].intersect(phit + nhit * bias, lightDirection);
if (jcoll.collide)
{
transmission = new Vec3f();
break;
}
}
}
surfaceColor += sphere.surfaceColor * transmission *
Math.Max(0, nhit.dot(lightDirection)) * spheres[i].emissionColor;
}
}
}
return(surfaceColor + sphere.emissionColor);
}
public Vec3f trace(Vec3f rayorig, Vec3f raydir, List <Sphere> spheres, int depth)
{
float tnear = INFINITY;
Sphere sphere = null;
//find intersection of this ray with the sphere in the scene
int spCount = spheres.Count();
for (int i = 0; i < spCount; ++i)
{
float t0 = INFINITY;
float t1 = INFINITY;
(bool, float, float)inter = spheres[i].intersect(rayorig, raydir);
if (inter.Item1)
{
t0 = inter.Item2;
t1 = inter.Item3;
if (t0 < 0)
{
t0 = t1;
}
if (t0 < tnear)
{
tnear = t0;
sphere = spheres[i];
}
}
}
//if there's no intersection return black or background color
if (sphere == null)
{
return(new Vec3f(1.0f));
}
Vec3f surfaceColor = new Vec3f(0.0f); //color of the ray/surfaceof the object intersected by the ray
Vec3f phit = rayorig + raydir * tnear; //point of intersection
Vec3f nhit = phit - sphere.center; //normal at the intersection point
nhit.normalize(); //normalize normal direction
//If the normal and the view direction are not opposite to each other
//reverse the normal direction. That also means we are inside the sphere so set
//the inside bool to true. Finally reverse the sign of IdotN which we want
//positive.
float bias = 0.0001f; //add some bias to the point from which we will be tracing
bool inside = false;
if (raydir.dot(nhit) > 0)
{
nhit = -1 * nhit;
inside = true;
}
if ((sphere.transparency > 0 || sphere.reflection > 0) && depth < MAX_RAY_DEPTH)
{
float facingratio = -raydir.dot(nhit);
// change the mix value to tweak the effect
float fresneleffect = mix((float)Math.Pow(1 - facingratio, 3), 1, 0.1f);
// compute reflection direction (not need to normalize because all vectors
// are already normalized)
Vec3f refldir = raydir - nhit * 2 * raydir.dot(nhit);
refldir.normalize();
Vec3f reflection = trace(phit + nhit * bias, refldir, spheres, depth + 1);
Vec3f refraction = new Vec3f(0.0f);
// if the sphere is also transparent compute refraction ray (transmission)
if (sphere.transparency != 0.0f)
{
float ior = 1.1f;
float eta = (inside) ? ior : 1 / ior; // are we inside or outside the surface?
float cosi = -nhit.dot(raydir);
float k = 1 - eta * eta * (1 - cosi * cosi);
Vec3f refrdir = raydir * eta + nhit * (eta * cosi - (float)Math.Sqrt(k));
refrdir.normalize();
refraction = trace(phit - nhit * bias, refrdir, spheres, depth + 1);
}
// the result is a mix of reflection and refraction (if the sphere is transparent)
surfaceColor = (reflection * fresneleffect + refraction * (1.0f - fresneleffect) * sphere.transparency) * sphere.surfaceColor;
}
else
{
// it's a diffuse object, no need to raytrace any further
for (int i = 0; i < spCount; ++i)
{
if (spheres[i].emissionColor.x > 0)
{
// this is a light
Vec3f transmission = new Vec3f(1.0f);
Vec3f lightDirection = spheres[i].center - phit;
lightDirection.normalize();
for (int j = 0; j < spCount; ++j)
{
if (i != j)
{
if (spheres[j].intersect(phit + nhit * bias, lightDirection).Item1)
{
transmission = new Vec3f(0.0f);
break;
}
}
}
surfaceColor += sphere.surfaceColor * transmission * Math.Max(0.0f, nhit.dot(lightDirection)) * spheres[i].emissionColor;
}
}
}
return(surfaceColor + sphere.emissionColor);
}
