/// standard object services ---------------------------------------------------
public Scene(StreamReader infile, Vector eyePosition)
{
// read and condition default sky and ground values
skyEmission = new Vector(infile);
groundReflection = new Vector(infile);
skyEmission = skyEmission.Clamp(Vector.ZERO, skyEmission);
groundReflection = skyEmission * groundReflection.Clamp(Vector.ZERO, Vector.ONE);
triangles = new List<Triangle>();
emitters = new List<Triangle>();
// read objects
while (infile.EndOfStream == false)
{
Triangle t = new Triangle(infile);
if (t.Area != 0)
triangles.Add(t);
}
// find emitting triangles
foreach (Triangle t in triangles)
{
if (!t.Emitivity.IsZero() && (t.Area > 0.0f))
{
emitters.Add(t);
if (emitters.Count >= (1 << MAX_EMITTERS_P))
break;
}
}
// make index
octtree = new Spatial(eyePosition, triangles);
}
/// standard object services ---------------------------------------------------
public Camera(StreamReader infile)
{
// read and condition view definition
ViewPosition = new Vector(infile);
viewDirection = new Vector(infile);
viewAngle = infile.ReadFloat();
viewDirection = viewDirection.Unitize();
if (viewDirection.IsZero())
viewDirection = new Vector(0.0f, 0.0f, 1.0f);
if (viewAngle < 10) viewAngle = 10;
if (viewAngle > 160) viewAngle = 160;
viewAngle *= (float)(Math.PI / 180);
// make other directions of frame
up = new Vector(0.0f, 1.0f, 0.0f);
right = up.Cross(viewDirection).Unitize();
if (!right.IsZero())
up = viewDirection.Cross(right).Unitize();
else
{
up = new Vector(0.0f, 0.0f, viewDirection[1] < 0.0f ? 1.0f : -1.0f);
right = up.Cross(viewDirection).Unitize();
}
} // Camera
public Vector GetDefaultEmission(Vector backDirection)
{
// sky for downward ray, ground for upward ray
if (backDirection[1] < 0)
return skyEmission;
return groundReflection;
}
Triangle[] triangles = null; // isBranch = false
#endregion Fields
#region Constructors
public Spatial(Vector eyePosition, List<Triangle> items)
{
// set overall bound
// accommodate eye position
// (makes tracing algorithm simpler)
for (int i = 6; i-- > 0; bound[i] = eyePosition[i % 3]) ;
// accommodate all items
foreach (Triangle item in items)
{
float[] itemBound = item.GetBound();
// accommodate item
for (int j = 0; j < 6; ++j)
{
if ((bound[j] > itemBound[j]) ^ (j > 2))
bound[j] = itemBound[j];
}
}
// make cubical
float maxSize = 0.0f;
for (int i = 0; i < 3; ++i)
maxSize = Math.Max(maxSize, bound[3 + i] - bound[i]);
for (int i = 0; i < 3; ++i)
bound[3 + i] = Math.Max(bound[3 + i], bound[i] + maxSize);
// make cell tree
Construct(items, 0);
}
/// <summary>
/// Create image based on size from stream
/// </summary>
/// <param name="infile"></param>
public Image(int w , int h)
{
// read width and height
Width = w;
Height = h;
// clamp width and height
Width = Width < 1 ? 1 : (Width > 10000 ? 10000 : Width);
Height = Height < 1 ? 1 : (Height > 10000 ? 10000 : Height);
pixels = new Vector[Width, Height];
for (int i = 0; i < Width; ++i)
for (int j = 0; j < Height; ++j)
pixels[i, j] = new Vector();
}
/// <summary>
/// Create image based on size from stream
/// </summary>
/// <param name="infile"></param>
public Image(StreamReader infile)
{
// read width and height
Width = (int)infile.ReadFloat();
Height = (int)infile.ReadFloat();
// clamp width and height
Width = Width < 1 ? 1 : (Width > 10000 ? 10000 : Width);
Height = Height < 1 ? 1 : (Height > 10000 ? 10000 : Height);
pixels = new Vector[Width, Height];
for (int i = 0; i < Width; ++i)
for (int j = 0; j < Height; ++j)
pixels[i, j] = new Vector();
}
Vector SampleEmitters(Vector rayDirection, SurfacePoint surfacePoint, Sampler random)
{
Vector radiance;
// single emitter sample, ideal diffuse BRDF:
// reflected = (emitivity * solidangle) * (emitterscount) *
// (cos(emitdirection) / pi * reflectivity)
// -- SurfacePoint does the first and last parts (in separate methods)
// get position on an emitter
Vector emitterPosition;
Triangle emitter;
scene.GetEmitter(random, out emitterPosition, out emitter);
// check an emitter was found
if (null != emitter)
{
// make direction to emit point
Vector emitDirection = (emitterPosition - surfacePoint.Position).Unitize();
// send shadow ray
Triangle hitObject;
Vector hitPosition;
scene.GetIntersection(surfacePoint.Position, emitDirection, surfacePoint.Item, out hitObject, out hitPosition);
StatsCounter.RayTraced();
// if unshadowed, get inward emission value
Vector emissionIn = null;
if ((null == hitObject) || (emitter == hitObject))
emissionIn = new SurfacePoint(emitter, emitterPosition).GetEmission(surfacePoint.Position, -emitDirection, true);
else
emissionIn = new Vector();
// get amount reflected by surface
radiance = surfacePoint.GetReflection(emitDirection, emissionIn * scene.GetEmittersCount(), -rayDirection);
}
else
radiance = new Vector();
return radiance;
}
public Vector GetRadiance(Vector rayOrigin, Vector rayDirection, Sampler random, Triangle lastHit)
{
// intersect ray with scene
Triangle pHitObject;
Vector hitPosition;
scene.GetIntersection(rayOrigin, rayDirection, lastHit, out pHitObject, out hitPosition);
Vector radiance;
if (null != pHitObject)
{
// make surface point of intersection
SurfacePoint surfacePoint = new SurfacePoint(pHitObject, hitPosition);
// local emission only for first-hit
if (lastHit != null)
radiance = Vector.ZERO;
else
radiance = surfacePoint.GetEmission(rayOrigin, -rayDirection, false);
// add emitter sample
radiance = radiance + SampleEmitters(rayDirection, surfacePoint, random);
// add recursive reflection
//
// single hemisphere sample, ideal diffuse BRDF:
// reflected = (inradiance * pi) * (cos(in) / pi * color) * reflectance
// -- reflectance magnitude is 'scaled' by the russian roulette, cos is
// importance sampled (both done by SurfacePoint), and the pi and 1/pi
// cancel out
Vector nextDirection;
Vector color;
// check surface bounces ray, recurse
if (surfacePoint.GetNextDirection(random, -rayDirection, out nextDirection, out color))
radiance = radiance + (color * GetRadiance(surfacePoint.Position, nextDirection, random, surfacePoint.Item));
}
else // no hit: default/background scene emission
radiance = scene.GetDefaultEmission(-rayDirection);
return radiance;
}
/// <summary>
/// Construct a new triangle from a stream
/// </summary>
/// <param name="infile"></param>
public Triangle(StreamReader infile)
{
// read three geometry points
verts[0] = new Vector(infile);
verts[1] = new Vector(infile);
verts[2] = new Vector(infile);
// read and condition quality
Reflectivity = new Vector(infile).Clamp(Vector.ZERO, Vector.ONE);
Emitivity = new Vector(infile).Clamp(Vector.ZERO, Vector.MAX);
MaterialId = infile.ReadInt();
// some item caching
edge1 = verts[1] - verts[0];
edge2 = verts[2] - verts[0];
// make area, Tangent, normal, deltas
MakeTangent();
MakeNormal();
MakeArea();
}
public Vector Clamp(Vector min, Vector max)
{
float xn = Math.Min(Math.Max(x, min.x), max.x);
float yn = Math.Min(Math.Max(y, min.y), max.y);
float zn = Math.Min(Math.Max(z, min.z), max.z);
return new Vector(xn, yn, zn);
}
float CalculateToneMapping(Vector[,] pixels, float divider)
{
// calculate log mean luminance
float logMeanLuminance = 1e-4f;
float sumOfLogs = 0.0f;
foreach (Vector p in pixels)
{
float Y = p.Dot(RGB_LUMINANCE) * divider;
sumOfLogs += (float)Math.Log10(Y > 1e-4f ? Y : 1e-4f);
}
logMeanLuminance = (float)Math.Pow(10.0f, sumOfLogs / pixels.Length);
// (what do these mean again? (must check the tech paper...))
float a = 1.219f + (float)Math.Pow(DISPLAY_LUMINANCE_MAX * 0.25f, 0.4f);
float b = 1.219f + (float)Math.Pow(logMeanLuminance, 0.4f);
return (float)Math.Pow(a / b, 2.5f) / DISPLAY_LUMINANCE_MAX;
}
public void AddToPixel(int x, int y, Vector radiance)
{
#if PARALLEL
lock (locker)
#endif
pixels[x, Height - 1 - y] += radiance;
}
void MakeTangent()
{
if (Tangent == null)
Tangent = (verts[1] - verts[0]).Unitize();
}
/*
* @implementation
* Adapted from:
* <cite>'Fast, Minimum Storage Ray-Triangle Intersection'
* Moller, Trumbore;
* Journal Of Graphics Tools, v2n1p21, 1997.
* http://www.acm.org/jgt/papers/MollerTrumbore97/</cite>
*/
public bool GetIntersection(Vector rayOrigin, Vector rayDirection, ref float hitDistance)
{
// begin calculating determinant - also used to calculate U parameter
Vector pvec = rayDirection.Cross(edge2);
// if determinant is near zero, ray lies in plane of triangle
float det = edge1.Dot(pvec);
const float EPSILON = 0.000001f;
if ((det > -EPSILON) && (det < EPSILON))
return false;
float inv_det = 1.0f / det;
// calculate distance from vertex 0 to ray origin
Vector tvec = rayOrigin - verts[0];
// calculate U parameter and test bounds
float u = tvec.Dot(pvec) * inv_det;
if ((u < 0.0f) || (u > 1.0f))
return false;
// prepare to test V parameter
Vector qvec = tvec.Cross(edge1);
// calculate V parameter and test bounds
float v = rayDirection.Dot(qvec) * inv_det;
if ((v < 0.0f) || (u + v > 1.0f))
return false;
// calculate t, ray intersects triangle
hitDistance = edge2.Dot(qvec) * inv_det;
// only allow intersections in the forward ray direction
return hitDistance >= 0.0f;
}
/// <summary>
/// Copy constructor
/// </summary>
public Vector(Vector a)
{
x = a.x;
y = a.y;
z = a.z;
}
public float Dot(Vector v)
{
return (x * v.x) + (y * v.y) + (z * v.z);
}
public void GetEmitter(Sampler random, out Vector position, out Triangle triangle)
{
if (emitters.Count != 0)
{
// select emitter
// not using lower bits, by treating the random as fixed-point i.f bits
int index = ((((int)(int.MaxValue*random.GetNextSample()) & ((1 << MAX_EMITTERS_P) - 1)) * emitters.Count) >> MAX_EMITTERS_P);
// get position on triangle
position = emitters[index].GetSamplePoint(random);
triangle = emitters[index];
}
else
{
position = Vector.ZERO;
triangle = null;
}
}
public void GetIntersection(
Vector rayOrigin, Vector rayDirection, Triangle lastHit,
out Triangle pHitObject, out Vector hitPosition, Vector pStart)
{
hitPosition = null;
pHitObject = null;
// is branch: step through subcells and recurse
if (isBranch)
{
if (pStart == null)
pStart = rayOrigin;
// find which subcell holds ray origin (ray origin is inside cell)
int subCell = 0;
for (int i = 3; i-- > 0; )
{
// compare dimension with center
if (pStart[i] >= ((bound[i] + bound[i + 3]) * 0.5f))
subCell |= 1 << i;
}
// step through intersected subcells
Vector cellPosition = new Vector(pStart);
for (; ; )
{
if (null != spatial[subCell])
{
// intersect subcell
spatial[subCell].GetIntersection(rayOrigin, rayDirection, lastHit, out pHitObject, out hitPosition, cellPosition);
// exit if item hit
if (null != pHitObject)
break;
}
// find next subcell ray moves to
// (by finding which face of the corner ahead is crossed first)
int axis = 2;
float[] step = new float[3]; // todo - move this allocation?
for (int i = 3; i-- > 0; axis = step[i] < step[axis] ? i : axis)
{
bool high = ((subCell >> i) & 1) != 0;
float face = (rayDirection[i] < 0.0f) ^ high ? bound[i + ((high ? 1 : 0) * 3)] : (bound[i] + bound[i + 3]) * 0.5f;
// distance to face
// (div by zero produces infinity, which is later discarded)
step[i] = (face - rayOrigin[i]) / rayDirection[i];
}
// leaving branch if: subcell is low and direction is negative,
// or subcell is high and direction is positive
if ((((subCell >> axis) & 1) != 0) ^ (rayDirection[axis] < 0.0f))
break;
// move to (outer face of) next subcell
cellPosition = rayOrigin + (rayDirection * step[axis]);
subCell = subCell ^ (1 << axis);
}
}
else
{ // is leaf: exhaustively intersect contained items
float nearestDistance = float.MaxValue;
// step through items
foreach (Triangle item in triangles)
{
// avoid false intersection with surface just come from
if (item != lastHit)
{
// intersect ray with item, and inspect if nearest so far
float distance = float.MaxValue;
if (item.GetIntersection(rayOrigin, rayDirection, ref distance) && (distance < nearestDistance))
{
// check intersection is inside cell bound (with tolerance)
Vector hit = rayOrigin + (rayDirection * distance);
float t = Triangle.TOLERANCE;
if ((bound[0] - hit[0] <= t) && (hit[0] - bound[3] <= t) &&
(bound[1] - hit[1] <= t) && (hit[1] - bound[4] <= t) &&
(bound[2] - hit[2] <= t) && (hit[2] - bound[5] <= t))
{
pHitObject = item;
nearestDistance = distance;
hitPosition = hit;
}
}
}
}
}
}
public static Vector Unitize(Vector v)
{
float length = (float)Math.Sqrt((v.x * v.x) + (v.y * v.y) + (v.z * v.z));
if (length == 0)
return Vector.ZERO;
float inv = 1.0f / length;
return new Vector(v.x * inv, v.y * inv, v.z * inv);
}
public static float Dot(Vector u, Vector v)
{
return (u.x * v.x) + (u.y * v.y) + (u.z * v.z);
}
public static Vector Cross(Vector u, Vector v)
{
return new Vector((u.y * v.z) - (u.z * v.y),
(u.z * v.x) - (u.x * v.z),
(u.x * v.y) - (u.y * v.x));
}
public Vector Cross(Vector v)
{
return new Vector((y * v.z) - (z * v.y),
(z * v.x) - (x * v.z),
(x * v.y) - (y * v.x));
}
public void GetIntersection(
Vector rayOrigin, Vector rayDirection, Triangle lastHit,
out Triangle pHitObject, out Vector hitPosition)
{
octtree.GetIntersection(rayOrigin, rayDirection, lastHit, out pHitObject, out hitPosition, null);
}
