private void generateFixedSamples(Vector3[] samples, Color[] colors)
{
for (int i = 0; i < samples.Length; i++)
{
double randX = (double)i / (double)samples.Length;
double randY = QMC.halton(0, i);
int x = 0;
while (randX >= colHistogram[x] && x < colHistogram.Length - 1)
{
x++;
}
float[] rowHistogram = imageHistogram[x];
int y = 0;
while (randY >= rowHistogram[y] && y < rowHistogram.Length - 1)
{
y++;
}
// sample from (x, y)
float u = (float)((x == 0) ? (randX / colHistogram[0]) : ((randX - colHistogram[x - 1]) / (colHistogram[x] - colHistogram[x - 1])));
float v = (float)((y == 0) ? (randY / rowHistogram[0]) : ((randY - rowHistogram[y - 1]) / (rowHistogram[y] - rowHistogram[y - 1])));
float px = ((x == 0) ? colHistogram[0] : (colHistogram[x] - colHistogram[x - 1]));
float py = ((y == 0) ? rowHistogram[0] : (rowHistogram[y] - rowHistogram[y - 1]));
float su = (x + u) / colHistogram.Length;
float sv = (y + v) / rowHistogram.Length;
float invP = (float)Math.Sin(sv * Math.PI) * jacobian / (numSamples * px * py);
samples[i] = getDirection(su, sv);
basis.transform(samples[i]);
colors[i] = texture.getPixel(su, sv).mul(invP);
}
}
/**
* Ambient occlusion routine, returns a value between bright and dark
* depending on the amount of geometric occlusion in the scene.
*
* @param samples number of sample rays
* @param maxDist maximum Length of the rays
* @param bright color when nothing is occluded
* @param dark color when fully occluded
* @return occlusion color
*/
public Color occlusion(int samples, float maxDist, Color bright, Color dark)
{
if (n == null)
{
// in case we got called on a geometry without orientation
return(bright);
}
// make sure we are on the right side of the material
faceforward();
OrthoNormalBasis onb = getBasis();
Vector3 w = new Vector3();
Color result = Color.black();
for (int i = 0; i < samples; i++)
{
float xi = (float)getRandom(i, 0, samples);
float xj = (float)getRandom(i, 1, samples);
float phi = (float)(2 * Math.PI * xi);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(xj);
float cosTheta = (float)Math.Sqrt(1.0f - xj);
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
onb.transform(w);
Ray r = new Ray(p, w);
r.setMax(maxDist);
result.add(Color.blend(bright, dark, traceShadow(r)));
}
return(result.mul(1.0f / samples));
}
public Color getIrradiance(ShadingState state, Color diffuseReflectance)
{
OrthoNormalBasis onb = state.getBasis();
Vector3 w = new Vector3();
Color result = Color.black();
for (int i = 0; i < samples; i++)
{
float xi = (float)state.getRandom(i, 0, samples);
float xj = (float)state.getRandom(i, 1, samples);
float phi = (float)(2 * Math.PI * xi);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(xj);
float cosTheta = (float)Math.Sqrt(1.0f - xj);
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
onb.transform(w);
Ray r = new Ray(state.getPoint(), w);
r.setMax(maxDist);
result.add(Color.blend(bright, dark, state.traceShadow(r)));
}
return(result.mul((float)Math.PI / samples));
}
public void scatterPhoton(ShadingState state, Color power)
{
Color diffuse, specular;
// make sure we are on the right side of the material
state.faceforward();
diffuse = getDiffuse(state);
specular = getSpecular(state);
state.storePhoton(state.getRay().getDirection(), power, diffuse);
float d = diffuse.getAverage();
float r = specular.getAverage();
double rnd = state.getRandom(0, 0, 1);
if (rnd < d)
{
// photon is scattered
power.mul(diffuse).mul(1.0f / d);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * rnd / d;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Sqrt(v);
float s1 = (float)Math.Sqrt(1.0 - v);
Vector3 w = new Vector3((float)Math.Cos(u) * s, (float)Math.Sin(u) * s, s1);
w = onb.transform(w, new Vector3());
state.traceDiffusePhoton(new Ray(state.getPoint(), w), power);
}
else if (rnd < d + r)
{
if (glossyness == 0)
{
float cos = -Vector3.dot(state.getNormal(), state.getRay().getDirection());
power.mul(diffuse).mul(1.0f / d);
// photon is reflected
float dn = 2 * cos;
Vector3 dir = new Vector3();
dir.x = (dn * state.getNormal().x) + state.getRay().getDirection().x;
dir.y = (dn * state.getNormal().y) + state.getRay().getDirection().y;
dir.z = (dn * state.getNormal().z) + state.getRay().getDirection().z;
state.traceReflectionPhoton(new Ray(state.getPoint(), dir), power);
}
else
{
float dn = 2.0f * state.getCosND();
// reflected direction
Vector3 refDir = new Vector3();
refDir.x = (dn * state.getNormal().x) + state.getRay().dx;
refDir.y = (dn * state.getNormal().y) + state.getRay().dy;
refDir.z = (dn * state.getNormal().z) + state.getRay().dz;
power.mul(spec).mul(1.0f / r);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * (rnd - r) / r;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Pow(v, 1 / ((1.0f / glossyness) + 1));
float s1 = (float)Math.Sqrt(1 - s * s);
Vector3 w = new Vector3((float)Math.Cos(u) * s1, (float)Math.Sin(u) * s1, s);
w = onb.transform(w, new Vector3());
state.traceReflectionPhoton(new Ray(state.getPoint(), w), power);
}
}
}
public void getPhoton(double randX1, double randY1, double randX2, double randY2, Point3 p, Vector3 dir, Color power)
{
float z = (float)(1 - 2 * randX2);
float r = (float)Math.Sqrt(Math.Max(0, 1 - z * z));
float phi = (float)(2 * Math.PI * randY2);
float x = r * (float)Math.Cos(phi);
float y = r * (float)Math.Sin(phi);
p.x = center.x + x * radius;
p.y = center.y + y * radius;
p.z = center.z + z * radius;
OrthoNormalBasis basis = OrthoNormalBasis.makeFromW(new Vector3(x, y, z));
phi = (float)(2 * Math.PI * randX1);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(randY1);
float cosTheta = (float)Math.Sqrt(1 - randY1);
dir.x = cosPhi * sinTheta;
dir.y = sinPhi * sinTheta;
dir.z = cosTheta;
basis.transform(dir);
power.set(radiance);
power.mul((float)(Math.PI * Math.PI * 4 * r2));
}
public void ScatterPhoton(ShadingState state, Color power)
{
Color diffuse;
// make sure we are on the right side of the material
if (Vector3.dot(state.getNormal(), state.getRay().getDirection()) > 0.0)
{
state.getNormal().negate();
state.getGeoNormal().negate();
}
diffuse = Color.GRAY;
state.storePhoton(state.getRay().getDirection(), power, diffuse);
float avg = diffuse.getAverage();
double rnd = state.getRandom(0, 0, 1);
if (rnd < avg)
{
// photon is scattered
power.mul(diffuse).mul(1.0f / avg);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * rnd / avg;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Sqrt(v);
float s1 = (float)Math.Sqrt(1.0 - v);
Vector3 w = new Vector3((float)Math.Cos(u) * s, (float)Math.Sin(u) * s, s1);
w = onb.transform(w, new Vector3());
state.traceDiffusePhoton(new Ray(state.getPoint(), w), power);
}
}
public Vector3 getBump(float x, float y, OrthoNormalBasis basis, float scale)
{
Bitmap bitmap = getBitmap();
if (bitmap == null)
{
return(basis.transform(new Vector3(0, 0, 1)));
}
float dx = 1.0f / (bitmap.Width - 1);
float dy = 1.0f / (bitmap.Height - 1);
float b0 = getPixel(x, y).getLuminance();
float bx = getPixel(x + dx, y).getLuminance();
float by = getPixel(x, y + dy).getLuminance();
return(basis.transform(new Vector3(scale * (bx - b0) / dx, scale * (by - b0) / dy, 1)).normalize());
}
public void getSamples(ShadingState state)
{
if (Vector3.dot(sunDirWorld, state.getGeoNormal()) > 0 && Vector3.dot(sunDirWorld, state.getNormal()) > 0)
{
LightSample dest = new LightSample();
dest.setShadowRay(new Ray(state.getPoint(), sunDirWorld));
dest.getShadowRay().setMax(float.MaxValue);
dest.setRadiance(sunColor, sunColor);
dest.traceShadow(state);
state.addSample(dest);
}
int n = state.getDiffuseDepth() > 0 ? 1 : numSkySamples;
for (int i = 0; i < n; i++)
{
// random offset on unit square, we use the infinite version of
// getRandom because the light sampling is adaptive
double randX = state.getRandom(i, 0, n);
double randY = state.getRandom(i, 1, n);
int x = 0;
while (randX >= colHistogram[x] && x < colHistogram.Length - 1)
{
x++;
}
float[] rowHistogram = imageHistogram[x];
int y = 0;
while (randY >= rowHistogram[y] && y < rowHistogram.Length - 1)
{
y++;
}
// sample from (x, y)
float u = (float)((x == 0) ? (randX / colHistogram[0]) : ((randX - colHistogram[x - 1]) / (colHistogram[x] - colHistogram[x - 1])));
float v = (float)((y == 0) ? (randY / rowHistogram[0]) : ((randY - rowHistogram[y - 1]) / (rowHistogram[y] - rowHistogram[y - 1])));
float px = ((x == 0) ? colHistogram[0] : (colHistogram[x] - colHistogram[x - 1]));
float py = ((y == 0) ? rowHistogram[0] : (rowHistogram[y] - rowHistogram[y - 1]));
float su = (x + u) / colHistogram.Length;
float sv = (y + v) / rowHistogram.Length;
float invP = (float)Math.Sin(sv * Math.PI) * jacobian / (n * px * py);
Vector3 localDir = getDirection(su, sv);
Vector3 dir = basis.transform(localDir, new Vector3());
if (Vector3.dot(dir, state.getGeoNormal()) > 0 && Vector3.dot(dir, state.getNormal()) > 0)
{
LightSample dest = new LightSample();
dest.setShadowRay(new Ray(state.getPoint(), dir));
dest.getShadowRay().setMax(float.MaxValue);
Color radiance = getSkyRGB(localDir);
dest.setRadiance(radiance, radiance);
dest.getDiffuseRadiance().mul(invP);
dest.getSpecularRadiance().mul(invP);
dest.traceShadow(state);
state.addSample(dest);
}
}
}
public Vector3 getBump(float x, float y, OrthoNormalBasis basis, float scale)
{
Bitmap bitmap = getBitmap();
float dx = 1.0f / bitmap.getWidth();
float dy = 1.0f / bitmap.getHeight();
float b0 = getPixel(x, y).getLuminance();
float bx = getPixel(x + dx, y).getLuminance();
float by = getPixel(x, y + dy).getLuminance();
return(basis.transform(new Vector3(scale * (b0 - bx), scale * (b0 - by), 1)).normalize());
}
/**
* Computes a phong specular response to the current light samples and
* global illumination.
*
* @param spec specular color
* @param power phong exponent
* @param numRays number of glossy rays to trace
* @return shaded color
*/
public Color specularPhong(Color spec, float power, int numRays)
{
// integrate a phong specular function
Color lr = Color.black();
if (!includeSpecular || spec.isBlack())
{
return(lr);
}
// reflected direction
float dn = 2 * cosND;
Vector3 refDir = new Vector3();
refDir.x = (dn * n.x) + r.dx;
refDir.y = (dn * n.y) + r.dy;
refDir.z = (dn * n.z) + r.dz;
// direct lighting
foreach (LightSample sample in this)
{
float cosNL = sample.dot(n);
float cosLR = sample.dot(refDir);
if (cosLR > 0)
{
lr.madd(cosNL * (float)Math.Pow(cosLR, power), sample.getSpecularRadiance());
}
}
// indirect lighting
if (numRays > 0)
{
int numSamples = getDepth() == 0 ? numRays : 1;
OrthoNormalBasis onb = OrthoNormalBasis.makeFromW(refDir);
float mul = (2.0f * (float)Math.PI / (power + 1)) / numSamples;
for (int i = 0; i < numSamples; i++)
{
// specular indirect lighting
double r1 = getRandom(i, 0, numSamples);
double r2 = getRandom(i, 1, numSamples);
double u = 2 * Math.PI * r1;
double s = (float)Math.Pow(r2, 1 / (power + 1));
double s1 = (float)Math.Sqrt(1 - s * s);
Vector3 w = new Vector3((float)(Math.Cos(u) * s1), (float)(Math.Sin(u) * s1), (float)s);
w = onb.transform(w, new Vector3());
float wn = Vector3.dot(w, n);
if (wn > 0)
{
lr.madd(wn * mul, traceGlossy(new Ray(p, w), i));
}
}
}
lr.mul(spec).mul((power + 2) / (2.0f * (float)Math.PI));
return(lr);
}
public void getPhoton(double randX1, double randY1, double randX2, double randY2, Point3 p, Vector3 dir, Color power)
{
float phi = (float)(2 * Math.PI * randX1);
float s = (float)Math.Sqrt(1.0f - randY1);
dir.x = r * (float)Math.Cos(phi) * s;
dir.y = r * (float)Math.Sin(phi) * s;
dir.z = 0;
basis.transform(dir);
Point3.add(src, dir, p);
dir.set(this.dir);
power.set(radiance).mul((float)Math.PI * r2);
}
public void scatterPhoton(ShadingState state, Color power)
{
// make sure we are on the right side of the material
state.faceforward();
Color d = getDiffuse(state);
state.storePhoton(state.getRay().getDirection(), power, d);
float avgD = d.getAverage();
float avgS = spec.getAverage();
double rnd = state.getRandom(0, 0, 1);
if (rnd < avgD)
{
// photon is scattered diffusely
power.mul(d).mul(1.0f / avgD);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * rnd / avgD;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Sqrt(v);
float s1 = (float)Math.Sqrt(1.0f - v);
Vector3 w = new Vector3((float)Math.Cos(u) * s, (float)Math.Sin(u) * s, s1);
w = onb.transform(w, new Vector3());
state.traceDiffusePhoton(new Ray(state.getPoint(), w), power);
}
else if (rnd < avgD + avgS)
{
// photon is scattered specularly
float dn = 2.0f * state.getCosND();
// reflected direction
Vector3 refDir = new Vector3();
refDir.x = (dn * state.getNormal().x) + state.getRay().dx;
refDir.y = (dn * state.getNormal().y) + state.getRay().dy;
refDir.z = (dn * state.getNormal().z) + state.getRay().dz;
power.mul(spec).mul(1.0f / avgS);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * (rnd - avgD) / avgS;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Pow(v, 1 / (this.power + 1));
float s1 = (float)Math.Sqrt(1 - s * s);
Vector3 w = new Vector3((float)Math.Cos(u) * s1, (float)Math.Sin(u) * s1, s);
w = onb.transform(w, new Vector3());
state.traceReflectionPhoton(new Ray(state.getPoint(), w), power);
}
}
public void getPhoton(double randX1, double randY1, double randX2, double randY2, Point3 p, Vector3 dir, Color power)
{
double rnd = randX1 * totalArea;
int j = areas.Length - 1;
for (int i = 0; i < areas.Length; i++)
{
if (rnd < areas[i])
{
j = i;
break;
}
rnd -= areas[i]; // try next triangle
}
rnd /= areas[j];
randX1 = rnd;
double s = Math.Sqrt(1 - randX2);
float u = (float)(randY2 * s);
float v = (float)(1 - s);
float w = 1 - u - v;
int tri3 = j * 3;
int index0 = 3 * triangles[tri3 + 0];
int index1 = 3 * triangles[tri3 + 1];
int index2 = 3 * triangles[tri3 + 2];
p.x = w * points[index0 + 0] + u * points[index1 + 0] + v * points[index2 + 0];
p.y = w * points[index0 + 1] + u * points[index1 + 1] + v * points[index2 + 1];
p.z = w * points[index0 + 2] + u * points[index1 + 2] + v * points[index2 + 2];
p.x += 0.001f * ngs[j].x;
p.y += 0.001f * ngs[j].y;
p.z += 0.001f * ngs[j].z;
OrthoNormalBasis onb = OrthoNormalBasis.makeFromW(ngs[j]);
u = (float)(2 * Math.PI * randX1);
s = Math.Sqrt(randY1);
onb.transform(new Vector3((float)(Math.Cos(u) * s), (float)(Math.Sin(u) * s), (float)(Math.Sqrt(1 - randY1))), dir);
Color.mul((float)Math.PI * areas[j], radiance, power);
}
public void scatterPhoton(ShadingState state, Color power)
{
Color diffuse;
// make sure we are on the right side of the material
state.faceforward();
diffuse = getDiffuse(state);
state.storePhoton(state.getRay().getDirection(), power, diffuse);
float d = diffuse.getAverage();
float r = d * refl;
double rnd = state.getRandom(0, 0, 1);
if (rnd < d)
{
// photon is scattered
power.mul(diffuse).mul(1.0f / d);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * rnd / d;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Sqrt(v);
float s1 = (float)Math.Sqrt(1.0 - v);
Vector3 w = new Vector3((float)Math.Cos(u) * s, (float)Math.Sin(u) * s, s1);
w = onb.transform(w, new Vector3());
state.traceDiffusePhoton(new Ray(state.getPoint(), w), power);
}
else if (rnd < d + r)
{
float cos = -Vector3.dot(state.getNormal(), state.getRay().getDirection());
power.mul(diffuse).mul(1.0f / d);
// photon is reflected
float dn = 2 * cos;
Vector3 dir = new Vector3();
dir.x = (dn * state.getNormal().x) + state.getRay().getDirection().x;
dir.y = (dn * state.getNormal().y) + state.getRay().getDirection().y;
dir.z = (dn * state.getNormal().z) + state.getRay().getDirection().z;
state.traceReflectionPhoton(new Ray(state.getPoint(), dir), power);
}
}
public Color getIrradiance(ShadingState state, Color diffuseReflectance)
{
if (samples <= 0)
{
return(Color.BLACK);
}
// compute new sample
Color irr = Color.black();
OrthoNormalBasis onb = state.getBasis();
Vector3 w = new Vector3();
int n = state.getDiffuseDepth() == 0 ? samples : 1;
for (int i = 0; i < n; i++)
{
float xi = (float)state.getRandom(i, 0, n);
float xj = (float)state.getRandom(i, 1, n);
float phi = (float)(xi * 2 * Math.PI);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(xj);
float cosTheta = (float)Math.Sqrt(1.0f - xj);
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
onb.transform(w);
ShadingState temp = state.traceFinalGather(new Ray(state.getPoint(), w), i);
if (temp != null)
{
temp.getInstance().prepareShadingState(temp);
if (temp.getShader() != null)
{
irr.add(temp.getShader().getRadiance(temp));
}
}
}
irr.mul((float)Math.PI / n);
return(irr);
}
public void getPhoton(double randX1, double randY1, double randX2, double randY2, Point3 p, Vector3 dir, Color power)
{
double s = Math.Sqrt(1 - randX2);
float u = (float)(randY2 * s);
float v = (float)(1 - s);
float w = 1 - u - v;
int index0 = 3 * meshlight.triangles[tri3 + 0];
int index1 = 3 * meshlight.triangles[tri3 + 1];
int index2 = 3 * meshlight.triangles[tri3 + 2];
p.x = w * meshlight.points[index0 + 0] + u * meshlight.points[index1 + 0] + v * meshlight.points[index2 + 0];
p.y = w * meshlight.points[index0 + 1] + u * meshlight.points[index1 + 1] + v * meshlight.points[index2 + 1];
p.z = w * meshlight.points[index0 + 2] + u * meshlight.points[index1 + 2] + v * meshlight.points[index2 + 2];
p.x += 0.001f * ng.x;
p.y += 0.001f * ng.y;
p.z += 0.001f * ng.z;
OrthoNormalBasis onb = OrthoNormalBasis.makeFromW(ng);
u = (float)(2 * Math.PI * randX1);
s = Math.Sqrt(randY1);
onb.transform(new Vector3((float)(Math.Cos(u) * s), (float)(Math.Sin(u) * s), (float)(Math.Sqrt(1 - randY1))), dir);
Color.mul((float)Math.PI * area, meshlight.radiance, power);
}
public void ScatterPhoton(ShadingState state, Color power)
{
int side = state.getPrimitiveID();
Color kd = null;
switch (side)
{
case 0:
kd = left;
break;
case 1:
kd = right;
break;
case 3:
kd = back;
break;
case 4:
kd = bottom;
break;
case 5:
float lx = state.getPoint().x;
float ly = state.getPoint().y;
if (lx >= lxmin && lx < lxmax && ly >= lymin && ly < lymax && state.getRay().dz > 0)
{
return;
}
kd = top;
break;
default:
Debug.Assert(false);
break;
}
// make sure we are on the right side of the material
if (Vector3.dot(state.getNormal(), state.getRay().getDirection()) > 0)
{
state.getNormal().negate();
state.getGeoNormal().negate();
}
state.storePhoton(state.getRay().getDirection(), power, kd);
double avg = kd.getAverage();
double rnd = state.getRandom(0, 0, 1);
if (rnd < avg)
{
// photon is scattered
power.mul(kd).mul(1 / (float)avg);
OrthoNormalBasis onb = OrthoNormalBasis.makeFromW(state.getNormal());
double u = 2 * Math.PI * rnd / avg;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Sqrt(v);
float s1 = (float)Math.Sqrt(1.0 - v);
Vector3 w = new Vector3((float)Math.Cos(u) * s, (float)Math.Sin(u) * s, s1);
w = onb.transform(w, new Vector3());
state.traceDiffusePhoton(new Ray(state.getPoint(), w), power);
}
}
public void ScatterPhoton(ShadingState state, Color power)
{
// make sure we are on the right side of the material
state.faceforward();
Color d = getDiffuse(state);
state.storePhoton(state.getRay().getDirection(), power, d);
float avgD = d.getAverage();
float avgS = rhoS.getAverage();
double rnd = state.getRandom(0, 0, 1);
if (rnd < avgD)
{
// photon is scattered diffusely
power.mul(d).mul(1.0f / avgD);
OrthoNormalBasis onb = state.getBasis();
double u = 2 * Math.PI * rnd / avgD;
double v = state.getRandom(0, 1, 1);
float s = (float)Math.Sqrt(v);
float s1 = (float)Math.Sqrt(1.0f - v);
Vector3 w = new Vector3((float)Math.Cos(u) * s, (float)Math.Sin(u) * s, s1);
w = onb.transform(w, new Vector3());
state.traceDiffusePhoton(new Ray(state.getPoint(), w), power);
}
else if (rnd < avgD + avgS)
{
// photon is scattered specularly
power.mul(rhoS).mul(1 / avgS);
OrthoNormalBasis basis = state.getBasis();
Vector3 inv = state.getRay().getDirection().negate(new Vector3());
double r1 = rnd / avgS;
double r2 = state.getRandom(0, 1, 1);
float alphaRatio = alphaY / alphaX;
float phi = 0;
if (r1 < 0.25)
{
double val = 4 * r1;
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
}
else if (r1 < 0.5)
{
double val = 1 - 4 * (0.5 - r1);
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
phi = (float)Math.PI - phi;
}
else if (r1 < 0.75)
{
double val = 4 * (r1 - 0.5);
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
phi += (float)Math.PI;
}
else
{
double val = 1 - 4 * (1 - r1);
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
phi = 2 * (float)Math.PI - phi;
}
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float denom = (cosPhi * cosPhi) / (alphaX * alphaX) + (sinPhi * sinPhi) / (alphaY * alphaY);
float theta = (float)Math.Atan(Math.Sqrt(-Math.Log(1 - r2) / denom));
float sinTheta = (float)Math.Sin(theta);
float cosTheta = (float)Math.Cos(theta);
Vector3 h = new Vector3();
h.x = sinTheta * cosPhi;
h.y = sinTheta * sinPhi;
h.z = cosTheta;
basis.transform(h);
Vector3 o = new Vector3();
float ih = Vector3.dot(h, inv);
o.x = 2 * ih * h.x - inv.x;
o.y = 2 * ih * h.y - inv.y;
o.z = 2 * ih * h.z - inv.z;
Ray r = new Ray(state.getPoint(), o);
state.traceReflectionPhoton(r, power);
}
}
public Color GetRadiance(ShadingState state)
{
// make sure we are on the right side of the material
state.faceforward();
OrthoNormalBasis onb = state.getBasis();
// direct lighting and caustics
state.initLightSamples();
state.initCausticSamples();
Color lr = Color.black();
// compute specular contribution
if (state.includeSpecular)
{
Vector3 inv = state.getRay().getDirection().negate(new Vector3());
foreach (LightSample sample in state)
{
float cosNL = sample.dot(state.getNormal());
float fr = brdf(inv, sample.getShadowRay().getDirection(), onb);
lr.madd(cosNL * fr, sample.getSpecularRadiance());
}
// indirect lighting - specular
if (numRays > 0)
{
int n = state.getDepth() == 0 ? numRays : 1;
for (int i = 0; i < n; i++)
{
// specular indirect lighting
double r1 = state.getRandom(i, 0, n);
double r2 = state.getRandom(i, 1, n);
float alphaRatio = alphaY / alphaX;
float phi = 0;
if (r1 < 0.25)
{
double val = 4 * r1;
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
}
else if (r1 < 0.5)
{
double val = 1 - 4 * (0.5 - r1);
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
phi = (float)Math.PI - phi;
}
else if (r1 < 0.75)
{
double val = 4 * (r1 - 0.5);
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
phi += (float)Math.PI;
}
else
{
double val = 1 - 4 * (1 - r1);
phi = (float)Math.Atan(alphaRatio * Math.Tan(Math.PI / 2 * val));
phi = 2 * (float)Math.PI - phi;
}
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float denom = (cosPhi * cosPhi) / (alphaX * alphaX) + (sinPhi * sinPhi) / (alphaY * alphaY);
float theta = (float)Math.Atan(Math.Sqrt(-Math.Log(1 - r2) / denom));
float sinTheta = (float)Math.Sin(theta);
float cosTheta = (float)Math.Cos(theta);
Vector3 h = new Vector3();
h.x = sinTheta * cosPhi;
h.y = sinTheta * sinPhi;
h.z = cosTheta;
onb.transform(h);
Vector3 o = new Vector3();
float ih = Vector3.dot(h, inv);
o.x = 2 * ih * h.x - inv.x;
o.y = 2 * ih * h.y - inv.y;
o.z = 2 * ih * h.z - inv.z;
float no = onb.untransformZ(o);
float ni = onb.untransformZ(inv);
float w = ih * cosTheta * cosTheta * cosTheta * (float)Math.Sqrt(Math.Abs(no / ni));
Ray r = new Ray(state.getPoint(), o);
lr.madd(w / n, state.traceGlossy(r, i));
}
}
lr.mul(rhoS);
}
// add diffuse contribution
lr.add(state.diffuse(getDiffuse(state)));
return(lr);
}
public void getSamples(ShadingState state)
{
if (getNumSamples() <= 0)
{
return;
}
Vector3 wc = Point3.sub(center, state.getPoint(), new Vector3());
float l2 = wc.LengthSquared();
if (l2 <= r2)
{
return; // inside the sphere?
}
// top of the sphere as viewed from the current shading point
float topX = wc.x + state.getNormal().x *radius;
float topY = wc.y + state.getNormal().y *radius;
float topZ = wc.z + state.getNormal().z *radius;
if (state.getNormal().dot(topX, topY, topZ) <= 0)
{
return; // top of the sphere is below the horizon
}
float cosThetaMax = (float)Math.Sqrt(Math.Max(0, 1 - r2 / Vector3.dot(wc, wc)));
OrthoNormalBasis basis = OrthoNormalBasis.makeFromW(wc);
int samples = state.getDiffuseDepth() > 0 ? 1 : getNumSamples();
float scale = (float)(2 * Math.PI * (1 - cosThetaMax));
Color c = Color.mul(scale / samples, radiance);
for (int i = 0; i < samples; i++)
{
// random offset on unit square
double randX = state.getRandom(i, 0, samples);
double randY = state.getRandom(i, 1, samples);
// cone sampling
double cosTheta = (1 - randX) * cosThetaMax + randX;
double sinTheta = Math.Sqrt(1 - cosTheta * cosTheta);
double phi = randY * 2 * Math.PI;
Vector3 dir = new Vector3((float)(Math.Cos(phi) * sinTheta), (float)(Math.Sin(phi) * sinTheta), (float)cosTheta);
basis.transform(dir);
// check that the direction of the sample is the same as the
// normal
float cosNx = Vector3.dot(dir, state.getNormal());
if (cosNx <= 0)
{
continue;
}
float ocx = state.getPoint().x - center.x;
float ocy = state.getPoint().y - center.y;
float ocz = state.getPoint().z - center.z;
float qa = Vector3.dot(dir, dir);
float qb = 2 * ((dir.x * ocx) + (dir.y * ocy) + (dir.z * ocz));
float qc = ((ocx * ocx) + (ocy * ocy) + (ocz * ocz)) - r2;
double[] t = Solvers.solveQuadric(qa, qb, qc);
if (t == null)
{
continue;
}
LightSample dest = new LightSample();
// compute shadow ray to the sampled point
dest.setShadowRay(new Ray(state.getPoint(), dir));
// FIXME: arbitrary bias, should handle as in other places
dest.getShadowRay().setMax((float)t[0] - 1e-3f);
// prepare sample
dest.setRadiance(c, c);
dest.traceShadow(state);
state.addSample(dest);
}
}
public bool update(ParameterList pl, SunflowAPI api)
{
updateBasis(pl.getVector("center", null), pl.getVector("up", null));
numSamples = pl.getInt("samples", numSamples);
string filename = pl.getstring("texture", null);
if (filename != null)
{
texture = TextureCache.getTexture(api.resolveTextureFilename(filename), true);
}
// no texture provided
if (texture == null)
{
return(false);
}
Bitmap b = texture.getBitmap();
if (b == null)
{
return(false);
}
// rebuild histograms if this is a new texture
if (filename != null)
{
imageHistogram = new float[b.Width][];
for (int i = 0; i < imageHistogram.Length; i++)
{
imageHistogram[i] = new float[b.Height];
}
colHistogram = new float[b.Width];
float du = 1.0f / b.Width;
float dv = 1.0f / b.Height;
for (int x = 0; x < b.Width; x++)
{
for (int y = 0; y < b.Height; y++)
{
float u = (x + 0.5f) * du;
float v = (y + 0.5f) * dv;
Color c = texture.getPixel(u, v);
// box filter the image
// c.add(texture.getPixel(u + du, v));
// c.add(texture.getPixel(u + du, v+ dv));
// c.add(texture.getPixel(u, v + dv));
// c.mul(0.25f);
imageHistogram[x][y] = c.getLuminance() * (float)Math.Sin(Math.PI * v);
if (y > 0)
{
imageHistogram[x][y] += imageHistogram[x][y - 1];
}
}
colHistogram[x] = imageHistogram[x][b.Height - 1];
if (x > 0)
{
colHistogram[x] += colHistogram[x - 1];
}
for (int y = 0; y < b.Height; y++)
{
imageHistogram[x][y] /= imageHistogram[x][b.Height - 1];
}
}
for (int x = 0; x < b.Width; x++)
{
colHistogram[x] /= colHistogram[b.Width - 1];
}
jacobian = (float)(2 * Math.PI * Math.PI) / (b.Width * b.Height);
}
// take fixed samples
if (pl.getbool("fixed", samples != null))
{
// Bitmap loc = new Bitmap(filename);
samples = new Vector3[numSamples];
colors = new Color[numSamples];
for (int i = 0; i < numSamples; i++)
{
double randX = (double)i / (double)numSamples;
double randY = QMC.halton(0, i);
int x = 0;
while (randX >= colHistogram[x] && x < colHistogram.Length - 1)
{
x++;
}
float[] rowHistogram = imageHistogram[x];
int y = 0;
while (randY >= rowHistogram[y] && y < rowHistogram.Length - 1)
{
y++;
}
// sample from (x, y)
float u = (float)((x == 0) ? (randX / colHistogram[0]) : ((randX - colHistogram[x - 1]) / (colHistogram[x] - colHistogram[x - 1])));
float v = (float)((y == 0) ? (randY / rowHistogram[0]) : ((randY - rowHistogram[y - 1]) / (rowHistogram[y] - rowHistogram[y - 1])));
float px = ((x == 0) ? colHistogram[0] : (colHistogram[x] - colHistogram[x - 1]));
float py = ((y == 0) ? rowHistogram[0] : (rowHistogram[y] - rowHistogram[y - 1]));
float su = (x + u) / colHistogram.Length;
float sv = (y + v) / rowHistogram.Length;
float invP = (float)Math.Sin(sv * Math.PI) * jacobian / (numSamples * px * py);
samples[i] = getDirection(su, sv);
basis.transform(samples[i]);
colors[i] = texture.getPixel(su, sv).mul(invP);
// loc.setPixel(x, y, Color.YELLOW.copy().mul(1e6f));
}
// loc.save("samples.hdr");
}
else
{
// turn off
samples = null;
colors = null;
}
return(true);
}
public Color getIrradiance(ShadingState state, Color diffuseReflectance)
{
if (samples <= 0)
{
return(Color.BLACK);
}
if (state.getDiffuseDepth() > 0)
{
// do simple path tracing for additional bounces (single ray)
float xi = (float)state.getRandom(0, 0, 1);
float xj = (float)state.getRandom(0, 1, 1);
float phi = (float)(xi * 2 * Math.PI);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(xj);
float cosTheta = (float)Math.Sqrt(1.0f - xj);
Vector3 w = new Vector3();
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
OrthoNormalBasis onb = state.getBasis();
onb.transform(w);
Ray r = new Ray(state.getPoint(), w);
ShadingState temp = state.traceFinalGather(r, 0);
return(temp != null?getGlobalRadiance(temp).copy().mul((float)Math.PI) : Color.BLACK);
}
//rwl.readLock().lockwoot();//fixme
Color irr;
lock (lockObj)
irr = getIrradiance(state.getPoint(), state.getNormal());
//rwl.readLock().unlock();
if (irr == null)
{
// compute new sample
irr = Color.black();
OrthoNormalBasis onb = state.getBasis();
float invR = 0;
float minR = float.PositiveInfinity;
Vector3 w = new Vector3();
for (int i = 0; i < samples; i++)
{
float xi = (float)state.getRandom(i, 0, samples);
float xj = (float)state.getRandom(i, 1, samples);
float phi = (float)(xi * 2 * Math.PI);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(xj);
float cosTheta = (float)Math.Sqrt(1.0f - xj);
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
onb.transform(w);
Ray r = new Ray(state.getPoint(), w);
ShadingState temp = state.traceFinalGather(r, i);
if (temp != null)
{
minR = Math.Min(r.getMax(), minR);
invR += 1.0f / r.getMax();
temp.getInstance().prepareShadingState(temp);
irr.add(getGlobalRadiance(temp));
}
}
irr.mul((float)Math.PI / samples);
invR = samples / invR;
//rwl.writeLock().lockwoot();//fixme
lock (lockObj)
insert(state.getPoint(), state.getNormal(), invR, irr);
//rwl.writeLock().unlock();
// view irr-cache points
// irr = Color.YELLOW.copy().mul(1e6f);
}
return(irr);
}
public Vector3 getNormal(float x, float y, OrthoNormalBasis basis)
{
float[] rgb = getPixel(x, y).getRGB();
return(basis.transform(new Vector3(2 * rgb[0] - 1, 2 * rgb[1] - 1, 2 * rgb[2] - 1)).normalize());
}
public Color getIrradiance(ShadingState state, Color diffuseReflectance)
{
float b = (float)Math.PI * c / diffuseReflectance.getMax();
Color irr = Color.black();
Point3 p = state.getPoint();
Vector3 n = state.getNormal();
int set = (int)(state.getRandom(0, 1, 1) * numSets);
foreach (PointLight vpl in virtualLights[set])
{
Ray r = new Ray(p, vpl.p);
float dotNlD = -(r.dx * vpl.n.x + r.dy * vpl.n.y + r.dz * vpl.n.z);
float dotND = r.dx * n.x + r.dy * n.y + r.dz * n.z;
if (dotNlD > 0 && dotND > 0)
{
float r2 = r.getMax() * r.getMax();
Color opacity = state.traceShadow(r);
Color power = Color.blend(vpl.power, Color.BLACK, opacity);
float g = (dotND * dotNlD) / r2;
irr.madd(0.25f * Math.Min(g, b), power);
}
}
// bias compensation
int nb = (state.getDiffuseDepth() == 0 || numBias <= 0) ? numBias : 1;
if (nb <= 0)
{
return(irr);
}
OrthoNormalBasis onb = state.getBasis();
Vector3 w = new Vector3();
float scale = (float)Math.PI / nb;
for (int i = 0; i < nb; i++)
{
float xi = (float)state.getRandom(i, 0, nb);
float xj = (float)state.getRandom(i, 1, nb);
float phi = (float)(xi * 2 * Math.PI);
float cosPhi = (float)Math.Cos(phi);
float sinPhi = (float)Math.Sin(phi);
float sinTheta = (float)Math.Sqrt(xj);
float cosTheta = (float)Math.Sqrt(1.0f - xj);
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
onb.transform(w);
Ray r = new Ray(state.getPoint(), w);
r.setMax((float)Math.Sqrt(cosTheta / b));
ShadingState temp = state.traceFinalGather(r, i);
if (temp != null)
{
temp.getInstance().prepareShadingState(temp);
if (temp.getShader() != null)
{
float dist = temp.getRay().getMax();
float r2 = dist * dist;
float cosThetaY = -Vector3.dot(w, temp.getNormal());
if (cosThetaY > 0)
{
float g = (cosTheta * cosThetaY) / r2;
// was this path accounted for yet?
if (g > b)
{
irr.madd(scale * (g - b) / g, temp.getShader().GetRadiance(temp));
}
}
}
}
}
return(irr);
}