/// <summary>
/// Random direction around the [0,0,1] vector.
/// Normal distribution is used, using required variance.
/// </summary>
/// <param name="rnd">Random generator to be used.</param>
/// <param name="variance">Variance of the deviation angle in radians.</param>
/// <returns></returns>
public static Vector3d RandomDirectionNormal(RandomJames rnd, double variance)
{
// result: [0,0,1] * rotX(deviation) * rotZ(orientation)
double deviation = rnd.Normal(0.0, variance);
double orientation = rnd.RandomDouble(0.0, Math.PI);
Matrix4d mat = Matrix4d.CreateRotationX(deviation) * Matrix4d.CreateRotationZ(orientation);
return(new Vector3d(mat.Row2)); // [0,0,1] * mat
}
/// <summary>
/// Random direction around the givent center vector.
/// Normal distribution is used, using required variance.
/// </summary>
/// <param name="rnd">Random generator to be used.</param>
/// <param name="dir">Central direction.</param>
/// <param name="variance">Variance of the deviation angle in radians.</param>
/// <returns></returns>
public static Vector3d RandomDirectionNormal(RandomJames rnd, Vector3d dir, double variance)
{
// Matrix3d fromz: [0,0,1] -> dir
// Vector4d delta: [0,0,1] * rotX(deviation) * rotZ(orientation)
// result: delta * fromz
dir.Normalize();
Vector3d axis1, axis2;
GetAxes(ref dir, out axis1, out axis2);
Matrix4d fromz = new Matrix4d(new Vector4d(axis1), new Vector4d(axis2), new Vector4d(dir), Vector4d.UnitW);
//fromz.Transpose();
double deviation = rnd.Normal(0.0, variance);
double orientation = rnd.RandomDouble(0.0, Math.PI);
Matrix4d mat = Matrix4d.CreateRotationX(deviation) * Matrix4d.CreateRotationZ(orientation) * fromz;
return(new Vector3d(mat.Row2)); // [0,0,1] * mat
}
/// <summary>
/// Computes one image sample. Internal integration support.
/// </summary>
/// <param name="x">Horizontal coordinate.</param>
/// <param name="y">Vertical coordinate.</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="color">Computed sample color.</param>
/// <returns>Hash-value used for adaptive subsampling.</returns>
public virtual long GetSample( double x, double y, int rank, int total, RandomJames rnd, double[] color )
{
Vector3d p0, p1;
int bands = color.Length;
if ( !scene.Camera.GetRay( x, y, rank, total, rnd, out p0, out p1 ) )
{
Array.Clear( color, 0, bands ); // invalid ray -> black color
return 1L;
}
LinkedList<Intersection> intersections = scene.Intersectable.Intersect( p0, p1 );
Intersection.countRays++;
Intersection i = Intersection.FirstIntersection( intersections, ref p1 );
if ( i == null ) // no intersection -> background color
{
Array.Copy( scene.BackgroundColor, color, bands );
return 0L;
}
// there was at least one intersection
i.Complete();
// hash code for adaptive supersampling:
long hash = i.Solid.GetHashCode();
// apply all the textures fist..
if ( i.Textures != null )
foreach ( ITexture tex in i.Textures )
hash = hash * HASH_TEXTURE + tex.Apply( i, rank, total, rnd );
// terminate if light sources are missing
if ( scene.Sources == null || scene.Sources.Count < 1 )
{
Array.Copy( i.SurfaceColor, color, bands );
return hash;
}
// .. else apply the reflectance model for each source
p1 = -p1;
p1.Normalize();
i.Material = (IMaterial)i.Material.Clone();
i.Material.Color = i.SurfaceColor;
Array.Clear( color, 0, bands );
foreach ( ILightSource source in scene.Sources )
{
Vector3d dir;
double[] intensity = source.GetIntensity( i, rank, total, rnd, out dir );
if ( intensity != null )
{
double[] reflection = i.ReflectanceModel.ColorReflection( i, dir, p1, ReflectionComponent.ALL );
if ( reflection != null )
{
for ( int b = 0; b < bands; b++ )
color[ b ] += intensity[ b ] * reflection[ b ];
hash = hash * HASH_LIGHT + source.GetHashCode();
}
}
}
return hash;
}
/// <summary>
/// Computes one image sample. Internal integration support.
/// </summary>
/// <param name="x">Horizontal coordinate.</param>
/// <param name="y">Vertical coordinate.</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="color">Computed sample color.</param>
/// <returns>Hash-value used for adaptive subsampling.</returns>
public override long GetSample( double x, double y, int rank, int total, RandomJames rnd, double[] color )
{
// initial color = black
Array.Clear( color, 0, color.Length );
Vector3d p0, p1;
if ( !scene.Camera.GetRay( x, y, rank, total, rnd, out p0, out p1 ) )
return 11L;
long hash = shade( 0, 1.0, ref p0, ref p1, rank, total, rnd, color );
return hash;
}
/// <summary>
/// Recursive shading function - computes color contribution of the given ray (shot from the
/// origin 'p0' into direction vector 'p1''). Recursion is stopped
/// by a hybrid method: 'importance' and 'level' are checked.
/// Internal integration support.
/// </summary>
/// <param name="level">Current recursion depth.</param>
/// <param name="importance">Importance of the current ray.</param>
/// <param name="p0">Ray origin.</param>
/// <param name="p1">Ray direction vector.</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="color">Result color.</param>
/// <returns>Hash-value (ray sub-signature) used for adaptive subsampling.</returns>
protected virtual long shade( int level, double importance, ref Vector3d p0, ref Vector3d p1,
int rank, int total, RandomJames rnd, double[] color )
{
int bands = color.Length;
LinkedList<Intersection> intersections = scene.Intersectable.Intersect( p0, p1 );
Intersection.countRays++;
Intersection i = Intersection.FirstIntersection( intersections, ref p1 );
int b;
if ( i == null ) // no intersection -> background color
{
Array.Copy( scene.BackgroundColor, color, bands );
return 1L;
}
// there was at least one intersection
i.Complete();
// hash code for adaptive supersampling:
long hash = i.Solid.GetHashCode();
// apply all the textures fist..
if ( i.Textures != null )
foreach ( ITexture tex in i.Textures )
hash = hash * HASH_TEXTURE + tex.Apply( i, rank, total, rnd );
p1 = -p1; // viewing vector
p1.Normalize();
if ( scene.Sources == null || scene.Sources.Count < 1 )
// no light sources at all
Array.Copy( i.SurfaceColor, color, bands );
else
{
// apply the reflectance model for each source
i.Material = (IMaterial)i.Material.Clone();
i.Material.Color = i.SurfaceColor;
Array.Clear( color, 0, bands );
foreach ( ILightSource source in scene.Sources )
{
Vector3d dir;
double[] intensity = source.GetIntensity( i, rank, total, rnd, out dir );
if ( intensity != null )
{
if ( DoShadows && !dir.Equals( Vector3d.Zero ) )
{
intersections = scene.Intersectable.Intersect( i.CoordWorld, dir );
Intersection.countRays++;
Intersection si = Intersection.FirstIntersection( intersections, ref dir );
// Better shadow testing: intersection between 0.0 and 1.0 kills the lighting
if ( si != null && !si.Far( 1.0, ref dir ) ) continue;
}
double[] reflection = i.ReflectanceModel.ColorReflection( i, dir, p1, ReflectionComponent.ALL );
if ( reflection != null )
{
for ( b = 0; b < bands; b++ )
color[ b ] += intensity[ b ] * reflection[ b ];
hash = hash * HASH_LIGHT + source.GetHashCode();
}
}
}
}
// check the recursion depth:
if ( level++ >= MaxLevel ||
!DoReflections && !DoRefractions )
return hash; // no further recursion
Vector3d r;
double maxK;
double[] comp = new double[ bands ];
double newImportance;
if ( DoReflections ) // trying to shoot a reflected ray..
{
Geometry.SpecularReflection( ref i.Normal, ref p1, out r );
double[] ks = i.ReflectanceModel.ColorReflection( i, p1, r, ReflectionComponent.SPECULAR_REFLECTION );
if ( ks != null )
{
maxK = ks[ 0 ];
for ( b = 1; b < bands; b++ )
if ( ks[ b ] > maxK )
maxK = ks[ b ];
newImportance = importance * maxK;
if ( newImportance >= MinImportance ) // do compute the reflected ray
{
hash += HASH_REFLECT * shade( level, newImportance, ref i.CoordWorld, ref r, rank, total, rnd, comp );
for ( b = 0; b < bands; b++ )
color[ b ] += ks[ b ] * comp[ b ];
}
}
}
if ( DoRefractions ) // trying to shoot a refracted ray..
{
maxK = i.Material.Kt; // simple solution, no influence of reflectance model yet
newImportance = importance * maxK;
if ( newImportance < MinImportance )
return hash;
// refracted ray:
if ( (r = Geometry.SpecularRefraction( i.Normal, i.Material.n, p1 )) == null )
return hash;
hash += HASH_REFRACT * shade( level, newImportance, ref i.CoordWorld, ref r, rank, total, rnd, comp );
for ( b = 0; b < bands; b++ )
color[ b ] += maxK * comp[ b ];
}
return hash;
}
/// <summary>
/// Renders the given rectangle into the given raster image.
/// Has to be re-entrant since this code is started in multiple parallel threads.
/// </summary>
/// <param name="image">Pre-initialized raster image.</param>
/// <param name="sel">Selector for this working thread.</param>
/// <param name="rnd">Thread-specific random generator.</param>
public virtual void RenderRectangle( Bitmap image, int x1, int y1, int x2, int y2, ThreadSelector sel, RandomJames rnd )
{
bool lead = sel( 0L );
if ( lead &&
ProgressData != null )
lock ( ProgressData )
{
ProgressData.Finished = 0.0f;
ProgressData.Message = "";
}
double[] color = new double[ 3 ]; // pixel color
// run several phases of image rendering:
int cell = 32; // cell size
while ( cell > 1 && cell > Adaptive )
cell >>= 1;
int initCell = cell;
int x, y;
bool xParity, yParity;
float total = (x2 - x1) * (y2 - y1);
long counter = 0L;
long units = 0;
do // do one phase
{
for ( y = y1, yParity = false;
y < y2; // one image row
y += cell, yParity = !yParity )
for ( x = x1, xParity = false;
x < x2; // one image cell
x += cell, xParity = !xParity )
if ( cell == initCell ||
xParity || yParity ) // process the cell
{
if ( !sel( counter++ ) )
continue;
// determine sample color ..
RenderPixel( x, y, color, rnd );
if ( Gamma <= 0.001 )
for ( int b = 0; b < color.Length; b++ )
color[ b ] = Arith.Clamp( color[ b ], 0.0, 1.0 );
// .. and render it:
Color c = Color.FromArgb( (int)(color[ 0 ] * 255.0),
(int)(color[ 1 ] * 255.0),
(int)(color[ 2 ] * 255.0) );
lock ( image )
{
if ( cell == 1 )
image.SetPixel( x, y, c );
else
{
int xMax = x + cell;
if ( xMax > x2 )
xMax = x2;
int yMax = y + cell;
if ( yMax > y2 )
yMax = y2;
for ( int iy = y; iy < yMax; iy++ )
for ( int ix = x; ix < xMax; ix++ )
image.SetPixel( ix, iy, c );
}
}
if ( (++units & 63L) == 0L &&
ProgressData != null )
lock ( ProgressData )
{
if ( !ProgressData.Continue )
return;
if ( lead )
{
ProgressData.Finished = counter / total;
ProgressData.Sync( image );
}
}
}
}
while ( (cell >>= 1) > 0 ); // do one phase
}
/// <summary>
/// Ray-generator. Internal integration support.
/// </summary>
/// <param name="x">Origin position within a viewport (horizontal coordinate).</param>
/// <param name="y">Origin position within a viewport (vertical coordinate).</param>
/// <param name="rank">Rank of this ray, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of rays (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="p0">Ray origin.</param>
/// <param name="p1">Ray direction vector.</param>
/// <returns>True if the ray (viewport position) is valid.</returns>
public bool GetRay( double x, double y, int rank, int total, RandomJames rnd, out Vector3d p0, out Vector3d p1 )
{
return GetRay( x, y, out p0, out p1 );
}
/// <summary>
/// Renders the single pixel of an image.
/// </summary>
/// <param name="x">Horizontal coordinate.</param>
/// <param name="y">Vertical coordinate.</param>
/// <param name="color">Computed pixel color.</param>
/// <param name="rnd">Shared random generator.</param>
public virtual void RenderPixel( int x, int y, double[] color, RandomJames rnd )
{
ImageFunction.GetSample( x + 0.5, y + 0.5, color );
// gamma-encoding:
if ( Gamma > 0.001 )
{ // gamma-encoding and clamping
double g = 1.0 / Gamma;
for ( int b = 0; b < color.Length; b++ )
color[ b ] = Arith.Clamp( Math.Pow( color[ b ], g ), 0.0, 1.0 );
}
// else: no gamma, no clamping (for HDRI)
}
/// <summary>
/// Renders the given rectangle into the given raster image.
/// </summary>
/// <param name="image">Pre-initialized raster image.</param>
/// <param name="rnd">Shared random generator.</param>
public virtual void RenderRectangle( Bitmap image, int x1, int y1, int x2, int y2, RandomJames rnd )
{
RenderRectangle( image, x1, y1, x2, y2, ( n ) => true, rnd );
}
public SamplingState( RectangleLightSource src, RandomJames _rnd )
{
source = src;
rnd = _rnd;
permU = new RandomJames.Permutation();
permV = new RandomJames.Permutation();
rank = total = 0;
}
/// <summary>
/// Returns intensity (incl. color) of the source contribution to the given scene point.
/// Internal integration support.
/// </summary>
/// <param name="intersection">Scene point (only world coordinates and normal vector are needed).</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="dir">Direction to the source is set here (zero vector for omnidirectional source).</param>
/// <returns>Intensity vector in current color space or null if the point is not lit.</returns>
public double[] GetIntensity( Intersection intersection, int rank, int total, RandomJames rnd, out Vector3d dir )
{
return GetIntensity( intersection, out dir );
}
/// <summary>
/// Returns intensity (incl. color) of the source contribution to the given scene point.
/// Internal integration support.
/// </summary>
/// <param name="intersection">Scene point (only world coordinates and normal vector are needed).</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="dir">Direction to the source is set here (zero vector for omnidirectional source). Not normalized!</param>
/// <returns>Intensity vector in current color space or null if the point is not lit.</returns>
public override double[] GetIntensity( Intersection intersection, int rank, int total, RandomJames rnd, out Vector3d dir )
{
if ( rnd == null )
return GetIntensity( intersection, out dir );
SamplingState ss;
lock ( states )
{
if ( !states.TryGetValue( rnd.GetHashCode(), out ss ) )
{
ss = new SamplingState( this, rnd );
states.Add( rnd.GetHashCode(), ss );
}
}
// generate a [new] sample:
ss.generateSample( rank, total );
dir = ss.sample - intersection.CoordWorld;
if ( Vector3d.Dot( dir, intersection.Normal ) <= 0.0 )
return null;
if ( Dim == null || Dim.Length < 3 ) return intensity;
double dist = dir.Length;
double dimCoef = 1.0 / (Dim[0] + dist * (Dim[1] + dist * Dim[2]));
int bands = intensity.Length;
double[] result = new double[ bands ];
for ( int i = 0; i < bands; i++ )
result[ i ] = intensity[ i ] * dimCoef;
return result;
}
/// <summary>
/// Apply the relevant value-modulation in the given Intersection instance.
/// Internal integration support.
/// </summary>
/// <param name="inter">Data object to modify.</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <returns>Hash value (texture signature) for adaptive subsampling.</returns>
public long Apply( Intersection inter, int rank, int total, RandomJames rnd )
{
return Apply( inter );
}
/// <summary>
/// Renders the single pixel of an image.
/// </summary>
/// <param name="x">Horizontal coordinate.</param>
/// <param name="y">Vertical coordinate.</param>
/// <param name="color">Computed pixel color.</param>
/// <param name="rnd">Shared random generator.</param>
public override void RenderPixel( int x, int y, double[] color, RandomJames rnd )
{
Debug.Assert( color != null );
Debug.Assert( rnd != null );
int bands = color.Length;
int b;
Array.Clear( color, 0, bands );
double[] tmp = new double[ bands ];
int i, j, ord;
double step = 1.0 / superXY;
double amplitude = Jittering * step;
double origin = 0.5 * (step - amplitude);
double x0, y0;
for ( j = ord = 0, y0 = y + origin; j++ < superXY; y0 += step )
for ( i = 0, x0 = x + origin; i++ < superXY; x0 += step )
{
ImageFunction.GetSample( x0 + amplitude * rnd.UniformNumber(),
y0 + amplitude * rnd.UniformNumber(),
ord++, Supersampling, rnd, tmp );
for ( b = 0; b < bands; b++ )
color[ b ] += tmp[ b ];
}
double mul = step / superXY;
if ( Gamma > 0.001 )
{ // gamma-encoding and clamping
double g = 1.0 / Gamma;
for ( b = 0; b < bands; b++ )
color[ b ] = Arith.Clamp( Math.Pow( color[ b ] * mul, g ), 0.0, 1.0 );
}
else // no gamma, no clamping (for HDRI)
for ( b = 0; b < bands; b++ )
color[ b ] *= mul;
}
