Class ShadingState

  • All Implemented Interfaces:
    java.lang.Iterable<LightSample>

    public final class ShadingState
    extends java.lang.Object
    implements java.lang.Iterable<LightSample>
    Represents a point to be shaded and provides various options for the shading of this point, including spawning of new rays.
    • Method Detail

      • init

        public final void init()
        Create objects needed for surface shading: point, normal, texture coordinates and basis.
      • shade

        public final Color shade()
        Run the shader at this surface point.
        Returns:
        shaded result
      • faceforward

        public final void faceforward()
        Flip the surface normals to ensure they are facing the current ray. This method also offsets the shading point away from the surface so that new rays will not intersect the same surface again by mistake.
      • getRasterX

        public final float getRasterX()
        Get x coordinate of the pixel being shaded.
        Returns:
        pixel x coordinate
      • getRasterY

        public final float getRasterY()
        Get y coordinate of the pixel being shaded.
        Returns:
        pixel y coordinate
      • getCosND

        public final float getCosND()
        Cosine between the shading normal and the ray. This is set by faceforward().
        Returns:
        cosine between shading normal and the ray
      • isBehind

        public final boolean isBehind()
        Returns true if the ray hit the surface from behind. This is set by faceforward().
        Returns:
        true if the surface was hit from behind.
      • getU

        public final float getU()
        Get u barycentric coordinate of the intersection point.
        Returns:
        u barycentric coordinate
      • getV

        public final float getV()
        Get v barycentric coordinate of the intersection point.
        Returns:
        v barycentric coordinate
      • getW

        public final float getW()
        Get w barycentric coordinate of the intersection point.
        Returns:
        w barycentric coordinate
      • getInstance

        public final Instance getInstance()
        Get the instance which was intersected
        Returns:
        intersected instance object
      • getPrimitiveID

        public final int getPrimitiveID()
        Get the primitive ID which was intersected
        Returns:
        intersected primitive ID
      • transformObjectToWorld

        public Point3 transformObjectToWorld​(Point3 p)
        Transform the given point from object space to world space. A new Point3 object is returned.
        Parameters:
        p - object space position to transform
        Returns:
        transformed position
      • transformWorldToObject

        public Point3 transformWorldToObject​(Point3 p)
        Transform the given point from world space to object space. A new Point3 object is returned.
        Parameters:
        p - world space position to transform
        Returns:
        transformed position
      • transformNormalObjectToWorld

        public Vector3 transformNormalObjectToWorld​(Vector3 n)
        Transform the given normal from object space to world space. A new Vector3 object is returned.
        Parameters:
        n - object space normal to transform
        Returns:
        transformed normal
      • transformNormalWorldToObject

        public Vector3 transformNormalWorldToObject​(Vector3 n)
        Transform the given normal from world space to object space. A new Vector3 object is returned.
        Parameters:
        n - world space normal to transform
        Returns:
        transformed normal
      • transformVectorObjectToWorld

        public Vector3 transformVectorObjectToWorld​(Vector3 v)
        Transform the given vector from object space to world space. A new Vector3 object is returned.
        Parameters:
        v - object space vector to transform
        Returns:
        transformed vector
      • transformVectorWorldToObject

        public Vector3 transformVectorWorldToObject​(Vector3 v)
        Transform the given vector from world space to object space. A new Vector3 object is returned.
        Parameters:
        v - world space vector to transform
        Returns:
        transformed vector
      • getResult

        public final Color getResult()
        Get the result of shading this point
        Returns:
        shaded result
      • addSample

        public final void addSample​(LightSample sample)
        Add the specified light sample to the list of lights to be used
        Parameters:
        sample - a valid light sample
      • getRandom

        public final double getRandom​(int j,
                                      int dim)
        Get a QMC sample from an infinite sequence.
        Parameters:
        j - sample number (starts from 0)
        dim - dimension to sample
        Returns:
        pseudo-random value in [0,1)
      • getRandom

        public final double getRandom​(int j,
                                      int dim,
                                      int n)
        Get a QMC sample from a finite sequence of n elements. This provides better stratification than the infinite version, but does not allow for adaptive sampling.
        Parameters:
        j - sample number (starts from 0)
        dim - dimension to sample
        n - number of samples
        Returns:
        pseudo-random value in [0,1)
      • includeLights

        public final boolean includeLights()
        Checks to see if the shader should include emitted light.
        Returns:
        true if emitted light should be included, false otherwise
      • includeSpecular

        public final boolean includeSpecular()
        Checks to see if the shader should include specular terms.
        Returns:
        true if specular terms should be included, false otherwise
      • getShader

        public final Shader getShader()
        Get the shader to be used to shade this surface.
        Returns:
        shader to be used
      • setShader

        public final void setShader​(Shader shader)
        Record which shader should be executed for the intersected surface.
        Parameters:
        shader - surface shader to use to shade the current intersection point
      • setModifier

        public final void setModifier​(Modifier modifier)
        Record which modifier should be applied to the intersected surface
        Parameters:
        modifier - modifier to use the change this shading state
      • getDepth

        public final int getDepth()
        Get the current total tracing depth. First generation rays have a depth of 0.
        Returns:
        current tracing depth
      • getDiffuseDepth

        public final int getDiffuseDepth()
        Get the current diffuse tracing depth. This is the number of diffuse surfaces reflected from.
        Returns:
        current diffuse tracing depth
      • getReflectionDepth

        public final int getReflectionDepth()
        Get the current reflection tracing depth. This is the number of specular surfaces reflected from.
        Returns:
        current reflection tracing depth
      • getRefractionDepth

        public final int getRefractionDepth()
        Get the current refraction tracing depth. This is the number of specular surfaces refracted from.
        Returns:
        current refraction tracing depth
      • getPoint

        public final Point3 getPoint()
        Get hit point.
        Returns:
        hit point
      • getNormal

        public final Vector3 getNormal()
        Get shading normal at the hit point. This may differ from the geometric normal
        Returns:
        shading normal
      • getUV

        public final Point2 getUV()
        Get texture coordinates at the hit point.
        Returns:
        texture coordinate
      • getGeoNormal

        public final Vector3 getGeoNormal()
        Gets the geometric normal of the current hit point.
        Returns:
        geometric normal of the current hit point
      • getBasis

        public final OrthoNormalBasis getBasis()
        Gets the local orthonormal basis for the current hit point.
        Returns:
        local basis or null if undefined
      • setBasis

        public final void setBasis​(OrthoNormalBasis basis)
        Define the orthonormal basis for the current hit point.
        Parameters:
        basis -
      • getRay

        public final Ray getRay()
        Gets the ray that is associated with this state.
        Returns:
        ray associated with this state.
      • getCameraToWorld

        public final Matrix4 getCameraToWorld()
        Get a transformation matrix that will transform camera space points into world space.
        Returns:
        camera to world transform
      • getWorldToCamera

        public final Matrix4 getWorldToCamera()
        Get a transformation matrix that will transform world space points into camera space.
        Returns:
        world to camera transform
      • getTrianglePoints

        public final boolean getTrianglePoints​(Point3[] p)
        Get the three triangle corners in object space if the hit object is a mesh, returns false otherwise.
        Parameters:
        p - array of 3 points
        Returns:
        true if the points were read succesfully, falseotherwise
      • initLightSamples

        public final void initLightSamples()
        Initialize the use of light samples. Prepares a list of visible lights from the current point.
      • initCausticSamples

        public final void initCausticSamples()
        Add caustic samples to the current light sample set. This method does nothing if caustics are not enabled.
      • traceGlossy

        public final Color traceGlossy​(Ray r,
                                       int i)
        Returns the color obtained by recursively tracing the specified ray. The reflection is assumed to be glossy.
        Parameters:
        r - ray to trace
        i - instance number of this sample
        Returns:
        color observed along specified ray.
      • traceReflection

        public final Color traceReflection​(Ray r,
                                           int i)
        Returns the color obtained by recursively tracing the specified ray. The reflection is assumed to be specular.
        Parameters:
        r - ray to trace
        i - instance number of this sample
        Returns:
        color observed along specified ray.
      • traceRefraction

        public final Color traceRefraction​(Ray r,
                                           int i)
        Returns the color obtained by recursively tracing the specified ray.
        Parameters:
        r - ray to trace
        i - instance number of this sample
        Returns:
        color observed along specified ray.
      • traceTransparency

        public final Color traceTransparency()
        Trace transparency, this is equivalent to tracing a refraction ray in the incoming ray direction.
        Returns:
        color observed behind the current shading point
      • traceShadow

        public final Color traceShadow​(Ray r)
        Trace a shadow ray against the scene, and computes the accumulated opacity along the ray.
        Parameters:
        r - ray to trace
        Returns:
        opacity along the shadow ray
      • storePhoton

        public final void storePhoton​(Vector3 dir,
                                      Color power,
                                      Color diffuse)
        Records a photon at the specified location.
        Parameters:
        dir - incoming direction of the photon
        power - photon power
        diffuse - diffuse reflectance at the given point
      • traceReflectionPhoton

        public final void traceReflectionPhoton​(Ray r,
                                                Color power)
        Trace a new photon from the current location. This assumes that the photon was reflected by a specular surface.
        Parameters:
        r - ray to trace photon along
        power - power of the new photon
      • traceRefractionPhoton

        public final void traceRefractionPhoton​(Ray r,
                                                Color power)
        Trace a new photon from the current location. This assumes that the photon was refracted by a specular surface.
        Parameters:
        r - ray to trace photon along
        power - power of the new photon
      • traceDiffusePhoton

        public final void traceDiffusePhoton​(Ray r,
                                             Color power)
        Trace a new photon from the current location. This assumes that the photon was reflected by a diffuse surface.
        Parameters:
        r - ray to trace photon along
        power - power of the new photon
      • getGlobalRadiance

        public final Color getGlobalRadiance()
        Returns the glboal diffuse radiance estimate given by the current GIEngine if present.
        Returns:
        global diffuse radiance estimate
      • getIrradiance

        public final Color getIrradiance​(Color diffuseReflectance)
        Gets the total irradiance reaching the current point from diffuse surfaces.
        Parameters:
        diffuseReflectance - diffuse reflectance at the current point, can be used for importance tracking
        Returns:
        indirect diffuse irradiance reaching the point
      • traceFinalGather

        public final ShadingState traceFinalGather​(Ray r,
                                                   int i)
        Trace a final gather ray and return the intersection result as a new render state
        Parameters:
        r - ray to shoot
        i - instance of the ray
        Returns:
        new render state object corresponding to the intersection result
      • occlusion

        public final Color occlusion​(int samples,
                                     float maxDist)
        Simple black and white ambient occlusion.
        Parameters:
        samples - number of sample rays
        maxDist - maximum length of the rays
        Returns:
        occlusion color
      • occlusion

        public final Color occlusion​(int samples,
                                     float maxDist,
                                     Color bright,
                                     Color dark)
        Ambient occlusion routine, returns a value between bright and dark depending on the amount of geometric occlusion in the scene.
        Parameters:
        samples - number of sample rays
        maxDist - maximum length of the rays
        bright - color when nothing is occluded
        dark - color when fully occluded
        Returns:
        occlusion color
      • diffuse

        public final Color diffuse​(Color diff)
        Computes a plain diffuse response to the current light samples and global illumination.
        Parameters:
        diff - diffuse color
        Returns:
        shaded result
      • specularPhong

        public final Color specularPhong​(Color spec,
                                         float power,
                                         int numRays)
        Computes a phong specular response to the current light samples and global illumination.
        Parameters:
        spec - specular color
        power - phong exponent
        numRays - number of glossy rays to trace
        Returns:
        shaded color
      • iterator

        public java.util.Iterator<LightSample> iterator()
        Allows iteration over current light samples.
        Specified by:
        iterator in interface java.lang.Iterable<LightSample>
      • getShadowDepth

        public final int getShadowDepth()
      • traceTransparentShadow

        public Color traceTransparentShadow​(float oldMaxT)