public override Vector3 GetIntensity(Ray ray, Intersection intersection, Scene scene)
{
float diff = 0f, spec = 0f;
Material mat = intersection.primitive.material;
bool visible = false;
// Calculate vector from intersection point to light point
Vector3 L = direction;
float NdotL = Vector3.Dot(intersection.normal, L);
// Is the light direction on the same side as the normal?
if (NdotL > 0f)
{
// check the intersection as late as possible:
visible = !scene.DoesIntersect(new Ray(intersection.location, L), float.PositiveInfinity);
if (visible)
{
diff = NdotL;
if (ray.debug)
{
// Add a shadow ray to the debug screen
Ray debugray = new Ray(intersection.location, L);
debugray.debugSurface = ray.debugSurface;
debugray.camerapos = ray.camerapos;
debugray.debugxunit = ray.debugxunit;
debugray.debugyunit = ray.debugyunit;
Raytracer.DrawRayDebug(debugray, null, 0x0000ff);
}
}
}
// Add some specularity
if (mat.isSpecular)
{
Vector3 viewDir = -ray.direction;
Vector3 halfway = (L + viewDir).Normalized();
float NdotH = Vector3.Dot(intersection.normal, halfway);
// Are we on the good side of the normal?
if (NdotH > 0f)
{
// Check if this light is visible from the intersection (calculate if not calculated already)
if (NdotL <= 0f)
{
visible = !scene.DoesIntersect(new Ray(intersection.location, L), float.PositiveInfinity);
}
if (visible)
{
// Use a power law to let this hardness have on effect on the decay of intensity of the white effect
spec = (float)Math.Pow(NdotH, mat.hardness);
}
}
}
// mix the colors, specularity (from light, not reflection) is always white.
Vector3 diffuse = intersection.primitive.GetDiffuseColor(intersection);
return(intensity * (diffuse * diff + Vector3.One * spec));
}
public override Vector3 GetIntensity(Ray ray, Intersection intersection, Scene scene)
{
//Calculate vector from intersection point to light point
Vector3 lightvec = this.position - intersection.location;
//If the best effect of the lightsource on the intersectionpoint is less than half the least visible difference
if (lightvec.LengthSquared > maxIntensity * 512)
{
return(Vector3.Zero);
}
Vector3 lightnormal = Vector3.Normalize(lightvec);
// The light is not inside the cone of angle cosangle
if (Vector3.Dot(-lightnormal, direction) < cosangle)
{
return(Vector3.Zero);
}
float dot = Vector3.Dot(intersection.normal, lightnormal);
// Is the light source on the same side as the normal?
if (dot <= 0f)
{
return(Vector3.Zero); // In this case not.
}
// check the intersection as late as possible:
if (scene.DoesIntersect(new Ray(intersection.location, lightnormal), lightvec.Length))
{
return(Vector3.Zero);
}
if (ray.debug)
{
// Add a shadow ray to the debug screen
Ray debugray = new Ray(intersection.location, lightnormal);
debugray.debugSurface = ray.debugSurface;
debugray.camerapos = ray.camerapos;
debugray.debugxunit = ray.debugxunit;
debugray.debugyunit = ray.debugyunit;
Intersection fakeintersection = new Intersection(this.position, 0, null, Vector3.UnitX);
Raytracer.DrawRayDebug(debugray, fakeintersection, 0x0000ff);
}
// Use inverse square law for intensity at distance lightvec.Length
return(intensity * dot / lightvec.LengthSquared);
}
public override Vector3 GetIntensity(Ray ray, Intersection intersection, Scene scene)
{
float diff = 0f, spec = 0f;
Material mat = intersection.primitive.material;
bool visible = false;
// Calculate vector from intersection point to light point
Vector3 L = position - intersection.location;
// Use inverse square law for intensity at a certain distance
float dist = L.Length, distSq = L.LengthSquared;
// If the best effect of the lightsource on the intersectionpoint is less than half the least visible difference
if (distSq <= maxIntensity * 512)
{
L /= dist;
float NdotL = Vector3.Dot(intersection.normal, L);
// Is the light direction on the same side as the normal?
if (NdotL > 0f)
{
// check the intersection as late as possible:
visible = !scene.DoesIntersect(new Ray(intersection.location, L), dist);
if (visible)
{
diff = NdotL / distSq;
if (ray.debug)
{
// Add a shadow ray to the debug screen
Ray debugray = new Ray(intersection.location, L);
debugray.debugSurface = ray.debugSurface;
debugray.camerapos = ray.camerapos;
debugray.debugxunit = ray.debugxunit;
debugray.debugyunit = ray.debugyunit;
// Fake intersection makes sure the line is drawn from the intersection point up to the light position
Intersection fakeintersection = new Intersection(this.position, 0, null, Vector3.UnitX);
Raytracer.DrawRayDebug(debugray, fakeintersection, 0x0000ff);
}
}
}
// Add some specularity
if (mat.isSpecular)
{
Vector3 viewDir = -ray.direction;
Vector3 halfway = (L + viewDir).Normalized();
float NdotH = Vector3.Dot(intersection.normal, halfway);
// Are we on the good side of the normal?
if (NdotH > 0f)
{
// Check if this light is visible from the intersection (calculate if not calculated already)
if (NdotL <= 0f)
{
visible = !scene.DoesIntersect(new Ray(intersection.location, L), dist);
}
if (visible)
{
// Use a power law to let this hardness have on effect on the decay of intensity of the white effect
spec = ((float)Math.Pow(NdotH, mat.hardness)) / distSq;
}
}
}
}
// mix the colors, specularity (from light, not reflection) is always white.
Vector3 diffuse = intersection.primitive.GetDiffuseColor(intersection);
return(intensity * (diffuse * diff + Vector3.One * spec));
}
