public override bool Render()
{
// Render scene
var o = new Vector3F(0.0f, 0.0f, -5.0f);
// Initialize timer
var msecs = Environment.TickCount;
// Render remaining lines
for (var lineY = _currLine; lineY < (Height); lineY++)
{
_sx = _worldX1;
// Render pixels for current line
for (var lineX = 0; lineX < Width; lineX++)
{
// Fire primary ray
var dir = new Vector3F(_sx, _sy, 0.0f) - o;
dir.Normalize();
var r = new Ray(o, dir);
var acc = Raytrace(r, 1);
var red = (int)(acc.X * 256);
var green = (int)(acc.Y * 256);
var blue = (int)(acc.Z * 256);
if (red > 255) red = 255;
if (green > 255) green = 255;
if (blue > 255) blue = 255;
PixelBuffer[_pPos++] = (uint)((red << 16) + (green << 8) + blue);
_sx += _deltaX;
}
_sy += _deltaY;
// See if we've been working to long already
if ((Environment.TickCount - msecs) > 100)
{
// return control to windows so the screen gets updated
_currLine = lineY + 1;
return false;
}
}
// all done
return true;
}
public override IntersectionResult Intersect(Ray ray, ref float refDistance)
{
var tMin = float.NegativeInfinity;
var tMax = float.PositiveInfinity;
for (var i = 0; i < 3; i++)
{
var t1 = (Min[i] - ray.Origin[i]) / ray.Direction[i];
var t2 = (Max[i] - ray.Origin[i]) / ray.Direction[i];
tMin = Math.Max(tMin, Math.Min(t1, t2));
tMax = Math.Min(tMax, Math.Max(t1, t2));
}
if (tMax >= tMin && tMax >= 0) return IntersectionResult.Hit;
return IntersectionResult.Miss;
}
public override IntersectionResult Intersect(Ray ray, ref float refDistance)
{
var d = Vector3F.Dot(Normal, ray.Direction);
if (Math.Abs(d) > Tolerance)
{
var distance = -(Vector3F.Dot(Normal, ray.Origin) + Distance) / d;
if (distance > 0.0f)
{
if (distance < refDistance)
{
refDistance = distance;
return IntersectionResult.Hit;
}
}
}
return IntersectionResult.Miss;
}
public override IntersectionResult Intersect(Ray ray, ref float distance)
{
var vector = ray.Origin - Center;
var b = -Vector3F.Dot(vector, ray.Direction);
var det = (b * b) - Vector3F.Dot(vector, vector) + SquareRadius;
var returnValue = IntersectionResult.Miss;
if (det > 0)
{
det = (float)Math.Sqrt(det);
var i1 = b - det;
var i2 = b + det;
if (i2 > 0.0f)
{
if (i1 < 0.0f)
{
if (i2 < distance)
{
distance = i2;
returnValue = IntersectionResult.InPrimitive;
}
}
else
{
if (i1 < distance)
{
distance = i1;
returnValue = IntersectionResult.Hit;
}
}
}
}
return returnValue;
}
protected override Color Raytrace(Ray ray, int depth)
{
var distance = MaxDistance;
var acc = Color.Black;
// Trace primary ray
Primitive primitive = null;
if (depth > MaxDepth) return Color.Black;
foreach (var currentPrimitive in Scene.Primitives)
{
var res = currentPrimitive.Intersect(ray, ref distance);
if (res != 0)
{
primitive = currentPrimitive;
}
}
// No hit, terminate ray
if (primitive == null) return Color.Black;
// Handle intersection
if (primitive.IsLight)
{
// We hit a light, stop tracing
return Color.White;
}
// Determine color at point of intersection
var intersectionPoint = ray.Origin + ray.Direction * distance;
// Trace lights
foreach (var currentPrimitive in Scene.Primitives.Where(x => x.IsLight))
{
var light = currentPrimitive;
// Calculate diffuse shading;
var lightSource = ((SpherePrimitive)light).Center - intersectionPoint;
lightSource.Normalize();
var normal = primitive.GetNormal(intersectionPoint);
if (primitive.Material.Diffuse > 0)
{
// Check for normals facing away from the light (dot < 0)
var dot = normal.Dot(lightSource);
if (dot > 0)
{
var diff = dot * primitive.Material.Diffuse;
// Add diffuse component to ray color
acc += diff * primitive.Material.Color * light.Material.Color;
}
}
}
// Calculate reflection
var reflection = primitive.Material.Reflection;
if (reflection > 0.0f)
{
var normal = primitive.GetNormal(intersectionPoint);
var r = ray.Direction - 2.0f * ray.Direction.Dot(normal) * normal;
if (depth < MaxDepth)
{
var newRay = new Ray(intersectionPoint + r * Epsilon, r);
var reflectionColor = Raytrace(newRay, depth + 1);
acc += reflection * reflectionColor * primitive.Material.Color;
}
}
return acc;
}
protected override Color Raytrace(Ray ray, int depth)
{
var distance = MaxDistance;
// Depth too high, terminate ray
if (depth >= MaxDepth) return Color.Black;
Primitive primitive = null;
foreach (var currentPrimitive in Scene.Primitives)
{
var res = currentPrimitive.Intersect(ray, ref distance);
if (res != 0)
{
primitive = currentPrimitive;
}
}
// No hit, terminate ray
if (primitive == null) return Color.Black;
if (primitive.IsLight) return Color.White;
var material = primitive.Material;
var emittance = material.Color;
var intersectionPoint = ray.Origin + ray.Direction * distance;
var direction = primitive.GetNormal(intersectionPoint) + new Vector3F((float)_random.NextDouble());
var newRay = new Ray(intersectionPoint, direction);
var cosTheta = newRay.Direction.Dot(intersectionPoint);
var brdf = 2 * material.Reflection * cosTheta;
var reflected = Raytrace(newRay, depth + 1);
return emittance + (brdf * reflected);
}
