The Geometry Modules

core.opsim_geo

Definitions / declarations for geometrical objects and functions used in DOSSS.

class core.opsim_geo.DOSSSLine(a=None, u=None)

Represents a line of the form P = a + lambda * u where u gives the direction of the line and a is the base of the line. Distances along the line are measured relative to this point.

Parameters:
  • a (DOSSSVector) – Base point of the line. If None, it defaults to (0,0).
  • u (DOSSSVector) – Direction of the line. If None, it defaults to (1,0).
bounded_intersection(l, p1, p2)

Return the intersection of a line l (DOSSSLine) with the current line (DOSSSVector) only if it lies between the points p1 (DOSSSVector) and p2 (DOSSSVector), otherwise returns None.

contains_point(p)

Returns True if point p is part of the line, False otherwise.

get_normal(p)

Returns a line orthogonal to this line through the specified point p (DOSSSVector).

get_point(l)

Return point for lambda value l.

intersect(l)

Returns the intersection of a line with the current line (DOSSSVector) or None if the lines are parallel or identical.

isLambdaPositiveForPoint(p)

Return True if point p (DOSSSVector) is in the positive half space of the line, i.e. lambda is positive. Returns False otherwise.

mirror(l)

Mirror the current line on another line l. The new base point is the intersection of the two lines.

rotate(alpha)

Returns a copy of the current line rotated by an angle alpha (in degrees).

class core.opsim_geo.DOSSSVector(nx=0, ny=0)

A 2d vector class that supports basic arithmetic operations (+, -, *).

Parameters:
  • nx (float) – x-component (optional).
  • ny (float) – y-component (optional).
isNull()

Returns True if vector is identical to zero, False otherwise.

length()

Return length of vector.

rotate(theta)

Rotate vector.

Parameters:theta (float) – Angle in degrees.
Returns:Rotated vector.
setx(x)

Overwrite x-component of vector.

Parameters:x (float) – New value for x-component.
sety(y)

Overwrite y-component of vector.

Parameters:y (float) – New value for y-component.
unit()

Returns a unit vector with the same orientation.

x()

Returns x-component of vector. If absolute value is below 1e-10, it returns 0.

y()

Returns y-component of vector. If absolute value is below 1e-10, it returns 0.

core.opsim_geo.IntersectionWithParabola(line, f)

Calculate the intersection between a line and a parabola.

Parameters:
  • line (DOSSSLine) – The line.
  • f (float) – Focal length of the parabola.
Returns:

Intersection(s) (Sequence of DOSSSVectors of length [0, 1, 2])
core.opsim_geo.IntersectionWithSphere(line, x0, R)

Calculate the intersection between a line and a sphere.

Parameters:
  • line (DOSSSLine) – The line.
  • x0 (DOSSSVector) – Center of the sphere.
  • R (float) – Radius of the sphere.
Returns:

Intersection(s) (Sequence of DOSSSVectors of length [0, 1, 2]).
core.opsim_geo.Snell(u, n, ior=0)

Apply Snell’s law to a vector.

Parameters:
  • u (DOSSSVector) – Incident vector.
  • n (DOSSSVector) – Surface normal vector.
  • ior (float) – Index of refraction of the refracting object (ior != 0). Set to zero to calculate reflected vector.
Returns:

Refracted (ior != 0) or reflected (ior == 0) vector.
core.opsim_geo.getLineThroughPoints(p1, p2)

Create a DOSSSLine object defined by two points p1 (DOSSSVector) and p2 (DOSSSVector).

core.opsim_lightray

Definitions / declarations for light rays for use in DOSSS.

class core.opsim_lightray.DOSSS_LightRay(posx=0, posy=0, ux=1, uy=0)

A light ray class used for raytracing in DOSSS. All coordinates are given in laboratory system.

Parameters:
  • posx (float) – x-coordinate of the base point.
  • posy (float) – y-coordinate of the base point.
  • ux (float) – x-component of the direction vector.
  • uy (float) – y-component of the direction vector.
ContinueRay(dc, px, py, ux, uy)

Calculate the continuation of the light ray beyond the last intersecting object for proper display on screen.

All coordinates are given in DC client system, i.e. range from 0 to size of screen in px.

Parameters:
  • dc (wx.DC) – Paint DC.
  • px (float) – x-coordinate of the base point.
  • py (float) – y-coordinate of the base point.
  • ux (float) – x-component of the direction vector.
  • uy (float) – y-component of the direction vector.
Returns:

Lambda value of intersection with screen boundary (float).
Draw(dc, zoom, ox, oy)

Draw the light ray to the DC client.

Parameters:
  • dc (wx.DC) – Paint DC.
  • zoom (float) – Zoom level, where 1 is no zoom.
  • ox (float) – x-coordinate of origin of current view in laboratory frame.
  • oy (float) – y-coordinate of origin of current view in laboratory frame.
getCurLine()

Returns DOSSSLine object for current part of the beam.

svgstr()

Returns a string in SVG format for exporting to vector format.

core.opsim_lightray.fromLine(l)

Convert a DOSSSLine object into a DOSSS_LightRay object.