Flags

[semagnum]

I would like to draw areas that I'd like to block light:

• rectangles
• circles
• convex hull

[semagnum]

Might need an extra input - an origin of light (lamp object, 3D cursor, camera?). Otherwise, the direction must be based on existing light sources. May not be arbitrary or deterministic.

[semagnum]

Could do a convex hull. Given grease pencil points and the user selects a given lamp or hull:

light_source_points = a convex hull of points surrounding the lamp (where it could emit from)
draw a line from each light source point to each grease pencil point
At a given factor (0.0 is at the light source, 1.0 is at the grease pencil surface):
  cut_points = list of points given by "slicing" through lines
  hull = convex hull from cut_points
return hull as the shadow card

Can use this code online as a template for finding the "slice":

function midpoint(lat1, long1, lat2, long2, per) {
     return [lat1 + (lat2 - lat1) * per, long1 + (long2 - long1) * per];
}