Directional Lighting and Penumbra Shadows
GM can set a "light size" in the ambient light configuration. This controls the amount of penumbra in the shadow. Lights are modeled physically as 3d spheres, with penumbra appearing for the left and right edges of walls and top/bottom edges of limited height walls when the light source is above the wall.
GM can change an ambient light to a "directional light", which models a light source such as the sun or moon that is very far away. Moving the light around the scene controls its azimuth and elevation angle, with elevation angle approaching 90º as the light reaches the center of the canvas. GM can also set the solar angle, which controls the amount of penumbra in the shadow. All properties are physically modeled, allowing light to stream across the entire canvas. Lighting animations work as normal, although some are a lot better than others (sunburst, starlight, and fog are pretty good).
Rework of the switching between lighting algorithms in a scene, to avoid reloading the scene.