This is a summary of where I think we are at with sunlight mechanics. All input welcome for discussing this. Are there things here you like or dislike or have other ideas for?
The biome you are in has some amount of sunlight reaching it. The list of biomes isn’t completely fixed so I’m just using examples of three classes.
In a dark biome (the abyss and the cave, for example) there is no sunlight at all. In these biomes it makes sense to use a bio-luminescent organelle. This organelle turns ATP into light, something like a lantern.
In a light biome (something like a coastal shelf or ocean surface) there are sunspots that are gradient circles. Inside a circle chloroplasts will work, the closer to the center the better they work. Should these circles appear and disappear over about 20-30s? They could grow in size up to a max size and then shrink again.
You can use an eyespot to search for lightspots which are off the edge of your screen. When you point the eyespot in the right direction the edge of the screen glows.
In a super-light biome (like a tide pool) there are lots of really big sunlight gradient circles which overlap and it’s hard to get out of them. Moreover the centers of the circles are too bright and the sunlight will damage your cell. If you have a pigment protein then you reduce any sunlight damage you receive.
As an extension once this is built we can use this code to work out the best pigment colour from light of the star and the atmospheric gas concentrations.
Does this sound like a good package of mechanics that will work well?
In the organelles list we have a “photoreceptor protein”, what should it’s function be? Should it be you can only see the sunspots if you have this protein and if you don’t they are invisible to you? It would then be a precursor for the eyespot.