Terrain Generation

New issue

Refine and improve the terrain generation algorithms. Improve:

Map sizes: define different map size presets (TINY, SMALL, NORMAL, LARGE, XLARGE) to be selected from the main menu
Flatness: maps are generally too bumpy with very little flat land for building placement - specifically, me must ensure that there are flat 3x3 spaces for the rocket at the very least, on all maps
Heights and datum: too rigid
Navigation: ensure that terrains are navigable - different thresholds per terrain resource shape
Water: Make the water level configurable so that the has_water flag is more flexible
Colours and biomes: these are currently fixed; they should be parameterised in the terrain resources files so colours and settings can vary more

Terrain goals:

Terrain manipulation:

OUT OF SCOPE for this milestone, but will be required in the future as some building sizes and shapes will make this necessary. In addition, we will need some form of terrain manipulation to bridge canyons, join islands, etc.

Dependencies:

#	Ticket	Milestone item	Depends on
#158	Map size presets chosen from the main menu	1	—
#159	Make terrain steepness independent of map size	3, "range ignores map size"	—
#160	Per-preset height curve for terracing and flatter land	3, "height distribution", and 2	#159
#161	Give the island preset a main landmass worth landing on	goal: island has more land	#159 (#164 helps)
#162	Guarantee a minimum reachable share of land per preset	4	#159, #160
#163	Guarantee a flat landing site for the colony rocket	2	#162
#164	Configurable water level, with water decided per tile	5	—
#165	River along the canyon floor	goal	#164, #162
#166	Lake in the crater bowl	goal	#164
#167	Rivers across the plains preset	goal	#164, #165