EcoTerrain¶

from acron.vegetation import EcoTerrain

class EcoTerrain¶

Bases:

Bases: TypedReferenceCount

The ground an ecosystem grows on: a heightfield over a rectangle of the world, and optional masks over the same rectangle – moisture (0 dry .. 1 wet), exclusion (1 where nothing may grow: roads, yards, a runway) and water (1 open water). World units are metres, z up.

Images map onto the rectangle with their first row at the north edge (+y, the top of the picture as seen from above) and their first column at the west edge (-x); pixel centres sit on the rectangle’s corners and edges, so a (n+1)-pixel image over n metres has a pixel every metre. A PTA_float heightfield is read the same way (rows north to south). Samples are bilinear; outside the rectangle they clamp to its edge.

Species’ altitude limits read the altitude, `z * scale + offset` (set_altitude; by default the height itself): a game whose hills are 200 m high can map them onto a montane range for its species’ zonation without changing the ground.

Without a moisture mask, moisture is derived from the relief: hollows and valley floors (lower than the ground around them) are wetter, ridges and steep slopes drier, and the ground near water wettest.

Threads: change a terrain from one thread at a time (from Python, as usual). The BLOCKING calls of Ecosystem and GrassField that read it take a snapshot when they start, so changing it while one runs is safe and takes effect from the next call. Non-finite heights, sizes and settings are rejected (an error, the value unchanged), NaN heights read as 0.

Inheritance diagram

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__init__()¶

A flat terrain at z = 0 over the rectangle from `origin` (its south-west corner) spanning `size` metres.

A copy (sharing the grids, which are never changed in place).

clear_exclusion()¶

clear_moisture()¶

clear_water()¶

get_altitude()¶: The altitude at (x, y) (see set_altitude()).

get_altitude_offset()¶

get_altitude_scale()¶

static get_class_type()¶

get_exclusion()¶: The exclusion mask at (x, y) (0 without one).

get_height()¶: The ground’s height at (x, y).

get_max_height()¶

get_min_height()¶

get_moisture()¶: Moisture 0..1 at (x, y): the mask’s, or the relief’s estimate (0.5 on level open ground, wetter in hollows and by water, drier on ridges and steep slopes).

get_normal()¶: The ground’s unit normal at (x, y), from central differences one pixel of the heightfield apart.

get_origin()¶

get_relief_radius()¶

get_size()¶

get_slope()¶: The slope at (x, y) in degrees (0 level, 90 a cliff).

get_water()¶: The water mask at (x, y) (0 without one).

get_x_size()¶

get_y_size()¶

has_exclusion()¶

has_moisture_mask()¶

has_water()¶

property origin → LPoint2f¶

paint_path()¶: Adds a path – a road, a track, a firebreak – to the exclusion mask: the polyline through `points` (x, y pairs, world), `width` metres of full exclusion fading over `verge` metres either side. Without a mask yet, one of `resolution` pixels a side is made over the terrain.

set_altitude()¶: How heights map onto the altitude species’ limits are written in: altitude = z * scale + offset.

set_exclusion()¶: Where nothing grows (1) – roads, yards – from the image’s grey level. Partial values thin the plants out.

set_flat()¶: A level terrain at height `z`.

set_heights()¶

The heights from an image’s grey level (0..1) times `z_scale` plus `z_offset`. A 16-bit greyscale image keeps the full precision.

The heights from `x_size` x `y_size` floats, rows north to south, times `z_scale` plus `z_offset`.

set_moisture()¶: Moisture 0 (dry) .. 1 (wet) from the image’s grey level; replaces the moisture derived from the relief.

set_relief_radius()¶: The radius (m) of the neighbourhood the derived moisture compares a point with: hollows lower than the mean of this disc are wetter.

set_water()¶: Open water (1) from the image’s grey level.

property size → LVecBase2f¶