2D Lighting¶

SimVX provides 2D lighting with point lights, directional lights, and shadow-casting occluders.

Point Lights¶

PointLight2D emits light radially from its position:

from simvx.core import PointLight2D, Vec2

light = PointLight2D(
    position=Vec2(400, 300),
    colour=(1.0, 0.8, 0.4),
    energy=1.5,
    range=200.0,
    falloff=2.0,        # 1.0=linear, 2.0=quadratic, 0.5=sqrt
)
self.add_child(light)

Directional Lights¶

DirectionalLight2D applies uniform lighting across the entire scene:

from simvx.core import DirectionalLight2D

sun = DirectionalLight2D(
    direction=(0.5, -1.0),   # Normalized automatically
    colour=(1.0, 1.0, 0.9),
    energy=0.8,
)
self.add_child(sun)

Shadow Occluders¶

LightOccluder2D casts shadows from light sources. Define a polygon in local coordinates:

from simvx.core import LightOccluder2D

wall = LightOccluder2D(
    polygon=((0, 0), (100, 0), (100, 20), (0, 20)),
    position=Vec2(200, 400),
)
self.add_child(wall)

Enable shadows on the light:

light.shadow_enabled = True
light.shadow_colour = (0, 0, 0, 0.8)  # Semi-transparent shadows

Light Properties¶

Property	Default	Description
`colour`	`(1, 1, 1)`	RGB, 0.0–1.0
`energy`	`1.0`	Intensity multiplier
`range`	`100.0`	Radius in pixels
`blend_mode`	`"add"`	`"add"` or `"mix"`
`enabled`	`True`	Toggle light on/off
`shadow_enabled`	`False`	Enable shadow casting
`shadow_colour`	`(0, 0, 0, 1)`	Shadow fill colour (RGBA)
`light_cull_mask`	`0xFFFFFFFF`	Bitmask for selective lighting

Example¶

See packages/graphics/examples/2d_light.py for a complete demo with multiple coloured lights and occluders.

API Reference¶

See simvx.core.light2d for the complete 2D lighting API.