LightSystemPlugin

Create the global light system plugin

Baseline color applied to unlit areas of the scene. Defaults to BLACK (pitch dark). Set to a small RGB for a faint ambient. The lightmap is cleared to this color each frame, then lights add on top, then the result multiplies the scene.

The background map, objects with castBackgroundShadow drawn black on white, the shadow map's size and place, made by a directional light when something casts into it and kept while the light is, read only

Shader for compositing the lightmap over the main scene

Vertex array object for the composite shader

The scene's directional light, a sun, or undefined, read only

The directional light as built this frame, white where it reaches, over the shadow map's area, read only

Pixels across the square textures a directional light is built in, covering the shadow map's area; larger is sharper and slower; a power of two, as shadowMapSize, so their texels line up

True while emissive objects draw into the lightmap, read only, see EngineObject.emissive

When false, the render pass is skipped entirely

Shader for drawing per-Light falloff blobs into the lightmap

Vertex array object for the light shader

Where Canvas2D draws go during the shadow and emissive passes, a 1x1 canvas, so text in a render() is not drawn twice

Copies the shadow map around a light into its texture

Vertex array object for the copy shader

The shadow map, casters drawn black on white around the camera, read only

World position of the shadow map's bottom left corner, set each shadow pass

How many times the larger side of the view the shadow map covers, so casters just off screen still cast in; raise it when lights reach further than a view past the screen

Pixels across the square shadow map, made again when changed

World size the shadow map covers, set each shadow pass

True while the shadow pass runs, read only, so a render() can skip parts that should not cast

Stretch passes per shadow casting light, fewer is cheaper and shorter shadows

Cast shadows: every object draws black into a shadow map once a frame and each light's rays stop at them; off by default and free when off

How much light bleeds into a caster's near side, 0 for hard edged casters, 1 for most; the bleed reaches further in under a bigger light, so a thin wall under a big one lets some through, lower it for those

One stretch pass of a light's shadow texture

Vertex array object for the stretch shader

One of the two textures each light's shadow is built in

The other

Pixels across each light's own shadow texture, made again when changed; larger is sharper, and a gap between casters narrower than about 4*radius/shadowTextureSize world units closes

The lightmap texture

Size of the lightmap texture, follows mainCanvasSize (css pixels, so it is not scaled by canvasPixelRatio) unless a size was passed

True when no size was passed, so the lightmap follows mainCanvasSize

Bring the sizes of the textures it makes down to what the device can make: shadowMapSize, shadowTextureSize and a textureSize given by hand; called before they are made, so a size too big falls back instead of failing

Draw a single Light's falloff blob into the currently bound lightmap. Called by Light.renderLight() during the plugin's render pass.

Build a light's shadow texture from the shadow map: the map around the light, its casters stretched away from the light a little further each pass with light bled into their near sides. Leaves the result on texture unit 1 and the lightmap bound again. Called by drawLight.

In the shadow pass, let the draws that follow keep their color in the shadow map, so light passing through them is tinted instead of blocked: a stained glass window, colored smoke. Any draw blocks light by its alpha, so a fading sprite casts a fading shadow; this keeps the color as well. It covers what was drawn under it in the map as any draw does, so glass drawn after a wall cuts a tinted window in the wall's shadow, and a wall drawn after the glass covers it. Does nothing outside the pass, so a render() can call it around those draws unconditionally; set it back to false after them.