Particles

GPU based particle systems in A-Frame.

Particles are based on aframe-spe-particles-component, javascript loaded from aframe-spe-particles-component.min.js.

For now, it’s not directly supported, but rather by passing JSON inside the data{} element. The syntax for parameter names has been updated so instead of a name like this that is space-separated it becomes spaceSeparated (camel case). Three examples here have been created starting with the examples in aframe-spe-particles-component examples then reformulating to ARENA JSON syntax.

Particles are very complicated and take a lot of parameters. It would not make sense to translate all of them into explicit ARENA types, thus this flexible ‘raw JSON’ format is used.

Additional Python properties are available in the SpeParticles API Reference.

from arena import *

scene = Scene(host="arenaxr.org", scene="example")

position = Position(0, 0, -3)

@scene.run_once
def make_fire():
    sparks = Object(
        object_id="sparks",
        position=position,
        spe_particles=Particles(
            texture="static/images/textures/square.png",
            color=["yellow", "red"],
            particleCount=10,
            maxAge=0.5,
            maxAgeSpread=0.4,
            velocity=Position(0, 5, 0),
            velocitySpread=Position(0, 3, 0),
            wiggle=1,
            wiggleSpread=5,
            emitterScale=50,
            sizeSpread=[0.5],
            randomizeVelocity=True,
        )
    )
    scene.add_object(sparks)

    smoke = Object(
        object_id="smoke",
        position=position,
        spe_particles=Particles(
            texture="static/images/textures/fog.png",
            velocity=Position(0.4, 2, 0),
            velocitySpread=Position(1.4, 0, 1.4),
            particleCount=50,
            maxAge=4,
            size=[8, 16],
            opacity=[0, 1, 0],
            color=["#666", "#222"],
        )
    )
    scene.add_object(smoke)

    flames = Object(
        object_id="flames",
        position=position,
        spe_particles=Particles(
            texture="static/images/textures/explosion_sheet.png",
            textureFrames={"x": 5, "y": 5},
            velocity=Position(0.4, 0.1, 0),
            acceleration=Position(0, 2, 0),
            accelerationSpread=Position(0, 2, 0),
            velocitySpread=Position(0.4, 0, 0.4),
            particleCount=15,
            maxAge=1,
            size=[4, 8],
            sizeSpread=[2],
            opacity=[1, 0],
            wiggle=0,
            blending="additive",
        )
    )
    scene.add_object(flames)

scene.run_tasks()