SnowMeshDesc

The SnowMeshDesc class is a mesh descriptor that displays snow particle effects. It creates realistic snowfall effects using texture-based point sprites.

In addition to the properties below, the common properties from the base class (position, rotation, scale, matrix, matrixWorld, visible) are available. See MeshDesc for details.

Common Properties

position

Type: { x: number, y: number, z: number } | Vector3

Description: Specifies the center position of the snow particle effect in the ECEF coordinate system. You can convert from latitude/longitude using the geodeticToVector3 function.

Example:

import { geodeticToVector3, degreeToRadian, LLE } from "@navaramap/three";

const position = geodeticToVector3(
  new LLE(
    degreeToRadian(35.67564356091717),  // Latitude
    degreeToRadian(139.74511454748298), // Longitude
    10,                                  // Altitude
  ),
);

{
  position: position,
  snow: { ... }
}

visible

Type: boolean

Description: Controls the visibility of the object.

Default: true

Example:

{
  visible: false,
  snow: { ... }
}

Snow Properties

particleCount

Type: number

Description: Specifies the number of snowflake particles.

Default: 30000

Example:

{
  snow: {
    particleCount: 3000,
  }
}

radius

Type: number

Description: Specifies the distribution radius of the snow.

Default: 10

Example:

{
  snow: {
    radius: 15,
  }
}

areaWidth

Type: number

Description: Specifies the width of the snowfall area.

Default: 500

Example:

{
  snow: {
    areaWidth: 500,
  }
}

areaHeight

Type: number

Description: Specifies the height of the snowfall area.

Default: 1000

Example:

{
  snow: {
    areaHeight: 1000,
  }
}

speed

Type: number

Description: Specifies the falling speed of the snowflakes.

Default: 0.00005

Example:

{
  snow: {
    speed: 0.001,
  }
}

movementStrength

Type: { x: number, y: number, z: number }

Description: Specifies the strength of wind-driven movement of snowflakes for each axis.

Default: { x: 50, y: 20, z: 50 }

Example:

{
  snow: {
    movementStrength: { x: 0.5, y: 0, z: 0.5 },
  }
}

movementSpeed

Type: { x: number, y: number, z: number }

Description: Specifies the speed of wind-driven movement of snowflakes for each axis.

Default: { x: 0.0005, y: 0.0002, z: 0.0005 }

Example:

{
  snow: {
    movementSpeed: { x: 0.001, y: 0, z: 0.001 },
  }
}

size

Type: number

Description: Specifies the size of the snowflakes.

Default: 3

Example:

{
  snow: {
    size: 0.05,
  }
}

color

Type: number

Description: The color of the snowflakes.

Default: 0xffffff

Example:

import { Color } from "@navaramap/three";

{
  snow: {
    color: new Color().setStyle("#eeeeff").toHex(),
  }
}

opacity

Type: number

Description: Specifies the opacity of the snowflakes.

Default: 1

Example:

{
  snow: {
    opacity: 0.8,
  }
}

followCamera

Type: boolean

Description: Specifies whether the mesh follows the camera.

Default: true

Example:

{
  snow: {
    followCamera: true,
  }
}

maxHeight

Type: number

Description: Specifies the maximum altitude. Opacity decreases proportionally with camera altitude.

Default: 3000

Example:

{
  snow: {
    maxHeight: 5000,
  }
}

Usage Examples

Basic Usage

import ThreeView from "@navaramap/three";
import { SnowMeshDesc } from "@navaramap/three_default_descs";

const view = new ThreeView();
view.registerMesh("snow", SnowMeshDesc);
await view.init();

// Add a SnowMeshDesc
const snowDesc = view.addMesh<SnowMeshDesc>({
  snow: {
    particleCount: 3000,
    areaWidth: 500,
    areaHeight: 1000,
    speed: 0.001,
    movementStrength: { x: 0.3, y: 0, z: 0.3 },
    movementSpeed: { x: 0.0005, y: 0, z: 0.0005 },
    size: 0.05,
    opacity: 0.8,
    followCamera: true,
  },
});

Placing Snow at a Specific Location

import ThreeView, { Color, geodeticToVector3, degreeToRadian, LLE } from "@navaramap/three";
import { SnowMeshDesc } from "@navaramap/three_default_descs";

const view = new ThreeView({ animation: true });
view.registerMesh("snow", SnowMeshDesc);
await view.init();

// Calculate the position of Tokyo
const position = geodeticToVector3(
  new LLE(
    degreeToRadian(35.67564356091717),
    degreeToRadian(139.74511454748298),
    10,
  ),
);

// Add a SnowMeshDesc at a specific position
const snowDesc = view.addMesh<SnowMeshDesc>({
  visible: true,
  position: position,
  snow: {
    particleCount: 3000,
    speed: 0.001,
    color: new Color().setHex(0xffffff).toHex(),
    opacity: 0.8,
  },
});

// Toggle visibility
snowDesc.visible = false;