InfiniteGridHelper constructor

InfiniteGridHelper({ double? size1, double? size2, Color? color, double? distance, RotationOrders axes = RotationOrders.xyz, })

size1 - Dimensions of the inner grid. By default, it is 10.

size2 - Dimensions of the outer grid. By default, it is 100.

Color - A hexadecimal value and an CSS-Color name. Default is 0x444444

distance - It is the distance from the camera at which the grid starts to disappear. This helps create a smooth fading effect. By default it is 8000.

axes - Axes directions along which the grid will be constructed. By default, it is ‘xzy’.

Implementation

factory InfiniteGridHelper({
  double? size1,
  double? size2,
  Color? color,
  double? distance,
  RotationOrders axes = RotationOrders.xyz
}) {
  color = color ?? Color.fromHex32(0x444444);
  size1 = size1 ?? 10;
  size2 = size2 ?? 100;
  distance = distance ?? 8000;

  String planeAxes = axes.name.substring(0, 2);

  PlaneGeometry geometry = PlaneGeometry(2, 2, 1, 1);

  final vertexShader = '''
  varying vec3 worldPosition;
  uniform float uDistance;

  void main() {
      vec3 pos = position.${axes.name} * uDistance;
      pos.$planeAxes += cameraPosition.$planeAxes;

      worldPosition = pos;
      gl_Position = projectionMatrix * modelViewMatrix * vec4(pos, 1.0);
  }
  ''';

  final fragmentShader = '''
   varying vec3 worldPosition;

   uniform float uSize1;
   uniform float uSize2;
   uniform vec3 uColor;
   uniform float uDistance;

      float getGrid(float size) {
          vec2 r = worldPosition.$planeAxes / size;

          vec2 grid = abs(fract(r - 0.5) - 0.5) / fwidth(r);
          float line = min(grid.x, grid.y);

          return 1.0 - min(line, 1.0);
      }

      void main() {
          float d = 1.0 - min(distance(cameraPosition.$planeAxes, worldPosition.$planeAxes) / uDistance, 1.0);

          float g1 = getGrid(uSize1);
          float g2 = getGrid(uSize2);

          gl_FragColor = vec4(uColor.rgb, mix(g2, g1, g1) * pow(d, 3.0));
          gl_FragColor.a = mix(0.5 * gl_FragColor.a, gl_FragColor.a, g2);

          if ( gl_FragColor.a <= 0.0 ) discard;
      }
  ''';

  final material = ShaderMaterial.fromMap({
    'side': DoubleSide,
    'uniforms': {
      'uSize1': {'value': size1},
      'uSize2': {'value': size2},
      'uColor': {'value': color},
      'uDistance': {'value': distance}
    },
    'transparent': true,
    'extensions': {
      'derivatives': {'value': true}
    },
    'vertexShader': vertexShader,
    'fragmentShader': fragmentShader
  });

  return InfiniteGridHelper.create(geometry, material);
}