function calculateViewportUniforms()

in modules/core/src/shaderlib/project/viewport-uniforms.js [203:277]
57 lines of code
8 McCabe index (conditional complexity)

function calculateViewportUniforms({
  viewport,
  devicePixelRatio,
  coordinateSystem,
  coordinateOrigin
}) {
  const {
    projectionCenter,
    viewProjectionMatrix,
    cameraPosCommon,
    shaderCoordinateOrigin,
    geospatialOrigin
  } = calculateMatrixAndOffset(viewport, coordinateSystem, coordinateOrigin);

  // Calculate projection pixels per unit
  const distanceScales = viewport.getDistanceScales();

  const viewportSize = [viewport.width * devicePixelRatio, viewport.height * devicePixelRatio];

  const uniforms = {
    // Projection mode values
    project_uCoordinateSystem: coordinateSystem,
    project_uProjectionMode: viewport.projectionMode,
    project_uCoordinateOrigin: shaderCoordinateOrigin,
    project_uCenter: projectionCenter,
    project_uAntimeridian: (viewport.longitude || 0) - 180,

    // Screen size
    project_uViewportSize: viewportSize,
    project_uDevicePixelRatio: devicePixelRatio,

    // Distance at which screen pixels are projected
    project_uFocalDistance: viewport.focalDistance || 1,
    project_uCommonUnitsPerMeter: distanceScales.unitsPerMeter,
    project_uCommonUnitsPerWorldUnit: distanceScales.unitsPerMeter,
    project_uCommonUnitsPerWorldUnit2: DEFAULT_PIXELS_PER_UNIT2,
    project_uScale: viewport.scale, // This is the mercator scale (2 ** zoom)

    project_uViewProjectionMatrix: viewProjectionMatrix,

    // This is for lighting calculations
    project_uCameraPosition: cameraPosCommon
  };

  if (geospatialOrigin) {
    const distanceScalesAtOrigin = viewport.getDistanceScales(geospatialOrigin);
    switch (coordinateSystem) {
      case COORDINATE_SYSTEM.METER_OFFSETS:
        uniforms.project_uCommonUnitsPerWorldUnit = distanceScalesAtOrigin.unitsPerMeter;
        uniforms.project_uCommonUnitsPerWorldUnit2 = distanceScalesAtOrigin.unitsPerMeter2;
        break;

      case COORDINATE_SYSTEM.LNGLAT:
      case COORDINATE_SYSTEM.LNGLAT_OFFSETS:
        uniforms.project_uCommonUnitsPerWorldUnit = distanceScalesAtOrigin.unitsPerDegree;
        uniforms.project_uCommonUnitsPerWorldUnit2 = distanceScalesAtOrigin.unitsPerDegree2;
        break;

      // a.k.a "preprojected" positions
      case COORDINATE_SYSTEM.CARTESIAN:
        uniforms.project_uCommonUnitsPerWorldUnit = [1, 1, distanceScalesAtOrigin.unitsPerMeter[2]];
        uniforms.project_uCommonUnitsPerWorldUnit2 = [
          0,
          0,
          distanceScalesAtOrigin.unitsPerMeter2[2]
        ];
        break;

      default:
        break;
    }
  }

  return uniforms;
}