MouseCameraAxisRotateManipulator

Source

index.js

import { vec3, mat4 } from 'gl-matrix';
import macro from 'vtk.js/Sources/macros';
import vtkCompositeCameraManipulator from 'vtk.js/Sources/Interaction/Manipulators/CompositeCameraManipulator';
import vtkCompositeMouseManipulator from 'vtk.js/Sources/Interaction/Manipulators/CompositeMouseManipulator';
import * as vtkMath from 'vtk.js/Sources/Common/Core/Math';
import vtkMatrixBuilder from 'vtk.js/Sources/Common/Core/MatrixBuilder';

// ----------------------------------------------------------------------------
// vtkMouseCameraAxisRotateManipulator methods
// ----------------------------------------------------------------------------

function vtkMouseCameraAxisRotateManipulator(publicAPI, model) {
  // Set our className
  model.classHierarchy.push('vtkMouseCameraAxisRotateManipulator');

  const newCamPos = new Float64Array(3);
  const newFp = new Float64Array(3);
  // const newViewUp = new Float64Array(3);
  const trans = new Float64Array(16);
  const v2 = new Float64Array(3);
  const centerNeg = new Float64Array(3);
  const direction = new Float64Array(3);
  const fpDirection = new Float64Array(3);

  publicAPI.onButtonDown = (interactor, renderer, position) => {
    model.previousPosition = position;
  };

  publicAPI.onMouseMove = (interactor, renderer, position) => {
    if (!position) {
      return;
    }

    const camera = renderer.getActiveCamera();
    const cameraPos = camera.getPosition();
    const cameraFp = camera.getFocalPoint();
    const cameraViewUp = camera.getViewUp();
    const cameraDirection = camera.getDirectionOfProjection();

    mat4.identity(trans);

    const { center, rotationFactor, rotationAxis } = model;

    // Translate to center
    mat4.translate(trans, trans, center);

    const dx = model.previousPosition.x - position.x;
    const dy = model.previousPosition.y - position.y;

    const size = interactor.getView().getSize();

    // Azimuth
    mat4.rotate(
      trans,
      trans,
      vtkMath.radiansFromDegrees(((360.0 * dx) / size[0]) * rotationFactor),
      rotationAxis
    );

    // Elevation
    vtkMath.cross(cameraDirection, cameraViewUp, v2);
    mat4.rotate(
      trans,
      trans,
      vtkMath.radiansFromDegrees(((-360.0 * dy) / size[1]) * rotationFactor),
      v2
    );

    // Translate back
    centerNeg[0] = -center[0];
    centerNeg[1] = -center[1];
    centerNeg[2] = -center[2];
    mat4.translate(trans, trans, centerNeg);

    // Apply transformation to camera position, focal point, and view up
    vec3.transformMat4(newCamPos, cameraPos, trans);
    vec3.transformMat4(newFp, cameraFp, trans);

    // what is the current direction from the fp
    // to the camera
    vec3.subtract(fpDirection, newCamPos, newFp);
    vec3.normalize(fpDirection, fpDirection);

    // make the top sticky to avoid accidental flips
    if (Math.abs(vec3.dot(fpDirection, rotationAxis)) > 0.95) {
      // this can be smarter where it still allows Azimuth here
      // but prevents the elevation part
      model.previousPosition = position;
      return;
    }

    if (model.useHalfAxis) {
      // what is the current distance from pos to center of rotation
      const distance = vec3.distance(newCamPos, center);

      // what is the current direction from the center of rotation
      // to the camera
      vec3.subtract(direction, newCamPos, center);
      vec3.normalize(direction, direction);

      // project the rotation axis onto the direction
      // so we know how much below the half plane we are
      const dotP = vec3.dot(rotationAxis, direction);

      if (dotP < 0) {
        // adjust the new camera position to bring it up to the half plane
        vec3.scaleAndAdd(newCamPos, newCamPos, rotationAxis, -dotP * distance);

        // the above step will change the distance which might feel odd
        // so the next couple lines restore the distance to the center

        // what is the new direction from the center of rotation
        // to the camera
        vec3.subtract(direction, newCamPos, center);
        vec3.normalize(direction, direction);
        vec3.scaleAndAdd(newCamPos, center, direction, distance);

        // compute original cam direction to center
        vec3.subtract(v2, cameraPos, center);
        vec3.normalize(v2, v2);

        // const rAngle = 0.0;
        const acosR = Math.min(1.0, Math.max(-1.0, vec3.dot(direction, v2)));
        const rAngle = Math.acos(acosR); // 0 to pi
        vec3.cross(v2, v2, direction);
        vec3.normalize(v2, v2);

        vec3.subtract(newFp, cameraFp, center);
        const fpDist = vec3.length(newFp);

        // Note it normalizes the vector to be rotated
        const result = [...newFp];
        vtkMatrixBuilder.buildFromRadian().rotate(rAngle, v2).apply(result);
        vec3.scaleAndAdd(newFp, center, result, fpDist);
      }
    }

    camera.setPosition(newCamPos[0], newCamPos[1], newCamPos[2]);
    camera.setFocalPoint(newFp[0], newFp[1], newFp[2]);
    camera.setViewUp(rotationAxis);

    renderer.resetCameraClippingRange();

    if (interactor.getLightFollowCamera()) {
      renderer.updateLightsGeometryToFollowCamera();
    }

    model.previousPosition = position;
  };
}

// ----------------------------------------------------------------------------
// Object factory
// ----------------------------------------------------------------------------

const DEFAULT_VALUES = {
  rotationAxis: [0, 0, 1],
  useHalfAxis: true,
};

// ----------------------------------------------------------------------------

export function extend(publicAPI, model, initialValues = {}) {
  Object.assign(model, DEFAULT_VALUES, initialValues);

  // Inheritance
  macro.obj(publicAPI, model);
  macro.setGet(publicAPI, model, ['rotationAxis', 'useHalfAxis']);
  vtkCompositeMouseManipulator.extend(publicAPI, model, initialValues);
  vtkCompositeCameraManipulator.extend(publicAPI, model, initialValues);

  // Object specific methods
  vtkMouseCameraAxisRotateManipulator(publicAPI, model);
}

// ----------------------------------------------------------------------------

export const newInstance = macro.newInstance(
  extend,
  'vtkMouseCameraAxisRotateManipulator'
);

// ----------------------------------------------------------------------------

export default { newInstance, extend };