@kitware/vtk.js/Interaction/Manipulators/MouseCameraTrackballPanManipulatorAutoCenter.js

Visualization Toolkit for the Web

import { m as macro } from '../../macros2.js';
import vtkMouseCameraTrackballPanManipulator from './MouseCameraTrackballPanManipulator.js';
import { mat4, vec3 } from 'gl-matrix';

// ----------------------------------------------------------------------------
// Helper functions for center of rotation adjustment
// ----------------------------------------------------------------------------

/**
 * Transforms a vector by the transformation delta between two matrices.
 *
 * @param {Object} tempObjects - Temporary matrices/vectors for computation
 * @param {mat4} beforeMatrix - Matrix before transformation
 * @param {mat4} afterMatrix - Matrix after transformation
 * @param {Array} vector - Vector to transform [x, y, z]
 * @returns {Array} Transformed vector [x, y, z]
 */
function transformVectorByTransformation(tempObjects, beforeMatrix, afterMatrix, vector) {
  const {
    matrixA,
    matrixB,
    newCenter
  } = tempObjects;

  // The view matrix from vtk.js is row-major, but gl-matrix expects column-major.
  // We need to transpose them before use.
  mat4.transpose(matrixA, beforeMatrix);
  mat4.transpose(matrixB, afterMatrix);
  mat4.invert(matrixB, matrixB);

  // Compute delta transformation matrix
  mat4.multiply(matrixA, matrixB, matrixA);
  vec3.transformMat4(newCenter, vector, matrixA);
  return newCenter;
}

/**
 * Computes the new center of rotation based on camera movement.
 * When the camera moves (pan), the center of rotation should move
 * by the same transformation.
 *
 * @param {Object} tempObjects - Temporary matrices/vectors for computation
 * @param {Object} renderer - VTK renderer
 * @param {mat4} beforeCameraMatrix - Camera view matrix before movement
 * @param {Array} oldCenterOfRotation - Previous center of rotation [x, y, z]
 * @returns {Array} New center of rotation [x, y, z]
 */
function computeNewCenterOfRotation(tempObjects, renderer, beforeCameraMatrix, oldCenterOfRotation) {
  const cam = renderer.getActiveCamera();
  if (!cam || !beforeCameraMatrix) {
    return oldCenterOfRotation;
  }
  const afterMatrixRowMajor = cam.getViewMatrix();
  return transformVectorByTransformation(tempObjects, beforeCameraMatrix, afterMatrixRowMajor, oldCenterOfRotation);
}
function getCameraMatrix(renderer, tempMatrix) {
  const cam = renderer.getActiveCamera();
  if (cam) {
    mat4.copy(tempMatrix, cam.getViewMatrix());
    return tempMatrix;
  }
  return null;
}
function vtkMouseCameraTrackballPanManipulatorAutoCenter(publicAPI, model) {
  model.classHierarchy.push('vtkMouseCameraTrackballPanManipulatorAutoCenter');
  const tempCameraMatrix = mat4.create();
  const tempComputeObjects = {
    matrixA: mat4.create(),
    matrixB: mat4.create(),
    newCenter: vec3.create()
  };
  const superOnMouseMove = publicAPI.onMouseMove;
  publicAPI.onMouseMove = (interactor, renderer, position) => {
    if (!position) {
      return;
    }
    const beforeCameraMatrix = getCameraMatrix(renderer, tempCameraMatrix);
    superOnMouseMove(interactor, renderer, position);
    if (beforeCameraMatrix && model.center) {
      const newCenter = computeNewCenterOfRotation(tempComputeObjects, renderer, beforeCameraMatrix, model.center);
      publicAPI.setCenter(newCenter);
      const style = interactor.getInteractorStyle();
      if (style && style.setCenterOfRotation) {
        style.setCenterOfRotation(newCenter);
      }
    }
  };
}

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

const DEFAULT_VALUES = {};

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

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

  // Inheritance
  vtkMouseCameraTrackballPanManipulator.extend(publicAPI, model, initialValues);

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

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

const newInstance = macro.newInstance(extend, 'vtkMouseCameraTrackballPanManipulatorAutoCenter');

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

var index = {
  newInstance,
  extend
};

export { index as default, extend, newInstance };