feat(polydatacellnormals): programatically choose to compute cell nor…

…mals

closes Kitware#2434

Sources/Filters/Core/PolyDataNormals/example/index.js

@@ -0,0 +1,94 @@
+import 'vtk.js/Sources/favicon';
+
+// Load the rendering pieces we want to use (for both WebGL and WebGPU)
+import 'vtk.js/Sources/Rendering/Profiles/Geometry';
+
+import vtkFullScreenRenderWindow from 'vtk.js/Sources/Rendering/Misc/FullScreenRenderWindow';
+import vtkActor from 'vtk.js/Sources/Rendering/Core/Actor';
+import vtkMapper from 'vtk.js/Sources/Rendering/Core/Mapper';
+import vtkLineSource from 'vtk.js/Sources/Filters/Sources/LineSource';
+import vtkSphereSource from 'vtk.js/Sources/Filters/Sources/SphereSource';
+
+import vtkPolyDataNormals from 'vtk.js/Sources/Filters/Core/PolyDataNormals';
+
+// ----------------------------------------------------------------------------
+// Standard rendering code setup
+// ----------------------------------------------------------------------------
+
+const fullScreenRenderer = vtkFullScreenRenderWindow.newInstance();
+const renderer = fullScreenRenderer.getRenderer();
+const renderWindow = fullScreenRenderer.getRenderWindow();
+
+const computeNormals = vtkPolyDataNormals.newInstance();
+
+const sphere = vtkSphereSource.newInstance({
+  thetaResolution: 4,
+  phiResolution: 4,
+});
+const polydata = sphere.getOutputData();
+
+const mapper = vtkMapper.newInstance();
+const actor = vtkActor.newInstance();
+
+actor.setMapper(mapper);
+mapper.setInputData(polydata);
+
+renderer.addActor(actor);
+
+computeNormals.setInputData(polydata);
+computeNormals.setComputeCellNormals(true);
+computeNormals.update();
+
+const cellNormals = computeNormals.getOutputData().getCellData().getNormals();
+
+const pointsData = polydata.getPoints().getData();
+const polysData = polydata.getPolys().getData();
+
+let numberOfPoints = 0;
+const cellPointIds = [0, 0, 0];
+let normalId = 0;
+
+for (let c = 0; c < polysData.length; c += numberOfPoints + 1) {
+  numberOfPoints = polysData[c];
+
+  if (numberOfPoints < 3) {
+        continue; // eslint-disable-line
+  }
+
+  for (let i = 1; i <= 3; ++i) {
+    cellPointIds[i - 1] = 3 * polysData[c + i];
+  }
+
+  const v1 = pointsData.slice(cellPointIds[0], cellPointIds[0] + 3);
+  const v2 = pointsData.slice(cellPointIds[1], cellPointIds[1] + 3);
+  const v3 = pointsData.slice(cellPointIds[2], cellPointIds[2] + 3);
+
+  const center = [
+    (v1[0] + v2[0] + v3[0]) / 3,
+    (v1[1] + v2[1] + v3[1]) / 3,
+    (v1[2] + v2[2] + v3[2]) / 3,
+  ];
+
+  const line = vtkLineSource.newInstance({
+    point1: center,
+    point2: [
+      center[0] + cellNormals[normalId++],
+      center[1] + cellNormals[normalId++],
+      center[2] + cellNormals[normalId++],
+    ],
+  });
+
+  const lineMapper = vtkMapper.newInstance();
+  const lineActor = vtkActor.newInstance();
+
+  lineActor.setMapper(lineMapper);
+  lineMapper.setInputData(line.getOutputData());
+  renderer.addActor(lineActor);
+}
+
+// Display the resulting STL
+renderer.resetCamera();
+renderWindow.render();
+
+global.renderer = renderer;
+global.renderWindow = renderWindow;

Sources/Filters/Core/PolyDataNormals/index.js

@@ -5,6 +5,11 @@ import vtkMath from 'vtk.js/Sources/Common/Core/Math/index';
 import vtkPolyData from 'vtk.js/Sources/Common/DataModel/PolyData';
 import vtkTriangle from 'vtk.js/Sources/Common/DataModel/Triangle';
 
+export const NormalType = {
+  CELL: 'cell',
+  POINT: ' point',
+};
+
 // ----------------------------------------------------------------------------
 // vtkPolyDataNormals methods
 // ----------------------------------------------------------------------------
@@ -69,6 +74,49 @@ function vtkPolyDataNormals(publicAPI, model) {
     return normalsData;
   };
 
+  publicAPI.vtkPolyDataCellNormalsExecute = (polyData) => {
+    const pointsData = polyData.getPoints().getData();
+    const polysData = polyData.getPolys().getData();
+    const numPolys = polyData.getPolys().getNumberOfCells();
+
+    if (!pointsData || !polysData) {
+      return null;
+    }
+
+    const normalsData = new Float32Array(numPolys * 3);
+
+    let normalsIndex = 0;
+    let numberOfPoints = 0;
+    const cellPointIds = [0, 0, 0];
+
+    for (let c = 0; c < polysData.length; c += numberOfPoints + 1) {
+      numberOfPoints = polysData[c];
+
+      if (numberOfPoints < 3) {
+        continue; // eslint-disable-line
+      }
+
+      for (let i = 1; i <= 3; ++i) {
+        cellPointIds[i - 1] = 3 * polysData[c + i];
+      }
+
+      const cellNormal = [];
+
+      vtkTriangle.computeNormal(
+        pointsData.slice(cellPointIds[0], cellPointIds[0] + 3),
+        pointsData.slice(cellPointIds[1], cellPointIds[1] + 3),
+        pointsData.slice(cellPointIds[2], cellPointIds[2] + 3),
+        cellNormal
+      );
+
+      normalsData[normalsIndex++] = cellNormal[0];
+      normalsData[normalsIndex++] = cellNormal[1];
+      normalsData[normalsIndex++] = cellNormal[2];
+    }
+
+    return normalsData;
+  };
+
   publicAPI.requestData = (inData, outData) => {
     const numberOfInputs = publicAPI.getNumberOfInputPorts();
 
@@ -105,6 +153,13 @@ function vtkPolyDataNormals(publicAPI, model) {
 
     output.getPointData().setNormals(outputNormals);
 
+    if (model.computeCellNormals) {
+      const outputCellNormalsData =
+        publicAPI.vtkPolyDataCellNormalsExecute(input);
+
+      output.getCellData().setNormals(outputCellNormalsData);
+    }
+
     outData[0] = output;
   };
 }
@@ -130,6 +185,8 @@ export function extend(publicAPI, model, initialValues = {}) {
 
   macro.algo(publicAPI, model, 1, 1);
 
+  macro.setGet(publicAPI, model, ['computeCellNormals']);
+
   /* Object specific methods */
 
   vtkPolyDataNormals(publicAPI, model);