/******************************************************************************
* Renders the plane in the viewports.
******************************************************************************/
Box3 SliceModifier::renderPlane(SceneRenderer* renderer, const Plane3& plane, const Box3& bb, const ColorA& color) const
{
// Compute intersection lines of slicing plane and bounding box.
QVector<Point3> vertices;
Point3 corners[8];
for(int i = 0; i < 8; i++)
corners[i] = bb[i];
planeQuadIntersection(corners, {{0, 1, 5, 4}}, plane, vertices);
planeQuadIntersection(corners, {{1, 3, 7, 5}}, plane, vertices);
planeQuadIntersection(corners, {{3, 2, 6, 7}}, plane, vertices);
planeQuadIntersection(corners, {{2, 0, 4, 6}}, plane, vertices);
planeQuadIntersection(corners, {{4, 5, 7, 6}}, plane, vertices);
planeQuadIntersection(corners, {{0, 2, 3, 1}}, plane, vertices);
// If there is not intersection with the simulation box then
// project the simulation box onto the plane.
if(vertices.empty()) {
const static int edges[12][2] = {
{0,1},{1,3},{3,2},{2,0},
{4,5},{5,7},{7,6},{6,4},
{0,4},{1,5},{3,7},{2,6}
};
for(int edge = 0; edge < 12; edge++) {
vertices.push_back(plane.projectPoint(corners[edges[edge][0]]));
vertices.push_back(plane.projectPoint(corners[edges[edge][1]]));
}
}
if(renderer) {
// Render plane-box intersection lines.
std::shared_ptr<LinePrimitive> buffer = renderer->createLinePrimitive();
buffer->setVertexCount(vertices.size());
buffer->setVertexPositions(vertices.constData());
buffer->setLineColor(color);
buffer->render(renderer);
}
// Compute bounding box.
Box3 vertexBoundingBox;
vertexBoundingBox.addPoints(vertices.constData(), vertices.size());
return vertexBoundingBox;
}
