MeshGeneratorCircularArc.h

#pragma once
 
#include "Foundation/Geometry/IndicesGenerator.h"
 
namespace {
  void circularArcFactory(Mesh* m, const ShapeDefinition& definition) {
    float angle;
    float end;
 
    if (definition.arcStart == definition.arcEnd) {
      angle = 0.0f;
      end = glm::pi<float>() * 2.0f;
    }
    else {
      angle = definition.arcStart;
      end = definition.arcEnd;
 
      if (end < angle) {
        end += glm::pi<float>() * 2.0f;
      }
    }
 
    assert(angle < end);
    assert(definition.refinement > 0);
 
    float                       stepSize = (end - angle) / definition.refinement;
    std::vector<PositionVertex> vertices;
    std::vector<uint32_t>       indices;
    size_t                      refinement = static_cast<size_t>(definition.refinement);
 
    vertices.reserve((refinement + 1) << 1);
 
    for ( ; angle <= end; angle += stepSize) {
      glm::vec3 v(std::cos(angle), std::sin(angle), 0.0f);
 
      vertices.push_back({v * definition.size.x});
      vertices.push_back({v * definition.size.y});
    }
 
    Cogs::Geometry::generateQuadIndices(indices, definition.refinement, 0, true);
 
    m->setVertexData(vertices.data(), vertices.size());
    m->setIndexData(indices.data(), indices.size());
    m->setBounds(computeBoundingBoxFromVertexFormat(vertices.begin(), vertices.end()));
  }
}