Hoops_Exchange/exchange/exchangesource/MeshViewer/model/he/representation_item.cpp

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 *
 * Copyright (c) 2010 - 2025 by Tech Soft 3D, Inc.
 * The information contained herein is confidential and proprietary to Tech Soft 3D, Inc., and considered a trade secret
 * as defined under civil and criminal statutes. Tech Soft 3D shall pursue its civil and criminal remedies in the event
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#include <map>
#include "representation_item.h"
#include "../../utils/properties.h"
#include "../../utils/bounding_box.h"
#include "../../utils/geometry.h"
#include "../../model/exchange.h"

namespace he
{
	namespace geometry
	{

		RepresentationItem::RepresentationItem(A3DRiRepresentationItem* rep_item, const A3DMiscCascadedAttributes* cascaded_attributes) :
			Entity()
		{
			A3D_INITIALIZE_DATA(A3DMeshData, mesh_data);
			// for each representation item list, we compute a mesh based on triangle only.
			status = A3DRiComputeMesh(rep_item, cascaded_attributes, &mesh_data, nullptr);
			if (status != A3D_SUCCESS)
			{
				A3DRWParamsTessellationData tess_params;
				A3D_INITIALIZE_DATA(A3DRWParamsTessellationData, tess_params);
				tess_params.m_eTessellationLevelOfDetail = kA3DTessLODMedium;
				A3DRiRepresentationItemComputeTessellation(rep_item, &tess_params);
				status = A3DRiComputeMesh(rep_item, cascaded_attributes, &mesh_data, nullptr);
			}
		}

		RepresentationItem::~RepresentationItem()
		{
			A3DRiComputeMesh(nullptr, nullptr, &mesh_data, nullptr);
		}

		bool RepresentationItem::is_unicolor() const
		{
			return mesh_data.m_puiStyleIndexPerFace == nullptr;
		}



		void RepresentationItem::prepare_render_buffer(std::vector <utils::geometry::BufferData>& buffer_data_array)
		{
			if (is_unicolor())
			{
				utils::geometry::BufferData buffer_data;
				build_one_buffer(buffer_data);
				buffer_data_array.push_back(buffer_data);
			}
			else
			{
				build_buffer_per_style(buffer_data_array);
			}

		}

		void RepresentationItem::build_one_buffer(utils::geometry::BufferData& buffer_data) const
		{
			buffer_data.vertices.reserve(mesh_data.m_uiCoordSize / 3);

			// For each mesh, we create model buffer, and store graphical information, and all positions
			// associated to it.
			for (A3DUns32 vertex_i = 0; vertex_i < mesh_data.m_uiCoordSize; vertex_i+=3)
			{
				utils::geometry::Vertex vertex;
				vertex.position = glm::vec3(mesh_data.m_pdCoords[vertex_i],
					mesh_data.m_pdCoords[vertex_i + 1],
					mesh_data.m_pdCoords[vertex_i + 2]);
				vertex.normal = glm::vec3(mesh_data.m_pdNormals[vertex_i],
					mesh_data.m_pdNormals[vertex_i + 1],
					mesh_data.m_pdNormals[vertex_i + 2]);

				buffer_data.mesh_box.add_point(vertex.position);
				buffer_data.vertices.push_back(vertex);
			}

			// Count the total number of indices
			size_t indiceCount = 0;
			for (A3DUns32 face_i = 0; face_i < mesh_data.m_uiFaceSize; ++face_i) {
				indiceCount += mesh_data.m_puiTriangleCountPerFace[face_i];
			}
			indiceCount *= 3; // 3 indices per triangle
			buffer_data.indices.reserve(indiceCount);

			for (A3DUns32 vertex_i = 0; vertex_i < indiceCount; vertex_i++)
				buffer_data.indices.push_back(mesh_data.m_puiVertexIndicesPerFace[vertex_i]);

			buffer_data.graphics = model::exchange::convert_style(mesh_data.m_uiStyleIndex);
		}

		void RepresentationItem::build_buffer_per_style(std::vector <utils::geometry::BufferData>& buffers_data) const
		{
			int idx = 0;

			 // sort face by style, and create one buffer data per style

			std::map<A3DUns32, std::vector<A3DUns32>> style_face_indices;
			std::vector<std::vector<A3DUns32>> vertex_indices_per_face(mesh_data.m_uiFaceSize);
			A3DUns32 vertex_index = 0;

			for (A3DUns32 f = 0; f < mesh_data.m_uiFaceSize; f++)
			{
				const A3DUns32 triangle_count = mesh_data.m_puiTriangleCountPerFace[f];
				if (triangle_count == 0)
					continue;
				A3DUns32 face_style = mesh_data.m_puiStyleIndexPerFace[f];
				style_face_indices[face_style].push_back(f);

				// Store vertex indices per face
				const A3DUns32 start_index = vertex_index;
				const A3DUns32 end_index = vertex_index + (triangle_count * 3);
				for (A3DUns32 v = start_index; v < end_index; ++v)
				{
					vertex_indices_per_face[f].push_back(mesh_data.m_puiVertexIndicesPerFace[v]);
				}
				vertex_index = end_index;
			}

			// for each mesh, we create OnpenGL model (buffer), and store graphical information, and all positions
			// associated to it.

			for (auto iter = style_face_indices.begin(); iter != style_face_indices.end(); ++iter)
			{
				utils::geometry::BufferData buffer_data;
				buffer_data.graphics = model::exchange::convert_style(iter->first);

				idx = 0;
				for (auto& f : iter->second)
				{
					// for each face
					A3DUns32 triangle_count = mesh_data.m_puiTriangleCountPerFace[f];
					const std::vector<A3DUns32>& vertex_indices = vertex_indices_per_face[f];

					std::vector<utils::geometry::Vertex> vertices;
					utils::geometry::BoundingBox box;
					utils::geometry::Vertex vertex;
					for (A3DUns32 t = 0; t < triangle_count; t++)
					{
						// for each triangle
						for (A3DUns32 v = 0; v < 3; v++)
						{
							const uint32_t indice = vertex_indices[t * 3 + v] * 3;
							vertex.position = glm::vec3(mesh_data.m_pdCoords[indice],
								mesh_data.m_pdCoords[indice + 1],
								mesh_data.m_pdCoords[indice + 2]);
							vertex.normal = glm::vec3(mesh_data.m_pdNormals[indice],
								mesh_data.m_pdNormals[indice + 1],
								mesh_data.m_pdNormals[indice + 2]);

							buffer_data.mesh_box.add_point(vertex.position);
							buffer_data.vertices.push_back(vertex);
							buffer_data.indices.push_back(idx++);
						}
					}
				}
				buffers_data.push_back(buffer_data);
			}
		}

	}
}