CAssimpModel.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

// This file contains portions of code from Assimp's example:
// "Sample_SimpleOpenGL.c"

#include "opengl-precomp.h"  // Precompiled header

#include <mrpt/opengl/CAssimpModel.h>

#if MRPT_HAS_ASSIMP
#if defined(MRPT_ASSIMP_VERSION_MAJOR) && MRPT_ASSIMP_VERSION_MAJOR < 3
#include <aiPostProcess.h>
#include <aiScene.h>
#include <assimp.h>
#else
#include <assimp/cimport.h>
#include <assimp/postprocess.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/LogStream.hpp>
#endif
#endif

#include <mrpt/serialization/CArchive.h>
#include <mrpt/system/filesystem.h>

using namespace mrpt;
using namespace mrpt::opengl;
using namespace mrpt::math;
using namespace std;
using mrpt::img::CImage;

IMPLEMENTS_SERIALIZABLE(CAssimpModel, CRenderizable, mrpt::opengl)

struct RenderElements
{
    std::vector<mrpt::math::TPoint3Df>* lines_vbd = nullptr;
    std::vector<mrpt::img::TColor>* lines_cbd = nullptr;
    std::vector<mrpt::math::TPoint3Df>* pts_vbd = nullptr;
    std::vector<mrpt::img::TColor>* pts_cbd = nullptr;
    std::vector<mrpt::opengl::TTriangle>* tris = nullptr;
};

#if MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP
// Note: Look at older git versions to see pre-OpenGL3 version with more texture
// supports, etc. load_textures(), etc.
static void recursive_render(
    const aiScene* sc, const aiNode* nd, const mrpt::poses::CPose3D& transf,
    RenderElements& re);

// Just return the diffuse color:
static mrpt::img::TColor apply_material(const aiMaterial* mtl);
static void get_bounding_box(
    const aiScene* sc, aiVector3D* min, aiVector3D* max);
static void get_bounding_box_for_node(
    const aiScene* sc, const aiNode* nd, aiVector3D* min, aiVector3D* max,
    aiMatrix4x4* trafo);
#endif  // MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP

void CAssimpModel::render(const RenderContext& rc) const
{
    switch (rc.shader_id)
    {
        case DefaultShaderID::POINTS:
            CRenderizableShaderPoints::render(rc);
            break;
        case DefaultShaderID::TRIANGLES:
            CRenderizableShaderTriangles::render(rc);
            break;
        case DefaultShaderID::WIREFRAME:
            CRenderizableShaderWireFrame::render(rc);
            break;
    };
}
void CAssimpModel::renderUpdateBuffers() const
{
    // Process all elements at once:
    const_cast<CAssimpModel&>(*this).onUpdateBuffers_all();

    CRenderizableShaderPoints::renderUpdateBuffers();
    CRenderizableShaderTriangles::renderUpdateBuffers();
    CRenderizableShaderWireFrame::renderUpdateBuffers();
}

// special case for assimp: update all buffers within one run over the scene
// structure.
void CAssimpModel::onUpdateBuffers_all()
{
    auto& lines_vbd = CRenderizableShaderWireFrame::m_vertex_buffer_data;
    auto& lines_cbd = CRenderizableShaderWireFrame::m_color_buffer_data;
    lines_vbd.clear();
    lines_cbd.clear();

    auto& pts_vbd = CRenderizableShaderPoints::m_vertex_buffer_data;
    auto& pts_cbd = CRenderizableShaderPoints::m_color_buffer_data;
    pts_vbd.clear();
    pts_cbd.clear();

    auto& tris = CRenderizableShaderTriangles::m_triangles;
    tris.clear();

    if (!m_assimp_scene->scene) return;  // No scene

    RenderElements re;
    re.lines_vbd = &lines_vbd;
    re.lines_cbd = &lines_cbd;
    re.pts_vbd = &pts_vbd;
    re.pts_cbd = &pts_cbd;
    re.tris = &tris;

#if MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP
    auto* scene = reinterpret_cast<aiScene*>(m_assimp_scene->scene);

    const auto transf = mrpt::poses::CPose3D();

    recursive_render(scene, scene->mRootNode, transf, re);
#endif
}

// These 3: already done in onUpdateBuffers_all()
void CAssimpModel::onUpdateBuffers_Wireframe() {}
void CAssimpModel::onUpdateBuffers_Points() {}
void CAssimpModel::onUpdateBuffers_Triangles() {}

uint8_t CAssimpModel::serializeGetVersion() const { return 0; }
void CAssimpModel::serializeTo(mrpt::serialization::CArchive& out) const
{
    writeToStreamRender(out);

    const bool empty = m_assimp_scene->scene != nullptr;
    out << empty;

    if (!empty)
    {
#if MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP
        // aiScene *scene = (aiScene *) m_assimp_scene->scene;
        THROW_EXCEPTION("MRPT can't serialize Assimp objects yet!");
#else
        THROW_EXCEPTION("MRPT compiled without OpenGL and/or Assimp");
#endif
    }
}

void CAssimpModel::serializeFrom(
    mrpt::serialization::CArchive& in, uint8_t version)
{
    THROW_EXCEPTION("MRPT can't serialize Assimp objects yet!");

    switch (version)
    {
        case 0:
        {
            readFromStreamRender(in);

            clear();
        }
        break;
        default:
            MRPT_THROW_UNKNOWN_SERIALIZATION_VERSION(version);
    };
    CRenderizable::notifyChange();
}

CAssimpModel::CAssimpModel() : m_bbox_min(0, 0, 0), m_bbox_max(0, 0, 0)
{
    m_assimp_scene = std::make_shared<TImplAssimp>();
}

CAssimpModel::~CAssimpModel() { clear(); }
/*---------------------------------------------------------------
                            clear
  ---------------------------------------------------------------*/
void CAssimpModel::clear()
{
    CRenderizable::notifyChange();
    m_assimp_scene = std::make_shared<TImplAssimp>();
    m_modelPath.clear();
    // m_textures_loaded = false;

#if MRPT_HAS_OPENGL_GLUT
#if 0
    if (!m_textureIds.empty())
    {
        glDeleteTextures(m_textureIds.size(), &m_textureIds[0]);
        m_textureIds.clear();
    }
    m_textureIdMap.clear();
#endif
#endif
}

void CAssimpModel::loadScene(const std::string& filepath)
{
#if MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP
    clear();
    CRenderizable::notifyChange();

    // we are taking one of the postprocessing presets to avoid
    // spelling out 20+ single postprocessing flags here.
    m_assimp_scene->scene = (void*)aiImportFile(
        filepath.c_str(), aiProcessPreset_TargetRealtime_MaxQuality);
    m_modelPath = filepath;

    if (m_assimp_scene->scene)
    {
        aiVector3D scene_min, scene_max;
        auto* scene = (aiScene*)m_assimp_scene->scene;
        get_bounding_box(scene, &scene_min, &scene_max);
        m_bbox_min.x = scene_min.x;
        m_bbox_min.y = scene_min.y;
        m_bbox_min.z = scene_min.z;
        m_bbox_max.x = scene_max.x;
        m_bbox_max.y = scene_max.y;
        m_bbox_max.z = scene_max.z;
    }

#else
    THROW_EXCEPTION("MRPT compiled without OpenGL and/or Assimp");
#endif
}

void CAssimpModel::getBoundingBox(
    mrpt::math::TPoint3D& bb_min, mrpt::math::TPoint3D& bb_max) const
{
    bb_min = m_bbox_min;
    bb_max = m_bbox_max;

    // Convert to coordinates of my parent:
    m_pose.composePoint(bb_min, bb_min);
    m_pose.composePoint(bb_max, bb_max);
}

CAssimpModel::TImplAssimp::TImplAssimp() = default;
CAssimpModel::TImplAssimp::~TImplAssimp()
{
#if MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP
    if (scene)
    {
        // cleanup - calling 'aiReleaseImport' is important, as the library
        // keeps internal resources until the scene is freed again. Not
        // doing so can cause severe resource leaking.
        aiReleaseImport((aiScene*)scene);
        scene = nullptr;
    }
#endif
}

bool CAssimpModel::traceRay(const mrpt::poses::CPose3D& o, double& dist) const
{
    // TODO
    return false;
}

#if MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP

static void get_bounding_box_for_node(
    const aiScene* scene, const aiNode* nd, aiVector3D* min, aiVector3D* max,
    aiMatrix4x4* trafo)
{
    aiMatrix4x4 prev;
    unsigned int n = 0, t;

    prev = *trafo;
    aiMultiplyMatrix4(trafo, &nd->mTransformation);

    for (; n < nd->mNumMeshes; ++n)
    {
        const aiMesh* mesh = scene->mMeshes[nd->mMeshes[n]];
        for (t = 0; t < mesh->mNumVertices; ++t)
        {
            aiVector3D tmp = mesh->mVertices[t];
            aiTransformVecByMatrix4(&tmp, trafo);

            min->x = std::min(min->x, tmp.x);
            min->y = std::min(min->y, tmp.y);
            min->z = std::min(min->z, tmp.z);

            max->x = std::max(max->x, tmp.x);
            max->y = std::max(max->y, tmp.y);
            max->z = std::max(max->z, tmp.z);
        }
    }

    for (n = 0; n < nd->mNumChildren; ++n)
    {
        get_bounding_box_for_node(scene, nd->mChildren[n], min, max, trafo);
    }
    *trafo = prev;
}

static void get_bounding_box(
    const aiScene* scene, aiVector3D* min, aiVector3D* max)
{
    aiMatrix4x4 trafo;
    aiIdentityMatrix4(&trafo);

    min->x = min->y = min->z = 1e10f;
    max->x = max->y = max->z = -1e10f;
    get_bounding_box_for_node(scene, scene->mRootNode, min, max, &trafo);
}

static mrpt::img::TColor color4_to_TColor(const aiColor4D& c)
{
    return mrpt::img::TColorf(c.r, c.g, c.b, c.a).asTColor();
}

static mrpt::img::TColor apply_material(const aiMaterial* mtl)
{
    aiColor4D diffuse;
    if (AI_SUCCESS ==
        aiGetMaterialColor(mtl, AI_MATKEY_COLOR_DIFFUSE, &diffuse))
    {
        return color4_to_TColor(diffuse);
    }
    else
    {
        // Default color:
        return {0xa0, 0xa0, 0xa0, 0xff};
    }
}

static mrpt::math::CMatrixDouble44 aiMatrix_to_mrpt(const aiMatrix4x4& m)
{
    mrpt::math::CMatrixDouble44 M;
    M(0, 0) = m.a1;
    M(0, 1) = m.a2;
    M(0, 2) = m.a3;
    M(0, 3) = m.a4;

    M(1, 0) = m.b1;
    M(1, 1) = m.b2;
    M(1, 2) = m.b3;
    M(1, 3) = m.b4;

    M(2, 0) = m.c1;
    M(2, 1) = m.c2;
    M(2, 2) = m.c3;
    M(2, 3) = m.c4;

    M(3, 0) = m.d1;
    M(3, 1) = m.d2;
    M(3, 2) = m.d3;
    M(3, 3) = m.d4;
    return M;
}

static mrpt::math::TPoint3Df to_mrpt(const aiVector3D& v)
{
    return {v.x, v.y, v.z};
}

static void recursive_render(
    const aiScene* sc, const aiNode* nd, const mrpt::poses::CPose3D& transf,
    RenderElements& re)
{
    aiMatrix4x4 m = nd->mTransformation;

    // update transform
    const auto nodeTransf = mrpt::poses::CPose3D(aiMatrix_to_mrpt(m));
    const mrpt::poses::CPose3D curTf = transf + nodeTransf;

    // draw all meshes assigned to this node
    for (unsigned int n = 0; n < nd->mNumMeshes; ++n)
    {
        const struct aiMesh* mesh = sc->mMeshes[nd->mMeshes[n]];

        mrpt::img::TColor color =
            apply_material(sc->mMaterials[mesh->mMaterialIndex]);

        for (unsigned int t = 0; t < mesh->mNumFaces; ++t)
        {
            const struct aiFace* face = &mesh->mFaces[t];

            switch (face->mNumIndices)
            {
                case 1:
                    // GL_POINTS ================
                    for (unsigned int i = 0; i < face->mNumIndices; i++)
                    {
                        // get group index for current index
                        int vertexIndex = face->mIndices[i];
                        if (mesh->mColors[0] != nullptr)
                            color =
                                color4_to_TColor(mesh->mColors[0][vertexIndex]);

                        re.pts_vbd->emplace_back(curTf.composePoint(
                            to_mrpt(mesh->mVertices[vertexIndex])));
                        re.pts_cbd->emplace_back(color);
                    }
                    break;

                case 2:
                    // GL_LINES ================
                    for (unsigned int i = 0; i < face->mNumIndices; i++)
                    {
                        // get group index for current index
                        int vertexIndex = face->mIndices[i];
                        if (mesh->mColors[0] != nullptr)
                            color =
                                color4_to_TColor(mesh->mColors[0][vertexIndex]);

                        re.lines_vbd->emplace_back(curTf.composePoint(
                            to_mrpt(mesh->mVertices[vertexIndex])));
                        re.lines_cbd->emplace_back(color);
                    }
                    break;

                case 3:
                {
                    // GL_TRIANGLES ================
                    const unsigned int nTri = face->mNumIndices / 3;
                    ASSERT_EQUAL_(face->mNumIndices % 3, 0);

                    for (unsigned int iTri = 0; iTri < nTri; iTri++)
                    {
                        mrpt::opengl::TTriangle tri;
                        for (unsigned int v = 0; v < 3; v++)
                        {
                            unsigned int i = iTri * 3 + v;
                            // get group index for current index
                            int vertexIndex = face->mIndices[i];
                            if (mesh->mColors[0] != nullptr)
                                color = color4_to_TColor(
                                    mesh->mColors[0][vertexIndex]);

                            tri.r(v) = color.R;
                            tri.g(v) = color.G;
                            tri.b(v) = color.B;
                            tri.a(v) = color.A;

                            // texture_coordinates_set=0
                            if (mesh->HasTextureCoords(0))
                            {
                                tri.vertices[v].uv.x =
                                    mesh->mTextureCoords[0][vertexIndex].x;
                                tri.vertices[v].uv.y =
                                    mesh->mTextureCoords[0][vertexIndex].y;
                            }

                            if (mesh->mNormals)
                                tri.vertices[v].normal = curTf.rotateVector(
                                    to_mrpt(mesh->mNormals[vertexIndex]));

                            auto pt = curTf.composePoint(
                                to_mrpt(mesh->mVertices[vertexIndex]));
                            tri.x(v) = pt.x;
                            tri.y(v) = pt.y;
                            tri.z(v) = pt.z;
                        }

                        re.tris->emplace_back(std::move(tri));
                    }
                }
                break;
                default:
                    // GL_POLYGON ================
                    THROW_EXCEPTION("ASSIMP polygons not implemented yet.");
                    break;
            }
        }
    }

    // draw all children
    for (unsigned int n = 0; n < nd->mNumChildren; ++n)
        recursive_render(sc, nd->mChildren[n], curTf, re);
}

#endif  // MRPT_HAS_OPENGL_GLUT && MRPT_HAS_ASSIMP