CollisionShapeCache.cpp

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/*+-------------------------------------------------------------------------+
  |                       MultiVehicle simulator (libmvsim)                 |
  |                                                                         |
  | Copyright (C) 2014-2024  Jose Luis Blanco Claraco                       |
  | Copyright (C) 2017  Borys Tymchenko (Odessa Polytechnic University)     |
  | Distributed under 3-clause BSD License                                  |
  |   See COPYING                                                           |
  +-------------------------------------------------------------------------+ */
 
#include <box2d/b2_settings.h>  // b2_maxPolygonVertices
#include <mrpt/opengl/CAssimpModel.h>
#include <mrpt/opengl/CBox.h>
#include <mrpt/opengl/CCylinder.h>
#include <mrpt/opengl/CSphere.h>
#include <mrpt/version.h>
#include <mvsim/CollisionShapeCache.h>
 
using namespace mvsim;
 
CollisionShapeCache& CollisionShapeCache::Instance()
{
        static CollisionShapeCache o;
        return o;
}
 
Shape2p5 CollisionShapeCache::get(
        mrpt::opengl::CRenderizable& obj, float zMin, float zMax, const mrpt::poses::CPose3D& modelPose,
        const float modelScale, const std::optional<std::string>& modelFile)
{
        // already cached?
        if (modelFile)
        {
                if (auto it = cache.find(modelFile.value()); it != cache.end()) return it->second.shape;
        }
 
        // No, it's a new model path, create its placeholder:
        Shape2p5 retVal;
        Shape2p5& ret = modelFile ? cache[*modelFile].shape : retVal;
 
        // Now, decide whether it's a simple geometry, or an arbitrary model:
        const auto simpleGeom = processSimpleGeometries(obj, zMin, zMax, modelPose, modelScale);
 
        if (simpleGeom)
        {
                ret = simpleGeom.value();
        }
        else
        {
                ret = processGenericGeometry(obj, zMin, zMax, modelPose, modelScale);
        }
 
        const auto vol = ret.volume();
 
#if 0
        std::cout << "shape2.5 for ["
                          << (modelFile.has_value() ? *modelFile : "none")
                          << "] glClass=" << obj.GetRuntimeClass()->className
                          << " shape=" << ret.getContour().size() << " pts, "
                          << " volume=" << vol << " zMin=" << zMin << " zMax=" << zMax
                          << " modelScale= " << modelScale
                          << " was simpleGeom=" << (simpleGeom ? "yes" : "no") << "\n"
                          << ret.getContour().asYAML() << "\n\n";
#endif
 
        if (vol < 1e-8)
        {
                THROW_EXCEPTION_FMT(
                        "Error: Collision volume for visual model ('%s') has almost null "
                        "volume (=%g m³). A possible cause, if this is a <block>, is not "
                        "enough vertices within the given range [zmin,zmax]",
                        modelFile.has_value() ? modelFile->c_str() : "none", vol);
        }
 
        return ret;
}
 
std::optional<Shape2p5> CollisionShapeCache::processSimpleGeometries(
        const mrpt::opengl::CRenderizable& obj, float zMin, float zMax,
        const mrpt::poses::CPose3D& modelPose, const float modelScale)
{
#if MRPT_VERSION >= 0x260
        using namespace mrpt::literals;  // _deg
#else
        using namespace mrpt;  // _deg
#endif
 
        if (auto oCyl = dynamic_cast<const mrpt::opengl::CCylinder*>(&obj); oCyl)
        {
                // ===============================
                // Cylinder
                // ===============================
                // If the cylinder is not upright, skip and go for the generic algorithm
                if (std::abs(modelPose.pitch()) > 0.02_deg || std::abs(modelPose.roll()) > 0.02_deg)
                        return {};
 
                const size_t actualEdgeCount = oCyl->getSlicesCount();
                double actualRadius = std::max<double>(oCyl->getTopRadius(), oCyl->getBottomRadius());
 
                return processCylinderLike(
                        actualEdgeCount, actualRadius, zMin, zMax, modelPose, modelScale);
        }
        else if (auto oSph = dynamic_cast<const mrpt::opengl::CSphere*>(&obj); oSph)
        {
                // ===============================
                // Sphere
                // ===============================
#if MRPT_VERSION >= 0x271
                const size_t actualEdgeCount = oSph->getNumberOfSegments();
#else
                // workaround mrpt <2.7.1
                const size_t actualEdgeCount =
                        const_cast<mrpt::opengl::CSphere*>(oSph)->getNumberOfSegments();
#endif
 
                double actualRadius = oSph->getRadius();
 
                return processCylinderLike(
                        actualEdgeCount, actualRadius, zMin, zMax, modelPose, modelScale);
        }
        else if (auto oBox = dynamic_cast<const mrpt::opengl::CBox*>(&obj); oBox)
        {
                // ===============================
                // Box
                // ===============================
                // If the object is not upright, skip and go for the generic algorithm
                if (std::abs(modelPose.pitch()) > 0.02_deg || std::abs(modelPose.roll()) > 0.02_deg)
                        return {};
 
                mrpt::math::TPoint3D p1, p2;
                oBox->getBoxCorners(p1, p2);
                p1 *= modelScale;
                p2 *= modelScale;
 
                const mrpt::math::TPoint3D corners[4] = {
                        modelPose.composePoint({p1.x, p1.y, 0}), modelPose.composePoint({p1.x, p2.y, 0}),
                        modelPose.composePoint({p2.x, p2.y, 0}), modelPose.composePoint({p2.x, p1.y, 0})};
 
                mrpt::math::TPolygon2D contour;
                for (int i = 0; i < 4; i++) contour.emplace_back(corners[i].x, corners[i].y);
 
                Shape2p5 s;
                s.setShapeManual(contour, zMin, zMax);
                return {s};
        }
        else
        {
                // unknown:
                return {};
        }
}
 
Shape2p5 CollisionShapeCache::processGenericGeometry(
        mrpt::opengl::CRenderizable& obj, float zMin, float zMax, const mrpt::poses::CPose3D& modelPose,
        const float modelScale)
{
        Shape2p5 ret;
 
        // Make sure the points and vertices buffers are up to date, so we can
        // access them:
        auto* oAssimp = dynamic_cast<mrpt::opengl::CAssimpModel*>(&obj);
        if (oAssimp)
        {
                oAssimp->onUpdateBuffers_all();
        }
        auto* oRSWF = dynamic_cast<mrpt::opengl::CRenderizableShaderWireFrame*>(&obj);
        if (oRSWF)
        {
                oRSWF->onUpdateBuffers_Wireframe();
        }
        auto* oRST = dynamic_cast<mrpt::opengl::CRenderizableShaderTriangles*>(&obj);
        if (oRST)
        {
                oRST->onUpdateBuffers_Triangles();
        }
        auto* oRSTT = dynamic_cast<mrpt::opengl::CRenderizableShaderTexturedTriangles*>(&obj);
        if (oRSTT)
        {
                oRSTT->onUpdateBuffers_TexturedTriangles();
        }
        auto* oRP = dynamic_cast<mrpt::opengl::CRenderizableShaderPoints*>(&obj);
        if (oRP)
        {
                oRP->onUpdateBuffers_Points();
        }
 
        // Slice bbox in z up to a given relevant height:
        size_t numTotalPts = 0, numPassedPts = 0;
 
        auto rawBB = obj.getBoundingBox();
        // transform and scale BBox too:
        rawBB.max *= modelScale;
        rawBB.min *= modelScale;
        const auto coarseBB = rawBB.compose(modelPose);
        ret.buildInit(
                mrpt::math::TPoint2Df(coarseBB.min.x, coarseBB.min.y),
                mrpt::math::TPoint2Df(coarseBB.max.x, coarseBB.max.y));
 
        auto lambdaUpdatePt = [&](const mrpt::math::TPoint3Df& orgPt)
        {
                numTotalPts++;
                auto pt = modelPose.composePoint(orgPt * modelScale);
                if (pt.z < zMin || pt.z > zMax) return;  // skip
                ret.buildAddPoint(pt);
                numPassedPts++;
        };
        auto lambdaUpdateTri = [&](const mrpt::opengl::TTriangle& tri)
        {
                numTotalPts += 3;
                // transform the whole triangle, then compare with [z,z] limits:
                mrpt::opengl::TTriangle t = tri;
                for (int i = 0; i < 3; i++) t.vertex(i) = modelPose.composePoint(t.vertex(i) * modelScale);
 
                // does any of the point lie within the valid Z range, or is the
                // triangle going all the way down to top?
                bool outDown = false, outUp = false, anyIn = false;
                for (int i = 0; i < 3; i++)
                {
                        const auto& p = t.vertex(i);
                        if (p.z >= zMin && p.z <= zMax)
                        {
                                anyIn = true;
                                break;
                        }
                        if (p.z > zMax) outUp = true;
                        if (p.z < zMin) outDown = true;
                }
                if (!(anyIn || (outUp && outDown))) return;      // skip triangle
 
                ret.buildAddTriangle(t);
                numPassedPts += 3;
        };
 
        if (oRST)
        {
                auto lck = mrpt::lockHelper(oRST->shaderTrianglesBufferMutex().data);
                const auto& tris = oRST->shaderTrianglesBuffer();
                for (const auto& tri : tris) lambdaUpdateTri(tri);
        }
        if (oRSTT)
        {
                auto lck = mrpt::lockHelper(oRSTT->shaderTexturedTrianglesBufferMutex().data);
                const auto& tris = oRSTT->shaderTexturedTrianglesBuffer();
                for (const auto& tri : tris) lambdaUpdateTri(tri);
        }
        if (oRP)
        {
                auto lck = mrpt::lockHelper(oRP->shaderPointsBuffersMutex().data);
                const auto& pts = oRP->shaderPointsVertexPointBuffer();
                for (const auto& pt : pts) lambdaUpdatePt(pt);
        }
        if (oRSWF)
        {
                auto lck = mrpt::lockHelper(oRSWF->shaderWireframeBuffersMutex().data);
                const auto& pts = oRSWF->shaderWireframeVertexPointBuffer();
                for (const auto& pt : pts) lambdaUpdatePt(pt);
        }
 
#if MRPT_VERSION >= 0x260
        if (oAssimp)
        {
                const auto& txtrdObjs = oAssimp->texturedObjects();      // mrpt>=2.6.0
                for (const auto& o : txtrdObjs)
                {
                        if (!o) continue;
 
                        auto lck = mrpt::lockHelper(o->shaderTexturedTrianglesBufferMutex().data);
                        const auto& tris = o->shaderTexturedTrianglesBuffer();
                        for (const auto& tri : tris) lambdaUpdateTri(tri);
                }
        }
#endif
 
        // Convert all points into an actual 2.5D volume:
        // ---------------------------------------------------------
        ret.clipZMin(zMin);
        ret.clipZMax(zMax);
 
        ret.getContour();  // evalute it now
 
        return ret;
}
 
Shape2p5 CollisionShapeCache::processCylinderLike(
        const size_t actualEdgeCount, double actualRadius, float zMin, float zMax,
        const mrpt::poses::CPose3D& modelPose, const float modelScale)
{
        const size_t maxEdges = b2_maxPolygonVertices;
 
        const auto nFaces = std::min<size_t>(maxEdges, actualEdgeCount);
 
        const bool isApprox = actualEdgeCount > maxEdges;
        if (isApprox)
        {
                const int i = mrpt::round(nFaces / 4);
                double newR = actualRadius;
                for (int j = -1; j <= 1; j++)
                {
                        const double ang = (i + j) * 2 * M_PI / nFaces;
                        const double angp1 = (i + j + 1) * 2 * M_PI / nFaces;
                        const mrpt::math::TPoint2D pt0 = {cos(ang), sin(ang)};
                        const mrpt::math::TPoint2D pt1 = {cos(angp1), sin(angp1)};
 
                        const double midDist = ((pt0 + pt1) * 0.5).norm();
 
                        newR = std::max(newR, actualRadius * (1.0 / midDist));
                }
                actualRadius = newR;
        }
 
        mrpt::math::TPolygon2D contour;
        for (size_t i = 0; i < nFaces; i++)
        {
                const double ang = i * 2 * M_PI / nFaces;
                const mrpt::math::TPoint3D localPt = {cos(ang) * actualRadius, sin(ang) * actualRadius, .0};
                const auto pt = modelPose.composePoint(localPt * modelScale);
                contour.emplace_back(pt.x, pt.y);
        }
 
        Shape2p5 s;
        s.setShapeManual(contour, zMin, zMax);
        return {s};
}