CGeneralizedEllipsoidTemplate.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2019, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

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

#include <mrpt/opengl/CGeneralizedEllipsoidTemplate.h>
#include <mrpt/opengl/gl_utils.h>
#include "opengl_internals.h"

using namespace mrpt;
using namespace mrpt::opengl;

using namespace mrpt::math;
using namespace std;

/*---------------------------------------------------------------
                        Render: 2D implementation
  ---------------------------------------------------------------*/
namespace mrpt::opengl::detail
{
template <>
void renderGeneralizedEllipsoidTemplate<2>(
    const std::vector<mrpt::math::CMatrixFixed<float, 2, 1>>& pts,
    const float lineWidth, const uint32_t slices, const uint32_t stacks)
{
#if MRPT_HAS_OPENGL_GLUT
    glEnable(GL_BLEND);
    gl_utils::checkOpenGLError();
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    gl_utils::checkOpenGLError();
    glLineWidth(lineWidth);
    gl_utils::checkOpenGLError();

    glDisable(GL_LIGHTING);  // Disable lights when drawing lines

    glBegin(GL_LINE_LOOP);
    const size_t N = pts.size();
    for (size_t i = 0; i < N; i++) glVertex2f(pts[i][0], pts[i][1]);

    glEnd();

    glEnable(GL_LIGHTING);
    glDisable(GL_BLEND);
#else
    MRPT_UNUSED_PARAM(pts);
    MRPT_UNUSED_PARAM(lineWidth);
    MRPT_UNUSED_PARAM(slices);
    MRPT_UNUSED_PARAM(stacks);
#endif
}

/*---------------------------------------------------------------
                        Render: 3D implementation
  ---------------------------------------------------------------*/
template <>
void renderGeneralizedEllipsoidTemplate<3>(
    const std::vector<mrpt::math::CMatrixFixed<float, 3, 1>>& pts,
    const float lineWidth, const uint32_t slices, const uint32_t stacks)
{
#if MRPT_HAS_OPENGL_GLUT
    glEnable(GL_BLEND);
    gl_utils::checkOpenGLError();
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    gl_utils::checkOpenGLError();
    glLineWidth(lineWidth);
    gl_utils::checkOpenGLError();
    glDisable(GL_LIGHTING);  // Disable lights when drawing lines

    // Points in the ellipsoid:
    //  * "#slices" slices, with "#stacks" points each, but for the two ends
    //  * 1 point at each end slice
    // #total points = stacks*(slices-2) + 2
    ASSERT_EQUAL_((slices - 2) * stacks + 2, pts.size());
    const size_t idx_1st_slice = 1;

    // 1st slice: triangle fan (if it were solid)
    // ----------------------------
    glBegin(GL_LINES);
    for (size_t i = 0; i < stacks; i++)
    {
        glVertex3fv(&pts[0][0]);
        glVertex3fv(&pts[idx_1st_slice + i][0]);
    }
    glEnd();

    // Middle slices: triangle strip (if it were solid)
    // ----------------------------
    for (size_t s = 0; s < slices - 3; s++)
    {
        size_t idx_this_slice = idx_1st_slice + stacks * s;
        size_t idx_next_slice = idx_this_slice + stacks;

        for (size_t i = 0; i < stacks; i++)
        {
            const size_t ii =
                (i == (stacks - 1) ? 0 : i + 1);  // next i with wrapping

            glBegin(GL_LINE_STRIP);
            glVertex3fv(&pts[idx_this_slice + i][0]);
            glVertex3fv(&pts[idx_next_slice + ii][0]);
            glVertex3fv(&pts[idx_next_slice + i][0]);
            glVertex3fv(&pts[idx_this_slice + i][0]);
            glVertex3fv(&pts[idx_this_slice + ii][0]);
            glVertex3fv(&pts[idx_next_slice + ii][0]);
            glEnd();
        }
    }

    // Last slice: triangle fan (if it were solid)
    // ----------------------------
    const size_t idx_last_pt = pts.size() - 1;
    const size_t idx_last_slice = idx_1st_slice + (slices - 3) * stacks;
    glBegin(GL_LINES);
    for (size_t i = 0; i < stacks; i++)
    {
        glVertex3fv(&pts[idx_last_pt][0]);
        glVertex3fv(&pts[idx_last_slice + i][0]);
    }
    glEnd();

    // glBegin( GL_POINTS );
    // const size_t N = pts.size();
    // for (size_t i=0;i<N;i++)
    //  glVertex3f( pts[i][0], pts[i][1], pts[i][2] );
    // glEnd();

    glDisable(GL_BLEND);
    glEnable(GL_LIGHTING);
#else
    MRPT_UNUSED_PARAM(pts);
    MRPT_UNUSED_PARAM(lineWidth);
    MRPT_UNUSED_PARAM(slices);
    MRPT_UNUSED_PARAM(stacks);
#endif
}

/*---------------------------------------------------------------
            generalizedEllipsoidPoints: 2D
  ---------------------------------------------------------------*/
template <>
void generalizedEllipsoidPoints<2>(
    const mrpt::math::CMatrixFixed<double, 2, 2>& U,
    const mrpt::math::CMatrixFixed<double, 2, 1>& mean,
    std::vector<mrpt::math::CMatrixFixed<float, 2, 1>>& out_params_pts,
    const uint32_t numSegments, const uint32_t numSegments_unused)
{
    MRPT_UNUSED_PARAM(numSegments_unused);
    out_params_pts.clear();
    out_params_pts.reserve(numSegments);
    const double Aa = 2 * M_PI / numSegments;
    for (double ang = 0; ang < 2 * M_PI; ang += Aa)
    {
        const double ccos = cos(ang);
        const double ssin = sin(ang);

        out_params_pts.resize(out_params_pts.size() + 1);

        auto& pt = out_params_pts.back();

        pt[0] = mean[0] + ccos * U(0, 0) + ssin * U(0, 1);
        pt[1] = mean[1] + ccos * U(1, 0) + ssin * U(1, 1);
    }
}

inline void aux_add3DpointWithEigenVectors(
    const double x, const double y, const double z,
    std::vector<mrpt::math::CMatrixFixed<float, 3, 1>>& pts,
    const mrpt::math::CMatrixFixed<double, 3, 3>& M,
    const mrpt::math::CMatrixFixed<double, 3, 1>& mean)
{
    pts.resize(pts.size() + 1);
    mrpt::math::CMatrixFixed<float, 3, 1>& pt = pts.back();
    pt[0] = mean[0] + x * M(0, 0) + y * M(0, 1) + z * M(0, 2);
    pt[1] = mean[1] + x * M(1, 0) + y * M(1, 1) + z * M(1, 2);
    pt[2] = mean[2] + x * M(2, 0) + y * M(2, 1) + z * M(2, 2);
}

/*---------------------------------------------------------------
            generalizedEllipsoidPoints: 3D
  ---------------------------------------------------------------*/
template <>
void generalizedEllipsoidPoints<3>(
    const mrpt::math::CMatrixFixed<double, 3, 3>& U,
    const mrpt::math::CMatrixFixed<double, 3, 1>& mean,
    std::vector<mrpt::math::CMatrixFixed<float, 3, 1>>& pts,
    const uint32_t slices, const uint32_t stacks)
{
    MRPT_START
    ASSERT_ABOVEEQ_(slices, 3);
    ASSERT_ABOVEEQ_(stacks, 3);
    // sin/cos cache --------
    // Slices: [0,pi]
    std::vector<double> slice_cos(slices), slice_sin(slices);
    for (uint32_t i = 0; i < slices; i++)
    {
        double angle = M_PI * i / double(slices - 1);
        slice_sin[i] = sin(angle);
        slice_cos[i] = cos(angle);
    }
    // Stacks: [0,2*pi]
    std::vector<double> stack_sin(stacks), stack_cos(stacks);
    for (uint32_t i = 0; i < stacks; i++)
    {
        double angle = 2 * M_PI * i / double(stacks);
        stack_sin[i] = sin(angle);
        stack_cos[i] = cos(angle);
    }

    // Points in the ellipsoid:
    //  * "#slices" slices, with "#stacks" points each, but for the two ends
    //  * 1 point at each end slice
    // #total points = stacks*(slices-2) + 2
    pts.clear();
    pts.reserve((slices - 2) * stacks + 2);

    for (uint32_t i = 0; i < slices; i++)
    {
        if (i == 0)
            aux_add3DpointWithEigenVectors(1, 0, 0, pts, U, mean);
        else if (i == (slices - 1))
            aux_add3DpointWithEigenVectors(-1, 0, 0, pts, U, mean);
        else
        {
            const double x = slice_cos[i];
            const double R = slice_sin[i];

            for (uint32_t j = 0; j < stacks; j++)
            {
                const double y = R * stack_cos[j];
                const double z = R * stack_sin[j];
                aux_add3DpointWithEigenVectors(x, y, z, pts, U, mean);
            }
        }
    }

    MRPT_END
}
}  // namespace mrpt::opengl::detail