subdiv_sphere.hpp

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#pragma once
#ifndef OGLPLUS_SHAPES_SUBDIV_SPHERE_1309171555_HPP
#define OGLPLUS_SHAPES_SUBDIV_SPHERE_1309171555_HPP

#include <oglplus/face_mode.hpp>
#include <oglplus/shapes/draw.hpp>

#include <oglplus/shapes/vert_attr_info.hpp>
#include <oglplus/math/vector.hpp>
#include <oglplus/math/sphere.hpp>

#include <map>

namespace oglplus {
namespace shapes {

OGLPLUS_ENUM_CLASS_BEGIN(SubdivSphereInitialShape, GLuint)
    OGLPLUS_ENUM_CLASS_VALUE(Icosahedron, 0)
    OGLPLUS_ENUM_CLASS_COMMA
    OGLPLUS_ENUM_CLASS_VALUE(Octohedron, 1)
    OGLPLUS_ENUM_CLASS_COMMA
    OGLPLUS_ENUM_CLASS_VALUE(Tetrahedron, 2)
OGLPLUS_ENUM_CLASS_END(SubdivSphereInitialShape)

class SimpleSubdivSphere
 : public DrawingInstructionWriter
 , public DrawMode
{
private:
    GLuint _subdivs;
    std::vector<GLdouble> _positions;
    std::vector<GLuint> _indices;

    typedef std::pair<GLuint, GLuint> _edge;
    std::map<_edge, GLuint> _midpoints;

    GLuint _midpoint(GLuint ia, GLuint ib);
    void _subdivide(GLuint ia, GLuint ib, GLuint ic, GLuint levels);
    void _make_face(GLuint ia, GLuint ib, GLuint ic, GLuint levels);

    void _init_icosah(void);
    void _init_tetrah(void);
    void _init_octoh(void);
public:
    typedef SubdivSphereInitialShape InitialShape;

    SimpleSubdivSphere(void)
     : _subdivs(2)
    {
        _init_icosah();
    }

    SimpleSubdivSphere(GLuint subdivs)
     : _subdivs(subdivs)
    {
        _init_icosah();
    }

    SimpleSubdivSphere(GLuint subdivs, InitialShape init_shape);

    FaceOrientation FaceWinding(void) const
    {
        return FaceOrientation::CCW;
    }

    typedef GLuint (SimpleSubdivSphere::*VertexAttribFunc)(std::vector<GLfloat>&) const;

    template <typename T>
    GLuint Positions(std::vector<T>& dest) const
    {
        dest.assign(_positions.begin(), _positions.end());
        return 3;
    }

#if OGLPLUS_DOCUMENTATION_ONLY

    typedef VertexAttribsInfo<SubdivSphere> VertexAttribs;
#else
    typedef VertexAttribsInfo<
        SimpleSubdivSphere,
        std::tuple<VertexPositionsTag>
    > VertexAttribs;
#endif

    template <typename T>
    void BoundingSphere(oglplus::Sphere<T>& bounding_sphere) const
    {
        bounding_sphere = oglplus::Sphere<T>(T(0), T(0), T(0), T(1));
    }

    typedef std::vector<GLuint> IndexArray;

    IndexArray Indices(Default = Default()) const
    {
        return IndexArray(_indices.begin(), _indices.end());
    }

    DrawingInstructions Instructions(PrimitiveType mode) const;

    DrawingInstructions Instructions(Default = Default()) const
    {
        return Instructions(PrimitiveType::Triangles);
    }
};

} // shapes
} // oglplus

#if !OGLPLUS_LINK_LIBRARY || defined(OGLPLUS_IMPLEMENTING_LIBRARY)
#include <oglplus/shapes/subdiv_sphere.ipp>
#endif // OGLPLUS_LINK_LIBRARY

#endif // include guard