mesh.h

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/*
    toxic - A Global Illumination Renderer
    Copyright (C) 2003-2004 Francois Beaune
    Contact: http://toxicengine.sourceforge.net/

    This file is part of toxic.

    toxic is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    toxic is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with toxic; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef TOXIC_RENDERER_MESH_H
#define TOXIC_RENDERER_MESH_H

#include "common/math/aabb3.h"
#include "common/math/matrix4.h"
#include "common/math/octree.h"
#include "common/math/point2.h"
#include "common/math/point3.h"
#include "common/math/real.h"
#include "common/math/vector2.h"
#include "common/math/vector3.h"
#include "color3.h"
#include "globals.h"
#include "hit.h"
#include "iarealight.h"

#include <cassert>
#include <vector>

namespace toxic {

    class Context;
    class Framebuffer;
    class ICamera;
    class ISurfaceShader;
    class Ray;
    class Scene;

    class Mesh : public IAreaLight {
        friend class MeshBuilder;
    public:
        //! m is the object space to world space transformation matrix.
        Mesh(
            const sheep::Matrix4 &m,
            const ISurfaceShader *surface_shader,
            IntersectionMask intersection_mask = INTERSECT_ALL_RAYS);

        virtual ~Mesh();

        typedef unsigned int FeatureId;

        FeatureId AppendVertex(const sheep::Point3 &v);
        FeatureId AppendNormal(const sheep::Vector3 &vn);
        FeatureId AppendTexCoord(const sheep::Vector2 &vt);
        FeatureId AppendTriangle(FeatureId v0, FeatureId v1, FeatureId v2);
        void SetTriangleNormals(FeatureId tri, FeatureId n0, FeatureId n1, FeatureId n2);
        void SetTriangleTexCoords(FeatureId tri, FeatureId t0, FeatureId t1, FeatureId t2);

        //! This method must be called only once, after the object is completely
        //! configured, and before it is used for the first time.
        virtual void Finalize(const Context &context);

        //! Returns the Axis Aligned Bounding Box of this object. The AABB is
        //! expressed in world space.
        virtual const sheep::AABB3 &GetAABB() const;

        //! Computes the surface area of this object.
        virtual sheep::Real ComputeSurfaceArea() const;

        //! Given a point in the unit square (the set of points in [0..1]^2),
        //! this method computes the corresponding surface point and normal
        //! (both are expressed in world space).
        virtual void EvaluateSurface(
            const sheep::Point2 &input,
            sheep::Point3 *point,
            sheep::Vector3 *geometric_normal
        ) const;

        //! This method returns true if the ray intersect the object, or false otherwise.
        //! If 'hit' is not null, intersection data are reported through the 'hit' parameter
        //! (only if an intersection has been found; if no intersection has been found, the
        //! 'hit' parameter is left unchanged). The ray is expressed in world space.
        virtual bool Intersect(
            const Context &context,
            const Ray &ray,
            Hit *hit = 0
        ) const;

        virtual void Annotate(
            const Context &context,
            const ICamera *camera,
            Framebuffer *framebuffer
        ) const;

    private:
        struct triangle {
#ifdef USE_MAILBOXES
            //!\todo Allocate one ray id per rendering thread.
            mutable int m_mailbox_ray_id;   //!< Id of the last ray tested against this triangle.
#endif  // USE_MAILBOXES

            int m_v0, m_v1, m_v2;       //!< Vertex indices.
            int m_n0, m_n1, m_n2;       //!< Vertex normal indices.
            int m_t0, m_t1, m_t2;       //!< Texture coordinate indices.

            sheep::Vector3 m_geometric_normal;  //!< Geometric normal to the triangle surface (unit-length) expressed in object space.

            triangle();
        };

        typedef std::vector<sheep::Point3> vertex_vector;
        typedef std::vector<sheep::Vector3> normal_vector;
        typedef std::vector<sheep::Vector2> texcoord_vector;
        typedef std::vector<triangle> triangle_vector;

        typedef vertex_vector::iterator vertex_vector_it;
        typedef triangle_vector::iterator triangle_vector_it;
        typedef vertex_vector::const_iterator vertex_vector_const_it;
        typedef triangle_vector::const_iterator triangle_vector_const_it;

        typedef sheep::Octree<const triangle *> octree;
        typedef sheep::OctreeNode<const triangle *> octree_node;

        struct triangle_voxel_intersector {
            const vertex_vector &m_vertices;

            triangle_voxel_intersector(const vertex_vector &vertices) :
                m_vertices(vertices) {}

            bool Intersect(const triangle *tri, const sheep::AABB3 &voxel) const;
        };

        //! This visitor is invoked by the Mesh::Intersect() method when the hit
        //! parameter is 0 (null). It is aimed at testing whether the ray touches
        //! an object in the octree or not. It does not search for the nearest
        //! object and it does not compute the intersection distance.
        struct octree_test_visitor {
            const vertex_vector &m_vertices;
            const Context &m_context;
            const Ray &m_ray;
            bool m_found;

            octree_test_visitor(
                const vertex_vector &vertices,
                const Context &context,
                const Ray &ray);

            bool Trace(const octree_node *node, sheep::Real t0, sheep::Real t1);
        };

        //! This visitor is invoked by the Mesh::Intersect() method when the hit
        //! parameter is not null. It searches for the nearest intersected object
        //! and reports the intersection distance.
        struct octree_full_visitor {
            const vertex_vector &m_vertices;
            const Context &m_context;
            const Ray &m_ray;
            sheep::Real m_t, m_u, m_v;
            const triangle *m_triangle;

            octree_full_visitor(
                const vertex_vector &vertices,
                const Context &context,
                const Ray &ray);

            bool Trace(const octree_node *node, sheep::Real t0, sheep::Real t1);
        };

        vertex_vector m_vertices;
        normal_vector m_normals;
        texcoord_vector m_texcoords;
        triangle_vector m_triangles;

        octree *m_octree;       //!< Used only if the mesh contains enough triangles.

        sheep::AABB3 m_aabb;    //!< Bounding box of the object, expressed in world space.

        void finalize_geometry();
    };

#include "mesh.inl"

}

#endif  // !TOXIC_RENDERER_MESH_H

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