TracingMesh.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_RENDERING_GI_TRACING_MESH_H
#define META_OCEAN_RENDERING_GI_TRACING_MESH_H
 
#include "ocean/rendering/globalillumination/GlobalIllumination.h"
#include "ocean/rendering/globalillumination/GITextures.h"
#include "ocean/rendering/globalillumination/TracingObject.h"
 
#include "ocean/math/BoundingBox.h"
#include "ocean/math/BoundingSphere.h"
#include "ocean/math/Triangle3.h"
 
#include "ocean/rendering/Material.h"
#include "ocean/rendering/TriangleFace.h"
 
namespace Ocean
{
 
namespace Rendering
{
 
namespace GlobalIllumination
{
 
/**
 * This class implements the tracing object for a mesh.
 * @ingroup renderinggi
 */
class OCEAN_RENDERING_GI_EXPORT TracingMesh : public TracingObject
{
    private:
 
        /**
         * This class implements a simple octree-like structure allowing to optimized the intersection performance.
         * An octree instance is composed of a bounding box, a set of vertices belonging to the octree and optional octree children.
         */
        class Octree
        {
            public:
 
                /**
                 * Creates a new octree object by a set of given indices and an corresponding mesh object.
                 * @param indices The indices of all vertices which will be covert by the new octree object
                 * @param mesh The mesh holding the entire mesh already
                 */
                Octree(const VertexIndices& indices, const TracingMesh& mesh);
 
                /**
                 * Destructs an octree object.
                 */
                ~Octree();
 
                /**
                 * Determines the nearest intersection with between this tracing object and a given 3D ray.
                 * @see TracingObject::findNearestIntersection().
                 */
                void findNearestIntersection(const Line3& ray, const HomogenousMatrix4& objectTransformation, const HomogenousMatrix4& invertedObjectTransformation, const TracingMesh& mesh, RayIntersection& intersection, const bool frontFace, const Scalar eps, const TracingObject* excludedObject = nullptr) const;
 
                /**
                 * Determines whether this tracing object has an intersection with a provided 3D ray.
                 * @see TracingObject::hasIntersection().
                 */
                bool hasIntersection(const Line3& ray, const HomogenousMatrix4& objectTransformation, const HomogenousMatrix4& invertedObjectTransformation, const TracingMesh& mesh, const Scalar maximalDistance = Numeric::maxValue(), const TracingObject* excludedObject = nullptr) const;
 
            protected:
 
                /// The bounding box of this octree object.
                BoundingBox octreeBoundingBox;
 
                /// This indices of all vertices which are covert by this octree object.
                VertexIndices octreeIndices;
 
                /// Up to eight octree children object, nullptr if a child does not exist.
                Octree* octreeChildren[8];
        };
 
    public:
 
        /**
         * Creates a new tracing object.
         */
        TracingMesh();
 
        /**
         * Destructs this tracing object.
         */
        ~TracingMesh() override;
 
        /**
         * Defines the mesh by setting individual triangles.
         * @param localVertices The entire set of vertices, defined in the local coordinate system
         * @param localNormals The entire set of normals, defined in the local coordinate system, one normal for each vertex
         * @param textureCoordinates The entire set of texture coordinates, one texture coordinate for each vertex
         * @param faces The topology of the mesh, defining the individual triangles, indices with range [0, localVertices.size())
         * @param objectTransformation The transformation of the local coordinate system transforming points defined in the local coordinate system to points defined in the world coordinate system
         * @param localBoundingBox The bounding box of all used vertices, defined in the local coordinate system
         */
        void setTriangles(const Vertices& localVertices, const Normals& localNormals, const TextureCoordinates& textureCoordinates, const TriangleFaces& faces, const HomogenousMatrix4& objectTransformation, const BoundingBox& localBoundingBox);
 
        /**
         * Defines the mesh by setting a triangle strip.
         * @param localVertices The entire set of vertices, defined in the local coordinate system
         * @param localNormals The entire set of normals, defined in the local coordinate system, one normal for each vertex
         * @param textureCoordinates The entire set of texture coordinates, one texture coordinate for each vertex
         * @param indicesSet The topology of the mesh, defining the individual triangles, indices with range [0, localVertices.size())
         * @param objectTransformation The transformation of the local coordinate system transforming points defined in the local coordinate system to points defined in the world coordinate system
         * @param localBoundingBox The bounding box of all used vertices, defined in the local coordinate system
         */
        void setTriangleStrips(const Vertices& localVertices, const Normals& localNormals, const TextureCoordinates& textureCoordinates, const VertexIndexGroups& indicesSet, const HomogenousMatrix4& objectTransformation, const BoundingBox& localBoundingBox);
 
        /**
         * Determines the nearest intersection with between this tracing object and a given 3D ray.
         * @see TracingObject::findNearestIntersection().
         */
        void findNearestIntersection(const Line3& ray, RayIntersection& intersection, const bool frontFace, const Scalar eps, const TracingObject* excludedObject = nullptr) const override;
 
        /**
         * Determines whether this tracing object has an intersection with a provided 3D ray.
         * @see TracingObject::hasIntersection().
         */
        bool hasIntersection(const Line3& ray, const Scalar maximalDistance = Numeric::maxValue(), const TracingObject* excludedObject = nullptr) const override;
 
        /**
         * Determines the amount of light that transmits trough this object in the case e.g., this object is transparent.
         * @see TracingObject::determineDampingColor().
         */
        bool determineDampingColor(const Line3& ray, RGBAColor& color, const Scalar maximalDistance = Numeric::maxValue()) const override;
 
        /**
         * Determines the light (the color) for a specified viewing ray this object does reflect.
         * @see TracingObject::determineColor().
         */
        bool determineColor(const Vector3& viewPosition, const Vector3& viewObjectDirection, const RayIntersection& intersection, const TracingGroup& group, const unsigned int bounces, const TracingObject* excludedObject, const Lighting::LightingModes lightingModes, RGBAColor& color) const override;
 
    private:
 
        /// The bounding box of this tracing object.
        BoundingBox tracingLocalBoundingBox;
 
        /// The bounding sphere of this tracing object.
        BoundingSphere tracingLocalBoundingSphere;
 
        /// The 3D triangles representing the mesh.
        Triangles3 tracingTriangles;
 
        /// The set of normals connected with the mesh's triangles.
        Normals tracingNormals;
 
        /// The set of texture coordinates connected with the mesh's triangles.
        TextureCoordinates tracingTextureCoordinates;
 
        /// The octree used to improved the performance of the intersection determination process.
        Octree* tracingOctree;
};
 
}
 
}
 
}
 
#endif // META_OCEAN_RENDERING_GI_TRACING_MESH_H