spheregenerator.cpp

// © Copyright 2010 - 2016 BlackTopp Studios Inc.
/* This file is part of The Mezzanine Engine.

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*/
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/*
 -----------------------------------------------------------------------------
 This source file is part of ogre-procedural

 For the latest info, see http://code.google.com/p/ogre-procedural/

 Copyright (c) 2010-2013 Michael Broutin

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 THE SOFTWARE.
 -----------------------------------------------------------------------------
 */
#ifndef _graphicsproceduralspheregenerator_cpp
#define _graphicsproceduralspheregenerator_cpp

#include "Graphics/Procedural/Mesh/spheregenerator.h"

#include "MathTools/mathtools.h"
#include "exception.h"

namespace Mezzanine
{
    namespace Graphics
    {
        namespace Procedural
        {
            SphereGenerator::SphereGenerator(const Real Radius, const Whole Rings, const Whole SegCircle) :
                SphereRadius(Radius),
                NumRings(Rings),
                NumSegCircle(SegCircle)
                {  }

            SphereGenerator::~SphereGenerator()
                {  }

            ///////////////////////////////////////////////////////////////////////////////
            // Utility

            void SphereGenerator::AddToTriangleBuffer(TriangleBuffer& Buffer) const
            {
                Buffer.RebaseOffset();
                Buffer.EstimateVertexCount( ( this->NumRings + 1 ) * ( this->NumSegCircle + 1 ) );
                Buffer.EstimateIndexCount( this->NumRings * ( this->NumSegCircle + 1 ) * 6 );

                Real fDeltaRingAngle = ( MathTools::GetPi() / this->NumRings );
                Real fDeltaSegAngle = ( MathTools::GetTwoPi() / this->NumSegCircle );
                Integer Offset = 0;

                // Generate the group of rings for the sphere
                for( Whole Ring = 0 ; Ring <= this->NumRings ; ++Ring )
                {
                    Real r0 = this->SphereRadius * sinf( Ring * fDeltaRingAngle );
                    Real y0 = this->SphereRadius * cosf( Ring * fDeltaRingAngle );

                    // Generate the group of segments for the current ring
                    for( Whole Segment = 0 ; Segment <= this->NumSegCircle ; ++Segment )
                    {
                        Real x0 = r0 * sinf( Segment * fDeltaSegAngle );
                        Real z0 = r0 * cosf( Segment * fDeltaSegAngle );

                        // Add one vertex to the strip which makes up the sphere
                        this->AddPoint(Buffer, Vector3(x0, y0, z0),
                                       Vector3(x0, y0, z0).GetNormal(),
                                       Vector2( (Real)Segment / (Real)this->NumSegCircle, (Real)Ring / (Real)this->NumRings ) );

                        if( Ring != this->NumRings ) {
                            if( Segment != this->NumSegCircle ) {
                                // each vertex (except the last) has six indices pointing to it
                                if( Ring != this->NumRings - 1 ) {
                                    Buffer.AddTriangle(Offset + this->NumSegCircle + 2, Offset, Offset + this->NumSegCircle + 1);
                                }
                                if( Ring != 0 ) {
                                    Buffer.AddTriangle(Offset + this->NumSegCircle + 2, Offset + 1, Offset);
                                }
                            }
                            Offset++;
                        }
                    }// for each segment
                }// for each ring
            }

            ///////////////////////////////////////////////////////////////////////////////
            // Configuration

            SphereGenerator& SphereGenerator::SetRadius(const Real Radius)
            {
                if( Radius <= 0.0 )
                    MEZZ_EXCEPTION(ExceptionBase::PARAMETERS_EXCEPTION,"Radius for a generated sphere mesh must be greater than zero.");

                this->SphereRadius = Radius;
                return *this;
            }

            SphereGenerator& SphereGenerator::SetNumRings(const Whole Rings)
            {
                if( Rings == 0 )
                    MEZZ_EXCEPTION(ExceptionBase::PARAMETERS_EXCEPTION,"Number of rings for generated sphere mesh must be greater than zero.");

                this->NumRings = Rings;
                return *this;
            }

            SphereGenerator& SphereGenerator::SetNumSegCircle(const Whole SegCircle)
            {
                if( SegCircle < 3 )
                    MEZZ_EXCEPTION(ExceptionBase::PARAMETERS_EXCEPTION,"Number of segments for circular component of generated cylinder mesh must be greater than two.");

                this->NumSegCircle = SegCircle;
                return *this;
            }
        }//Procedural
    }//Graphics
}//Mezzanine

#endif