IMatrix4x4.h

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/*

AmnesiaEngine
Copyright (c) 2006 John DiSanti.

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, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

*/

#ifndef AMN_IMATRIX4X4_H
#define AMN_IMATRIX4X4_H

namespace amn
{

class IMatrix4x4
{
public:
        IMatrix4x4()
        {
                loadIdentity(); 
        }
        IMatrix4x4(IMatrix4x4& copy)
        {
                setMatrix(copy);
        }

        const float* getMatrixPointer()
        {
                return mat;
        }

        void loadIdentity()
        {
                mat[0] = 1; mat[4] = 0;
                mat[1] = 0; mat[5] = 1;
                mat[2] = 0; mat[6] = 0;
                mat[3] = 0; mat[7] = 0;
                mat[8] = 0; mat[12]= 0;
                mat[9] = 0; mat[13]= 0;
                mat[10]= 1; mat[14]= 0;
                mat[11]= 0; mat[16]= 1;
        }

        void setMatrix(IMatrix4x4& copy)
        {
                int i;
                for(i = 0; i < 16; i++)
                        mat[i] = copy.getMatrixPointer()[i];
        }

        void setMatrix(const float* copy)
        {
                if(!copy)
                        return;

                int i;
                for(i = 0; i < 16; i++)
                        mat[i] = copy[i];
        }

        float getElement(unsigned short id)
        {
                return mat[id];
        }

        float operator[] (int id)
        {
                return mat[id];
        }

        IMatrix4x4& operator *= (IMatrix4x4& m)
        {
                /* Example of 3x3 multiplication, remember we are doing 4x4...
                [ a b c ]       [ j i h ]       [ aj+bk+cn  ai+bl+co  ah+bm+cp ]
                [ d e f ]   x   [ k l m ]   =   [ dj+ek+fn  di+el+fo  dh+em+fp ]
                [ g h i ]       [ n o p ]       [ gj+hk+in  gi+hl+io  gh+hm+ip ]
                */
                const float* c = m.getMatrixPointer();

                mat[0] = mat[0] * c[0] + mat[1] * c[4] + mat[2] * c[8] + mat[3] * c[12];
                mat[1] = mat[0] * c[1] + mat[1] * c[5] + mat[2] * c[9] + mat[3] * c[13];
                mat[2] = mat[0] * c[2] + mat[1] * c[6] + mat[2] * c[10]+ mat[3] * c[14];
                mat[3] = mat[0] * c[3] + mat[1] * c[7] + mat[2] * c[11]+ mat[3] * c[15];

                mat[4] = mat[4] * c[0] + mat[5] * c[4] + mat[6] * c[8] + mat[7] * c[12];
                mat[5] = mat[4] * c[1] + mat[5] * c[5] + mat[6] * c[9] + mat[7] * c[13];
                mat[6] = mat[4] * c[2] + mat[5] * c[6] + mat[6] * c[10]+ mat[7] * c[14];
                mat[7] = mat[4] * c[3] + mat[5] * c[7] + mat[6] * c[11]+ mat[7] * c[15];

                mat[8] = mat[8] * c[0] + mat[9] * c[4] + mat[10]* c[8] + mat[11]* c[12];
                mat[9] = mat[8] * c[1] + mat[9] * c[5] + mat[10]* c[9] + mat[11]* c[13];
                mat[10]= mat[8] * c[2] + mat[9] * c[6] + mat[10]* c[10]+ mat[11]* c[14];
                mat[11]= mat[8] * c[3] + mat[9] * c[7] + mat[10]* c[11]+ mat[11]* c[15];

                mat[12]= mat[12]* c[0] + mat[13]* c[4] + mat[14]* c[8] + mat[15]* c[12];
                mat[13]= mat[12]* c[1] + mat[13]* c[5] + mat[14]* c[9] + mat[15]* c[13];
                mat[14]= mat[12]* c[2] + mat[13]* c[6] + mat[14]* c[10]+ mat[15]* c[14];
                mat[15]= mat[12]* c[3] + mat[13]* c[7] + mat[14]* c[11]+ mat[15]* c[15];

                return *this;
        }

        IMatrix4x4& operator *= (float s)
        {
                int i;
                for(i = 0; i < 16; i++)
                        mat[i] *= s;

                return *this;
        }

        IMatrix4x4& operator += (IMatrix4x4& m)
        {
                const float* c = m.getMatrixPointer();
                int i;
                for(i = 0; i < 4; i++)
                        mat[i] = mat[i] + c[i*4];
                for(i = 4; i < 8; i++)
                        mat[i] = mat[i] + c[i*4];
                for(i = 8; i < 12; i++)
                        mat[i] = mat[i] + c[i*4];
                for(i = 12; i < 16; i++)
                        mat[i] = mat[i] + c[i*4];
        }

        IMatrix4x4& operator -= (IMatrix4x4& m)
        {
                const float* c = m.getMatrixPointer();
                int i;
                for(i = 0; i < 4; i++)
                        mat[i] = mat[i] - c[i*4];
                for(i = 4; i < 8; i++)
                        mat[i] = mat[i] - c[i*4];
                for(i = 8; i < 12; i++)
                        mat[i] = mat[i] - c[i*4];
                for(i = 12; i < 16; i++)
                        mat[i] = mat[i] - c[i*4];
        }

private:
        float mat[16];
};

};

#endif//AMN_IMATRIX4X4_H

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