46 lines
1.1 KiB
C
46 lines
1.1 KiB
C
/*
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* matrix.h - 2D matrix operations
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*
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* Written 2010 by Werner Almesberger
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* Copyright 2010 by Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef MATRIX_H
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#define MATRIX_H
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/*
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* 2D transformation:
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*
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* x' = x*a[0][0]+y*a[0][1]+b[0]
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* y' = x*a[1][0]+y*a[1][1]+b[1]
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*/
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struct matrix {
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double a[2][2];
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double b[2];
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};
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void matrix_identity(struct matrix *m);
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void matrix_invert(const double m[2][2], double res[2][2]);
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void matrix_mult(double a[2][2], double b[2][2], double res[2][2]);
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void matrix_multv(const double v[2], double m[2][2], double res[2]);
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void matrix_copy(double from[2][2], double to[2][2]);
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static inline void matrix_map(int x, int y, const struct matrix *m,
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double *res_x, double *res_y)
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{
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*res_x = x*m->a[0][0]+y*m->a[0][1]+m->b[0];
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*res_y = x*m->a[1][0]+y*m->a[1][1]+m->b[1];
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}
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#endif /* !MATRIX_H */
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