Initial commit. For older history, see project ben-scans.

http://projects.qi-hardware.com/index.php/p/ben-scans/

solidify/matrix.c

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+/*
+ * matrix.c - 2D matrix operations
+ *
+ * Written 2010 by Werner Almesberger
+ * Copyright 2010 by Werner Almesberger
+ *
+ * This program 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.
+ */
+
+
+#include <assert.h>
+
+#include "matrix.h"
+
+
+void matrix_identity(struct matrix *m)
+{
+	m->a[0][0] = m->a[1][1] = 1;
+	m->a[0][1] = m->a[1][0] = 0;
+	m->b[0] = m->b[1] = 0;
+}
+
+
+void matrix_invert(const double m[2][2], double res[2][2])
+{
+	double det = m[0][0]*m[1][1]-m[0][1]*m[1][0];
+
+	assert(res != (void *) m);
+	res[0][0] = m[1][1]/det;
+	res[0][1] = -m[0][1]/det;
+	res[1][0] = -m[1][0]/det;
+	res[1][1] = m[0][0]/det;
+}
+
+
+void matrix_mult(double a[2][2], double b[2][2], double res[2][2])
+{
+	assert(res != a);
+	assert(res != b);
+	res[0][0] = a[0][0]*b[0][0]+a[0][1]*b[1][0];
+	res[0][1] = a[0][0]*b[0][1]+a[0][1]*b[1][1];
+	res[1][0] = a[1][0]*b[0][0]+a[1][1]*b[1][0];
+	res[1][1] = a[1][0]*b[0][1]+a[1][1]*b[1][1];
+}
+
+
+void matrix_multv(const double v[2], double m[2][2], double res[2])
+{
+	double tmp;
+
+	tmp = v[0]*m[0][0]+v[1]*m[0][1];
+	res[1] = v[0]*m[1][0]+v[1]*m[1][1];
+	res[0] = tmp;
+}
+
+
+void matrix_copy(double from[2][2], double to[2][2])
+{
+	to[0][0] = from[0][0];
+	to[0][1] = from[0][1];
+	to[1][0] = from[1][0];
+	to[1][1] = from[1][1];
+}