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authorWerner Almesberger <werner@almesberger.net>2016-08-17 21:31:56 -0300
committerWerner Almesberger <werner@almesberger.net>2016-08-17 21:31:56 -0300
commitaa48221d9d5cb91ea4bb2eafbf0189e459996a5a (patch)
treeb7b21746ae4f4e4d2bba77138b54670cbd931894 /gfx/misc.c
parent65ba1f11f0ca4bc191df128a28af5c12a330c110 (diff)
downloadeeshow-aa48221d9d5cb91ea4bb2eafbf0189e459996a5a.tar.gz
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eeshow/misc.c: goes to gfx/, too
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+/*
+ * gfx/misc.c - Helper functions for geometry and attributes
+ *
+ * Written 2016 by Werner Almesberger
+ * Copyright 2016 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 <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include "diag.h"
+#include "gfx/misc.h"
+
+
+static bool eq(const int m[6], int xx, int xy, int yx, int yy)
+{
+ return m[1] == xx && m[2] == xy && m[4] == yx && m[5] == yy;
+}
+
+
+unsigned matrix_to_angle(const int m[6])
+{
+ if (eq(m, 1, 0, 0, -1))
+ return 0;
+ if (eq(m, 0, -1, -1, 0))
+ return 90;
+ if (eq(m, -1, 0, 0, 1))
+ return 180;
+ if (eq(m, 0, 1, 1, 0))
+ return 270;
+
+ if (eq(m, -1, 0, 0, -1))
+ return 0;
+ if (eq(m, 0, 1, -1, 0)) /* x-flipped, 90 deg */
+ return 90;
+ if (eq(m, 1, 0, 0, 1)) /* x-flipped */
+ return 180;
+ if (eq(m, 0, -1, 1, 0)) /* x-flipped, 270 deg */
+ return 270;
+
+ fatal("unrecognized matrix %d %d %d %d\n", m[1], m[2], m[4], m[5]);
+}
+
+
+bool matrix_is_mirrored(const int m[6])
+{
+ if (eq(m, 1, 0, 0, -1))
+ return 0;
+ if (eq(m, 0, -1, -1, 0))
+ return 0;
+ if (eq(m, -1, 0, 0, 1))
+ return 0;
+ if (eq(m, 0, 1, 1, 0))
+ return 0;
+
+ if (eq(m, -1, 0, 0, -1))
+ return 1;
+ if (eq(m, 0, 1, -1, 0))
+ return 1;
+ if (eq(m, 1, 0, 0, 1))
+ return 1;
+ if (eq(m, 0, -1, 1, 0))
+ return 1;
+
+ assert(0);
+}
+
+
+int angle_add(int a, int b)
+{
+ a += b;
+ while (a < 0)
+ a += 360;
+ return a % 360;
+}
+
+
+
+int rx(int x, int y, int rot)
+{
+ switch (rot) {
+ case 0:
+ return x;
+ case 90:
+ return y;
+ case 180:
+ return -x;
+ case 270:
+ return -y;
+ default:
+ assert(0);
+
+ }
+}
+
+
+int ry(int x, int y, int rot)
+{
+ switch (rot) {
+ case 0:
+ return y;
+ case 90:
+ return -x;
+ case 180:
+ return -y;
+ case 270:
+ return x;
+ default:
+ assert(0);
+
+ }
+}