initial public release.HEADfront

1 files changed, 58 insertions, 0 deletions

diff --git a/triangle.c b/triangle.c
new file mode 100644
index 0000000..5301956
--- /dev/null
+++ b/triangle.c
@@ -0,0 +1,58 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include "dat.h"
+#include "fns.h"
+
+Triangle
+Trian(int x0, int y0, int x1, int y1, int x2, int y2)
+{
+	return (Triangle){Pt(x0, y0), Pt(x1, y1), Pt(x2, y2)};
+}
+
+Triangle
+Trianpt(Point p0, Point p1, Point p2)
+{
+	return (Triangle){p0, p1, p2};
+};
+
+Point
+centroid(Triangle t)
+{
+	return divpt(addpt(t.p0, addpt(t.p1, t.p2)), 3);
+}
+
+void
+triangle(Image *dst, Triangle t, int thick, Image *src, Point sp)
+{
+	Point pl[4];
+
+	pl[0] = t.p0;
+	pl[1] = t.p1;
+	pl[2] = t.p2;
+	pl[3] = pl[0];
+
+	poly(dst, pl, nelem(pl), 0, 0, thick, src, sp);
+}
+
+void
+filltriangle(Image *dst, Triangle t, Image *src, Point sp)
+{
+	Point pl[4];
+
+	pl[0] = t.p0;
+	pl[1] = t.p1;
+	pl[2] = t.p2;
+	pl[3] = pl[0];
+
+	fillpoly(dst, pl, nelem(pl), 0, src, sp);
+}
+
+Triangle
+rotatriangle(Triangle t, double θ, Point c)
+{
+	t.p0 = rotatept(t.p0, θ, c);
+	t.p1 = rotatept(t.p1, θ, c);
+	t.p2 = rotatept(t.p2, θ, c);
+	return t;
+}