bezier: initial eval for order 2-4

Makefile.am

@@ -12,6 +12,8 @@ SUBDIRS = test
 
 UTIL_FILES   =		\
     backtrace.hpp   	\
+    bezier.cpp		\
+    bezier.hpp		\
     bitwise.cpp		\
     bitwise.hpp		\
     colour.cpp		\

bezier.cpp

@@ -0,0 +1,124 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim 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 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "bezier.hpp"
+
+#include "debug.hpp"
+
+#include <algorithm>
+#include <iterator>
+
+
+//-----------------------------------------------------------------------------
+template <size_t S>
+util::bezier<S>::bezier (const util::point2f _points[S])
+{
+    std::copy (_points, _points + S, m_points);
+}
+
+
+//-----------------------------------------------------------------------------
+namespace util {
+    template <>
+    point2f
+    bezier<2>::eval (float t)
+    {
+        CHECK_GE (t, 0);
+        CHECK_LE (t, 1);
+
+        auto v0 =      t  * m_points[0];
+        auto v1 = (1 - t) * m_points[1];
+
+        return {
+            v0.x + v1.x,
+            v0.y + v0.y
+        };
+    }
+}
+
+
+//-----------------------------------------------------------------------------
+namespace util {
+    template <>
+    point2f
+    bezier<3>::eval (float t)
+    {
+        CHECK_GE (t, 0);
+        CHECK_LE (t, 1);
+
+        auto v0 =    pow2 (1 - t) * m_points[0];
+        auto v1 = 2 * (1 - t) * t * m_points[1];
+        auto v2 =        pow2 (t) * m_points[2];
+
+        return {
+            v0.x + v1.x + v2.x,
+            v0.y + v1.y + v2.y
+        };
+    }
+}
+
+
+//-----------------------------------------------------------------------------
+namespace util {
+    template <>
+    point2f
+    bezier<4>::eval (float t)
+    {
+        CHECK_GE (t, 0);
+        CHECK_LE (t, 1);
+
+        auto v0 = pow (1 - t, 3) * m_points[0];
+        auto v1 = 3 * pow2 (1 - t) * t * m_points[1];
+        auto v2 = 3 * pow2 (1 - t) * t * m_points[2];
+        auto v3 = pow (t, 3) * m_points[3];
+
+        return {
+            v0.x + v1.x + v2.x + v3.x,
+            v0.y + v1.y + v2.y + v3.y
+        };
+    }
+}
+
+
+//-----------------------------------------------------------------------------
+template <size_t S>
+util::point2f&
+util::bezier<S>::operator[] (size_t idx)
+{
+    CHECK_LT (idx, S);
+
+    return m_points[idx];
+}
+
+
+//-----------------------------------------------------------------------------
+template <size_t S>
+const util::point2f&
+util::bezier<S>::operator[] (size_t idx) const
+{
+    CHECK_LT (idx, S);
+
+    return m_points[idx];
+}
+
+
+//-----------------------------------------------------------------------------
+template class util::bezier<2>;
+template class util::bezier<3>;
+template class util::bezier<4>;

bezier.hpp

@@ -0,0 +1,41 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim 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 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_BEZIER_HPP
+#define __UTIL_BEZIER_HPP
+
+#include "point.hpp"
+
+namespace util {
+    template <size_t S>
+    class bezier {
+        bezier (const util::point2f[S]);
+
+        point2f eval (float t);
+        float distance (point2f);
+
+        point2f& operator[] (size_t idx);
+        const point2f& operator[] (size_t idx) const;
+
+    private:
+        point2f m_points[S];
+    };
+}
+
+#endif