linear spline

pgfw/Interpolator.py

@@ -9,6 +9,7 @@ class Interpolator(dict, GameChild):
     def read(self):
         for name, value in self.get_configuration("interpolate").iteritems():
             self[name] = Nodes(value)
+            self[name].print_checkpoints()
 
 
 class Nodes(list):
@@ -36,7 +37,11 @@ class Nodes(list):
             self.set_cubic_splines()
 
     def set_linear_splines(self):
-        pass
+        self.splines = splines = []
+        for ii in xrange(len(self) - 1):
+            x1, y1, x2, y2 = self[ii] + self[ii + 1]
+            m = float(y2 - y1) / (x2 - x1)
+            splines.append(LinearSpline(x1, y1, m))
 
     def set_cubic_splines(self):
         n = len(self) - 1
@@ -65,8 +70,8 @@ class Nodes(list):
             b[jj] = (a[jj + 1] - a[jj]) / h[jj] - \
                     (h[jj] * (c[jj + 1] + 2 * c[jj])) / 3
             d[jj] = (c[jj + 1] - c[jj]) / (3 * h[jj])
-        self.splines = [Spline(a[ii], b[ii], c[ii], d[ii], self[ii].x) for \
-                        ii in xrange(n)]
+        self.splines = [CubicSpline(self[ii].x, a[ii], b[ii], c[ii],
+                                    d[ii]) for ii in xrange(n)]
 
     def get_y(self, t):
         splines = self.splines
@@ -79,6 +84,7 @@ class Nodes(list):
         return "<%i, %s>" % (self.interpolation_method, list(self))
 
     def print_checkpoints(self):
+        print self
         start, end = int(self[0].x), int(self[-1].x)
         step = (end - start) / 8
         for t in xrange(start, end + step, step):
@@ -100,20 +106,31 @@ class Node(list):
 
 class Spline:
 
-    def __init__(self, a, b, c, d, x):
+    def __init__(self, x):
+        self.x = x
+
+
+class CubicSpline(Spline):
+
+    def __init__(self, x, a, b, c, d):
+        Spline.__init__(self, x)
         self.a = a
         self.b = b
         self.c = c
         self.d = d
-        self.x = x
-
-    def __repr__(self):
-        x = self.x
-        return ("<%.1e + %.1e * (x - %.1e) + %.1e * (x - %.1e) ** 2 + " + \
-                "%.1e * (x - %.1e) ** 3>") % (self.a, self.b, x, self.c, x,
-                                            self.d, x)
 
     def get_y(self, t):
         x = self.x
         return self.a + self.b * (t - x) + self.c * (t - x) ** 2 + self.d * \
                (t - x) ** 3
+
+
+class LinearSpline(Spline):
+
+    def __init__(self, x, y, m):
+        Spline.__init__(self, x)
+        self.y = y
+        self.m = m
+
+    def get_y(self, t):
+        return self.m * (t - self.x) + self.y