matplotlib · dmcdougall · Mar 15, 2012 · Mar 15, 2012 · Mar 17, 2012 · Mar 22, 2012
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,5 +1,5 @@
-2012-01-08 Add axes.streamplot to plot streamlines of a velocity field.
-		   Adapted from Tom Flannaghan streamplot implementation. -TSY
+2012-02-28 Added plot_trisurf to the mplot3d toolkit. This supports plotting
+           three dimensional surfaces on an irregular grid. - Damon McDougall
 
 2011-12-29 ps and pdf markers are now stroked only if the line width
            is nonzero for consistency with agg, fixes issue #621. - JKS

diff --git a/examples/mplot3d/trisurf3d_demo.py b/examples/mplot3d/trisurf3d_demo.py
@@ -0,0 +1,32 @@
+from mpl_toolkits.mplot3d import Axes3D
+from matplotlib import cm
+import matplotlib.pyplot as plt
+import numpy as np
+
+n_angles = 36
+n_radii = 8
+
+# An array of radii
+# Does not include radius r=0, this is to eliminate duplicate points
+radii = np.linspace(0.125, 1.0, n_radii)
+
+# An array of angles
+angles = np.linspace(0, 2*np.pi, n_angles, endpoint=False)
+
+# Repeat all angles for each radius
+angles = np.repeat(angles[...,np.newaxis], n_radii, axis=1)
+
+# Convert polar (radii, angles) coords to cartesian (x, y) coords
+# (0, 0) is added here. There are no duplicate points in the (x, y) plane
+x = np.append(0, (radii*np.cos(angles)).flatten())
+y = np.append(0, (radii*np.sin(angles)).flatten())
+
+# Pringle surface
+z = np.sin(-x*y)
+
+fig = plt.figure()
+ax = fig.gca(projection='3d')
+
+ax.plot_trisurf(x, y, z, cmap=cm.jet, linewidth=0.2)
+
+plt.show()
diff --git a/lib/mpl_toolkits/mplot3d/axes3d.py b/lib/mpl_toolkits/mplot3d/axes3d.py
@@ -19,6 +19,7 @@
 import matplotlib.collections as mcoll
 from matplotlib import docstring
 import matplotlib.scale as mscale
+from matplotlib.tri.triangulation import Triangulation
 import numpy as np
 from matplotlib.colors import Normalize, colorConverter, LightSource
 
@@ -1570,6 +1571,94 @@ def plot_wireframe(self, X, Y, Z, *args, **kwargs):
 
         return linec
 
+    def plot_trisurf(self, X, Y, Z, *args, **kwargs):
+        '''
+        ============= ================================================
+        Argument      Description
+        ============= ================================================
+        *X*, *Y*, *Z* Data values as 1D arrays
+        *color*       Color of the surface patches
+        *cmap*        A colormap for the surface patches.
+        *norm*        An instance of Normalize to map values to colors
+        *vmin*        Minimum value to map
+        *vmax*        Maximum value to map
+        *shade*       Whether to shade the facecolors
+        ============= ================================================
+
+        Other arguments are passed on to
+        :class:`~mpl_toolkits.mplot3d.art3d.Poly3DCollection`
+        '''
+
+        had_data = self.has_data()
+
+        # TODO: Support custom face colours
+        color = np.array(colorConverter.to_rgba(kwargs.pop('color', 'b')))
+
+        cmap = kwargs.get('cmap', None)
+        norm = kwargs.pop('norm', None)
+        vmin = kwargs.pop('vmin', None)
+        vmax = kwargs.pop('vmax', None)
+        linewidth = kwargs.get('linewidth', None)
+        shade = kwargs.pop('shade', cmap is None)
+        lightsource = kwargs.pop('lightsource', None)
+
+        # TODO: Support masked triangulations
+        tri = Triangulation(X, Y)
+        x = tri.x
+        y = tri.y
+        triangles = tri.triangles
+
+        xt = x[triangles][...,np.newaxis]
+        yt = y[triangles][...,np.newaxis]
+        zt = np.array(Z)[triangles][...,np.newaxis]
+
+        verts = np.concatenate((xt, yt, zt), axis=2)
+
+        # Only need these vectors to shade if there is no cmap
+        if cmap is None and shade:
+            totpts = len(verts)
+            v1 = np.empty((totpts, 3))
+            v2 = np.empty((totpts, 3))
+            # This indexes the vertex points
+            which_pt = 0
+
+        colset = []
+        for i in xrange(len(verts)):
+            avgzsum = verts[i,0,2] + verts[i,1,2] + verts[i,2,2]
+            colset.append(avgzsum / 3.0)
+
+            # Only need vectors to shade if no cmap
+            if cmap is None and shade:
+                v1[which_pt] = np.array(verts[i,0]) - np.array(verts[i,1])
+                v2[which_pt] = np.array(verts[i,1]) - np.array(verts[i,2])
+                which_pt += 1
+
+        if cmap is None and shade:
+            normals = np.cross(v1, v2)
+        else:
+            normals = []
+
+        polyc = art3d.Poly3DCollection(verts, *args, **kwargs)
+
+        if cmap:
+            colset = np.array(colset)
+            polyc.set_array(colset)
+            if vmin is not None or vmax is not None:
+                polyc.set_clim(vmin, vmax)
+            if norm is not None:
+                polyc.set_norm(norm)
+        else:
+            if shade:
+                colset = self._shade_colors(color, normals)
+            else:
+                colset = color
+            polyc.set_facecolors(colset)
+
+        self.add_collection(polyc)
+        self.auto_scale_xyz(X, Y, Z, had_data)
+
+        return polyc
+
     def _3d_extend_contour(self, cset, stride=5):
         '''
         Extend a contour in 3D by creating