* adding streamline code and tutorial

* adding python bindings for streamline and python tutorial Former-commit-id: 9abb24e0bc
2016-08-11 10:37:34 -04:00
parent a0664b0a3d
commit e9db1095fd
14 changed files with 742 additions and 0 deletions
@@ -0,0 +1,126 @@
+import sys, os
+import numpy as np
+
+# Add the igl library to the modules search path
+sys.path.insert(0, os.getcwd() + "/../")
+import pyigl as igl
+from shared import TUTORIAL_SHARED_PATH, check_dependencies
+
+dependencies = ["viewer"]
+check_dependencies(dependencies)
+
+# Input mesh
+V = igl.eigen.MatrixXd()
+F = igl.eigen.MatrixXi()
+
+data = igl.StreamlineData()
+state = igl.StreamlineState()
+
+treat_as_symmetric = True
+
+# animation params
+anim_t = 0
+anim_t_dir = 1
+
+
+def representative_to_nrosy(V, F, R, N, Y):
+    B1 = igl.eigen.MatrixXd()
+    B2 = igl.eigen.MatrixXd()
+    B3 = igl.eigen.MatrixXd()
+
+    igl.local_basis(V, F, B1, B2, B3)
+
+    Y.resize(F.rows(), 3 * N)
+    for i in range(0, F.rows()):
+        x = R.row(i) * B1.row(i).transpose()
+        y = R.row(i) * B2.row(i).transpose()
+        angle = np.arctan2(y, x)
+
+        for j in range(0, N):
+            anglej = angle + np.pi * float(j) / float(N)
+            xj = float(np.cos(anglej))
+            yj = float(np.sin(anglej))
+            Y.setBlock(i, j * 3, 1, 3, xj * B1.row(i) + yj * B2.row(i))
+
+
+def pre_draw(viewer):
+    if not viewer.core.is_animating:
+        return False
+
+    global anim_t
+    global start_point
+    global end_point
+
+    igl.streamlines_next(V, F, data, state)
+
+    value = (anim_t % 100) / 100.0
+
+    if value > 0.5:
+        value = 1 - value
+    value /= 0.5
+    r, g, b = igl.parula(value)
+    viewer.data.add_edges(state.start_point, state.end_point, igl.eigen.MatrixXd([[r, g, b]]))
+
+    anim_t += anim_t_dir
+
+    return False
+
+
+def key_down(viewer, key, modifier):
+    if key == ord(' '):
+        viewer.core.is_animating = not viewer.core.is_animating
+        return True
+
+    return False
+
+
+def main():
+    # Load a mesh in OFF format
+    igl.readOFF(TUTORIAL_SHARED_PATH + "bumpy.off", V, F)
+
+    # Create a Vector Field
+    temp_field = igl.eigen.MatrixXd()
+    b = igl.eigen.MatrixXi([[0]])
+    bc = igl.eigen.MatrixXd([[1, 1, 1]])
+    S = igl.eigen.MatrixXd()  # unused
+
+    degree = 3
+    igl.comiso.nrosy(V, F, b, bc, igl.eigen.MatrixXi(), igl.eigen.MatrixXd(), igl.eigen.MatrixXd(), 1, 0.5, temp_field, S)
+    temp_field2 = igl.eigen.MatrixXd()
+    representative_to_nrosy(V, F, temp_field, degree, temp_field2)
+
+    # Initialize tracer
+    igl.streamlines_init(V, F, temp_field2, treat_as_symmetric, data, state)
+
+    # Setup viewer
+    viewer = igl.viewer.Viewer()
+    viewer.data.set_mesh(V, F)
+    viewer.callback_pre_draw = pre_draw
+    viewer.callback_key_down = key_down
+
+    viewer.core.show_lines = False
+
+    viewer.core.is_animating = False
+    viewer.core.animation_max_fps = 30.0
+
+    # Paint mesh grayish
+    C = igl.eigen.MatrixXd()
+    C.setConstant(viewer.data.V.rows(), 3, .9)
+    viewer.data.set_colors(C)
+
+    # Draw vector field on sample points
+    state0 = state.copy()
+
+    igl.streamlines_next(V, F, data, state0)
+    v = state0.end_point - state0.start_point
+    v = v.rowwiseNormalized()
+
+    viewer.data.add_edges(state0.start_point,
+                          state0.start_point + 0.059 * v,
+                          igl.eigen.MatrixXd([[1.0, 1.0, 1.0]]))
+
+    print("Press [space] to toggle animation")
+    viewer.launch()
+
+if __name__ == "__main__":
+    main()