[Yt-svn] yt: Adding a ProjectionTransferFunction, to do very simple off-a...

[hg at spacepope.org]

hg Repository: yt
details:   yt/rev/4825a94c4d27
changeset: 1564:4825a94c4d27
user:      Matthew Turk <matthewturk at gmail.com>
date:
Thu Apr 15 10:41:32 2010 -0400
description:
Adding a ProjectionTransferFunction, to do very simple off-axis projections.
Right now the field needs to be linear, not log, but you can do:

linear = vr.ProjectionTransferFunction()
pf.field_info["Density"].take_log = False
vp = pf.h.volume_rendering(L, W, c, (512,512), linear)
vp.ray_cast()

and it gives you a nice looking off-axis projection image.  This is better than
the disk stacker!

diffstat:

 yt/_amr_utils/VolumeIntegrator.pyx                 |   9 +++++++--
 yt/extensions/volume_rendering/TransferFunction.py |  16 ++++++++++++++++
 yt/extensions/volume_rendering/__init__.py         |   3 ++-
 3 files changed, 25 insertions(+), 3 deletions(-)

diffs (87 lines):

diff -r c900b2dfdc66 -r 4825a94c4d27 yt/_amr_utils/VolumeIntegrator.pyx
--- a/yt/_amr_utils/VolumeIntegrator.pyx	Fri Apr 09 11:05:00 2010 -0700
+++ b/yt/_amr_utils/VolumeIntegrator.pyx	Thu Apr 15 10:41:32 2010 -0400
@@ -84,10 +84,12 @@
     int weight_field_id
     int weight_table_id
     int nbins
+    int pass_through
 
 cdef void FIT_initialize_table(FieldInterpolationTable *fit, int nbins,
               np.float64_t *values, np.float64_t bounds1, np.float64_t bounds2,
-              int field_id, int weight_field_id = -1, int weight_table_id = -1):
+              int field_id, int weight_field_id = -1, int weight_table_id = -1,
+              int pass_through = 0):
     fit.bounds[0] = bounds1; fit.bounds[1] = bounds2
     fit.nbins = nbins
     fit.dbin = (fit.bounds[1] - fit.bounds[0])/fit.nbins
@@ -97,11 +99,13 @@
     fit.field_id = field_id
     fit.weight_field_id = weight_field_id
     fit.weight_table_id = weight_table_id
+    fit.pass_through = pass_through
 
 cdef np.float64_t FIT_get_value(FieldInterpolationTable *fit,
                             np.float64_t *dvs):
     cdef np.float64_t bv, dy, dd, tf
     cdef int bin_id
+    if fit.pass_through == 1: return dvs[fit.field_id]
     bin_id = <int> ((dvs[fit.field_id] - fit.bounds[0]) * fit.idbin)
     dd = dvs[fit.field_id] - (fit.bounds[0] + bin_id * fit.dbin) # x - x0
     if bin_id > fit.nbins - 2 or bin_id < 0: return 0.0
@@ -157,7 +161,8 @@
                       tf_obj.tables[i].x_bounds[0],
                       tf_obj.tables[i].x_bounds[1],
                       tf_obj.field_ids[i], tf_obj.weight_field_ids[i],
-                      tf_obj.weight_table_ids[i])
+                      tf_obj.weight_table_ids[i],
+                      tf_obj.tables[i].pass_through)
             self.my_field_tables.append((tf_obj.tables[i],
                                          tf_obj.tables[i].y))
             self.field_tables[i].field_id = tf_obj.field_ids[i]
diff -r c900b2dfdc66 -r 4825a94c4d27 yt/extensions/volume_rendering/TransferFunction.py
--- a/yt/extensions/volume_rendering/TransferFunction.py	Fri Apr 09 11:05:00 2010 -0700
+++ b/yt/extensions/volume_rendering/TransferFunction.py	Thu Apr 15 10:41:32 2010 -0400
@@ -30,6 +30,7 @@
 
 class TransferFunction(object):
     def __init__(self, x_bounds, nbins=256):
+        self.pass_through = 0
         self.nbins = nbins
         self.x_bounds = x_bounds
         self.x = na.linspace(x_bounds[0], x_bounds[1], nbins).astype('float64')
@@ -177,6 +178,21 @@
         for v, a in zip(na.mgrid[mi:ma:N*1j], alpha):
             self.sample_colormap(v, w, a, colormap=colormap)
 
+class ProjectionTransferFunction(MultiVariateTransferFunction):
+    def __init__(self, x_bounds = (-1e30, 1e30)):
+        MultiVariateTransferFunction.__init__(self)
+        self.x_bounds = x_bounds
+        self.nbins = 2
+        self.linear_mapping = TransferFunction(x_bounds, 2)
+        self.linear_mapping.pass_through = 1
+        self.add_field_table(self.linear_mapping, 0)
+        self.alpha = TransferFunction(x_bounds, 2)
+        self.alpha.y *= 0.0
+        self.alpha.y += 1.0
+        self.add_field_table(self.alpha, 0)
+        self.link_channels(0, [0,1,2]) # same emission for all rgb
+        self.link_channels(2, [3,4,5]) # this will remove absorption
+
 class PlanckTransferFunction(MultiVariateTransferFunction):
     def __init__(self, T_bounds, rho_bounds, nbins=256,
                  red='R', green='V', blue='B',
diff -r c900b2dfdc66 -r 4825a94c4d27 yt/extensions/volume_rendering/__init__.py
--- a/yt/extensions/volume_rendering/__init__.py	Fri Apr 09 11:05:00 2010 -0700
+++ b/yt/extensions/volume_rendering/__init__.py	Thu Apr 15 10:41:32 2010 -0400
@@ -27,7 +27,8 @@
 
 from TransferFunction import TransferFunction, ColorTransferFunction, \
                              PlanckTransferFunction, \
-                             MultiVariateTransferFunction
+                             MultiVariateTransferFunction, \
+                             ProjectionTransferFunction
 from yt.amr_utils import PartitionedGrid, VectorPlane, \
                              TransferFunctionProxy
 from grid_partitioner import HomogenizedBrickCollection, \