Changes between Version 3 and Version 4 of VisitMatlab

Timestamp:

01/18/18 17:41:14 (7 years ago)

Author:

Jonathan

Comment:

—

VisitMatlab

@@ -5 +5 @@
 * FaceVertexCData - Fx1 scalar field defined on the faces
 
+== Example ==
+
+The following matlab script will prompt for a file, import the data, and plot the surface in matlab using the default colormap
+{{{
+[filename,pathname]=uigetfile('*.vtk','Please select a file','*.vtk')
+data=read2DScalarVTK([pathname,filename])
+patch(data,'LineStyle','None','FaceColor','flat')
+}}}
+
+== Line integral convolution ==
+You can also use velocity data to do line integral convolution
+
+
+{{{
+% Fix these to point to the LIC toolbox and update the pathname to your rho.vtk, vx.vtk, and vz.vtk files
+addpath('T:\Documents and Settings\jcarroll\My Documents\MATLAB\LIC\toolbox_image\')
+addpath('T:\Documents and Settings\jcarroll\My Documents\MATLAB\LIC\toolbox_image\toolbox\')
+pathname='Y:\visualizations\iigu\2\data\';
+
+%% Read in rho.vtk, vx.vtk, and vz.vtk (since my slice was in the y direction)
+N=512; %resolution of lic image
+
+filename='rho.vtk';
+data=read2DScalarVTK([pathname,filename])
+[xx,yy]=generatemesh(data,N); %We are going to use the same mesh for all regridding all of the data
+rho=regridmesh(data,xx,yy);
+
+filename='vx.vtk';
+data=read2DScalarVTK([pathname,filename]);
+vx=regridmesh(data,xx,yy);
+
+filename='vz.vtk';
+data=read2DScalarVTK([pathname,filename]);
+vz=regridmesh(data,xx,yy);
+
+%% Normalize velocities since this is expected by LIC routine
+maxnorm=sqrt(max(max(vx.^2+vz.^2)));
+vx=vx/maxnorm;
+vz=vz/maxnorm;
+
+%% Set the options and perform the line integral convolution
+options.histogram = 'linear';
+options.verb = 0;
+options.dt = .5; % time stepping for LIC
+options.flow_correction = 1;
+options.niter_lic = 10; % several iterations gives better results
+options.M0=randn(N); %mask for noise
+z=zeros(N,N,2);
+z(:,:,1)=vz;
+z(:,:,2)=vx;
+result=perform_lic(z,10,options);
+imageplot(result)
+
+%% Now we can use the noise mask generated from LIC on the velocity data, to adjust the brightness of a false color image of the density
+f=.8; %Brightening factor - so that you can still see color through black/white noise
+rho_min=min(min(rho)) %get lower bound
+rho_max=max(max(rho)) %get upper bound
+cmap=colormap('hsv');
+cmap=cmap(1:200,:); %restrict colormap to first 200 entries instead of 256 to avoid circling back around to red
+cdata=interp1(linspace(log(rho_min),log(rho_max),size(cmap,1)), double(cmap), log(rho(:))); %get cdata from scalar field using log scaling
+cdata=reshape(cdata,[N,N,3]).*repmat((1-f)+f*result,[1,1,3]); %multiply by mask
+image(cdata) %draw image
+}}}