bugGNU Octave - Bugs: bug #46538, FaceAlpha in patch is not working

 
 

bug #46538: FaceAlpha in patch is not working

Submitter:  None
Submitted:  Thu 26 Nov 2015 09:13:25 AM UTC
   
 
Category:  Plotting Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Duplicate Assigned to:  None
Originator Name:  Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * 4.0.0
Operating System:  * Microsoft Windows Fixed Release:  None
Planned Release:  None
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Thu 26 Nov 2015 04:02:04 PM UTC, comment #1: 

This is a known issue with OpenGL in Octave.  See bug #39535.  Marking as a duplicate and closing report.

For a temporary workaround you can try using the gnuplot toolkit.

Rik <rik5>
Group administrator
Thu 26 Nov 2015 09:13:25 AM UTC, original submission:  

Hi,
the attribute FaceAlpha is not working correctly.
Any other value than 1 leads to no color at all.

Here is a small example:

T =[
   1   2   4
   2   3   5
   4   5   7
   5   6   8
   5   4   2
   6   5   3
   8   7   5
   9   8   6];

P = [
   0.00000   0.00000   0.00000   0.50000   0.50000   0.50000   1.00000   1.00000   1.00000
   0.00000   0.50000   1.00000   0.00000   0.50000   1.00000   0.00000   0.50000   1.00000];
  
x = P(1,:); y = P(2,:);
z = 1 - (x-0.5).^2 - (y-0.5).^2;
i=1:length(T);

a1 = [  x(T(i,1)) ; y(T(i,1)) ; z(T(i,1)) ];
a2 = [  x(T(i,2)) ; y(T(i,2)) ; z(T(i,2)) ];
a3 = [  x(T(i,3)) ; y(T(i,3)) ; z(T(i,3)) ];

s  = ( a1(1:2,i) + a2(1:2,i) + a3(1:2,i) )./3;

r1 = a3(:,i) - a1(:,i);
r2 = a2(:,i) - a1(:,i);
n = cross(r1,r2);

dx = n(1,:)./n(3,:);
%dy = n(2,:)./n(3,:);

patch('Faces',T,'Vertices',P','FaceVertexCData',dx','FaceColor','flat','FaceAlpha',1);

Kind regards

Anonymous

 

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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2015-11-26 rik5 StatusNone Duplicate
        Open/ClosedOpen Closed
    2015-11-26 rik5 Dependencies- Depends on bugs #39535

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