Hi Patrick,
I used the following code for updating the shader colors:
self.p1.shader()['colorMap'] = np.array([.01/zmax, # red 1
0, # red 2
0.01, # red 3
0.01/zmax, # green 1
0, # green 2
.05, # green 3
1/zmax, # blue 1
-zmin, # blue 2
1]) # blue 3
Thank you for your help. The library is great and it is very fast.
However, I still do not know how to add x and y axes? In VisPy, there is an
example for plotting
<https://github.com/vispy/vispy/blob/master/examples/basics/scene/surface_plot.py>the
axes, but I could not find a similar one in PyQtGraph. Do you have an
example of this?
Best regards,
Mostafa
On Saturday, April 27, 2019 at 2:47:44 AM UTC-4, Patrick wrote:
>
> Hi,
>
> Yeah, the GL stuff doesn't use the same colour maps as the 2D images. I
> can't see any documentation on the shaders (
> http://www.pyqtgraph.org/documentation/3dgraphics/glmeshitem.html) that
> are used to colour the surface. Looking at the code under shaders.py does
> help though. For the "heightColor" shader, the 9 numbers in the array that
> are used (as in the Surface Plot example) are variables used in a formula
> to compute the RGB colour.
>
> From comment in code:
> ## colors fragments by z-value.
> ## This is useful for coloring surface plots by height.
> ## This shader uses a uniform called "colorMap" to determine how to map
> the colors:
> ## red = pow(z * colorMap[0] + colorMap[1], colorMap[2])
> ## green = pow(z * colorMap[3] + colorMap[4], colorMap[5])
> ## blue = pow(z * colorMap[6] + colorMap[7], colorMap[8])
> ## (set the values like this: shader['uniformMap'] = array([...])
>
> I assume the output RGB values are expressed as a range from 0 to 1. So to
> tweak the example to work with ranges from say zmin to zmax, I think
> something like:
>
> p4.shader()['colorMap'] = np.array([0.2*(zmax - zmin), 2 - zmin, 0.5, 0.2
> *(zmax - zmin), 1 - zmin, 1, 0.2*(zmax - zmin), 0 - zmin, 2])
>
>
> Patrick
>
> On Saturday, 27 April 2019 00:55:42 UTC+9:30, Mostafa wrote:
>>
>> Hi Partick,
>>
>> It works well when we set the following parameters for the
>> GLSurfacePlotItem:
>>
>> computeNormals=False, smooth=False
>>
>>
>> However, I have a problem with the colorMap since the default mapping
>> seems to be for data which is in [-1,1]. I have to change the mapping for
>> an arbitrary data range since in general, I do not know the range but I can
>> retrieve it when the code runs. I looked to the documentation for the
>> colorMap
>> <http://www.pyqtgraph.org/documentation/widgets/imageview.html?highlight=colormap#pyqtgraph.ImageView.setColorMap>
>>
>> but I barely understood how to define it and set in GLSurfacePlotItem.
>> Besides, I want to add x,y axes which are fixed and they are necessary for
>> getting meaning to the surface plot. Any recommendations will be
>> appreciated.
>>
>> Best,
>> Mostafa
>>
>>
>> On Tuesday, April 23, 2019 at 11:44:41 PM UTC-4, Patrick wrote:
>>>
>>> Hi,
>>>
>>> I don't use the 3D capabilities of pyqtgraph, but the example under 3D
>>> Graphics/Surface Plot (
>>> https://github.com/pyqtgraph/pyqtgraph/blob/develop/examples/GLSurfacePlot.py)
>>>
>>> has an animated 3D surface that looks to be rendering at 100+ FPS on my
>>> machine. Does that help? Otherwise if you can post a minimum working
>>> example then we might be able to suggest some ideas.
>>>
>>> Patrick
>>>
>>> On Tuesday, 23 April 2019 13:27:59 UTC+9:30, Mostafa wrote:
>>>>
>>>> Hello,
>>>>
>>>> My eventual goal is to have a surface like the one that Matlab has for
>>>> plotting a 2D array of size N by M. For my application, M and N are not
>>>> greater than 256, so the greatest matrix I have has less than 100K
>>>> entries.
>>>> However, I could not find a remedy for the slow updating of the
>>>> GLSurfacePlotItem. Basically, as the human eye perception is limited, the
>>>> frame update speed should be around 25-30 frame per second. Besides, the
>>>> surface plot is much far away from the nice representation in Matlab where
>>>> the plot has x and y axes with an option to add a colorbar to show the
>>>> color code values. There should be tricks to speed up the process similar
>>>> to the suggestion for 2D plot to disable autoscale in order to update the
>>>> graph much faster.
>>>>
>>>> Any idea?
>>>>
>>>> Best regards,
>>>> Mostafa
>>>>
>>>>
>>>
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